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The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 28 October-4 November. Discrete eruption events were recorded at 0045, 0712, 1448, and 1658 on 29 October. Eruptions on 29 October produced ash plumes that reached 1-1.6 km above the crater rim. One explosive event, captured by infrasound monitoring equipment at 1606 on 2 November, produced white emissions that reached 300 m above the crater rim and drifted SE. A continuous eruption from 1230 until about 2204 on 4 November produced ash emissions to at least 1.2 km above the crater rim; the plume drifted SE. Tremor accompanied the eruption events and ashfall was reported by the Suwanosejima Branch of the Toshima Village Office (3.5 km SSW). The Alert Level remained at 2 (the second level on a five-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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Frequent eruption plumes, explosions, and incandescent ejecta during January-June 2023
Suwanosejima is located in the northern Ryukyu Islands, Japan, and is an 8-km-long island that consists of a stratovolcano and two active summit craters. Volcanism during the 20th century is characterized by Strombolian explosions, ash plumes, and ashfall. The current eruption began in October 2004 and has more recently consisted of intermittent explosions, eruption plumes, ashfall, and incandescent ejecta (BGVN 48:01). Similar activity continued during this reporting period of January through June 2023, based on monthly report from the Japan Meteorological Agency (JMA) and satellite data.
The MIROVA (Middle InfraRed Observation of Volcanic Activity) Log Radiative Power graph of the MODIS thermal anomaly data showed low thermal activity throughout the reporting period (figure 76). Three anomalies were detected during February, four during March, three during April, one during late May, and two during early June. A single thermal hotspot was detected by the MODVOLC thermal alerts system on the NE flank on 7 February. There were only two clear weather days in infrared satellite imagery that showed a thermal anomaly on 7 March and 5 June (figure 77).
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Figure 76. Low thermal activity was detected at Suwanosejima during January through June 2023, based on this MIROVA graph (Log Radiative Power). Three anomalies were detected during February, four during March, three during April, one during late May, and two during early June. Courtesy of MIROVA. |
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Figure 77. Infrared (bands B12, B11, B4) satellite imagery showing two thermal anomalies at the Otake crater of Suwanosejima on 7 March 2023 (left) and 5 June 2023 (right). Courtesy of Copernicus Browser. |
Activity in the Otake crater during January 2023 was relatively low, which prompted JMA to lower the Volcano Alert Level (VAL) from 3 to 2 (on a 5-level scale) on 24 January. The number of explosions recorded during the month was 13. There were 50 volcanic earthquakes detected on the W side of the island, which was roughly comparable to December (44), although near the Otake crater, there were 188 earthquakes recorded, which excluded earthquakes associated with explosions. An aerial overflight conducted on 11 January by the Japan Maritime Self-Defense Force Air Group (JMSDF) reported a gray-white plume rising from the Otake crater. During 26-30 January there was a brief increase in the number of explosions. An eruption at 0331 on 26 January generated an eruption plume that rose 1.7 km above the crater rim and ejected large blocks 400 m S from the crater. Nighttime crater incandescence was visible in a highly sensitive surveillance camera starting on 26 January. According to the Toshima Village Office, Suwanosejima Branch Office, ashfall was occasionally observed in the village (3.5 km SSW). According to observations conducted by the University of Tokyo Graduate School of Science, Kyoto University Disaster Prevention Research Institute, Toshima Village, and JMA, the amount of sulfur dioxide emissions released during the month was 200-600 tons per day (t/d).
Eruptive activity in the Otake crater continued during February; the total number of explosions increased during this month from 13 to 56. There were 119 volcanic earthquakes detected on the W side of the island and 449 near the Otake crater, excluding earthquakes associated with explosions. During 15-21 February there was a brief increase in the number of explosions, and large blocks were ejected as far as 1 km from the crater. An explosion at 2131 on 15 March ejected material 900 m SE (figure 78). Eruptions on 18 and 27 February generated plumes that rose 2 km above the crater (figure 79). By 21 February the number of explosions reached 42, though no large-scale volcanic earthquakes were reported. Nighttime crater incandescence continued from late January through February. Ashfall was also occasionally observed in Toshima Village. The amount of sulfur dioxide emissions released during the month was 700 t/d.
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Figure 78. Webcam image of the explosion at Suwanosejima’s Otake crater at 2131 on 15 February 2023. Crater incandescence was visible, and large blocks were ejected 900 m from the crater (white dashed line). Courtesy of JMA (Volcanic activity commentary for Suwanosejima, February 2023). |
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Figure 79. Webcam image of the explosion at Suwanosejima’s Otake crater at 1606 on 18 February 2023. The eruption plume rose 2 km above the crater rim. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, February 2023). |
The number of explosions at the Otake crater increased during 2-5 March; 28 explosions were detected during this time. Large volcanic blocks were ejected 500 m from the crater. As a result, the VAL was increased to 3 on 5 March. There were 65 explosions recorded throughout the month. On the W side of the island, 63 volcanic earthquakes were reported, and closer to the Otake crater, 422 were detected, excluding earthquakes associated with explosions. Nighttime crater incandescence continued, as well as occasional ashfall in Toshima Village. On 16 March an eruption produced a volcanic plume that rose 2.4 km above the crater rim (figure 80). The amount of sulfur dioxide emissions released during the month was 200-1,100 t/d.
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Figure 80. Webcam image of an eruption plume rising 2.4 km above the Otake crater at Suwanosejima at 0644 on 16 March 2023. Photo has been color corrected. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, March 2023). |
Eruptive activity continued at the Otake crater during April. Eruption plumes rose as high as 2 km above the crater rim and large blocks were ejected as far as 500 m from the crater. The number of explosions decreased to one throughout the month, although nighttime crater incandescence remained visible in the surveillance camera. Rumbling and ashfall continued intermittently in Toshima Village. There were 32 volcanic earthquakes detected, and 129 volcanic earthquakes near the Otake crater, not including those associated with explosions. According to JMA, the amount of sulfur dioxide released during the month was 200-1,400 t/d. On 16 April at 0402 an eruption ejected incandescent material 500 m S from the crater.
Activity continued at the Otake crater in May. An eruption plume rose 1.8 km above the crater rim and large volcanic blocks were ejected 300 m from the crater. The number of explosions remained low throughout the month (7) and nighttime crater incandescence persisted. Occasional ashfall was reported in Toshima Village. As many as 44 volcanic earthquakes were recorded on the W side of the island, and 205 were recorded closer to the Otake crater, which was higher compared to the previous month. Generally, the amount of sulfur dioxide released during the month ranged 400-700 t/d, but on 19 May the amount increased to 2,600 t/d. On 16 May an eruption produced a volcanic plume that rose 1.8 km above the crater rim.
Eruptive activity was relatively low in June; the number of explosions generally decreased and on 9 June the VAL was lowered to 2. Nighttime crater incandescence continued, and according to the Toshima Village Office, rumbling and ashfall were also noted occasionally. There were 31 explosions throughout the month and 28 volcanic earthquakes detected on the W side of the island and as many as 722 volcanic earthquakes were recorded near the Otake crater. During 13-19 June, JMA reported a brief increase in the number of explosions. On 15 June at 2200 an eruption generated a volcanic plume that rose 2 km above the crater rim. An eruption on 16 June at 2147 ejected material 400 m SE from the crater. The amount of sulfur dioxide emitted was relatively low, at 100 t/d on 27 June.
Information Contacts: Japan Meteorological Agency (JMA), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Copernicus Browser, Copernicus Data Space Ecosystem, European Space Agency (URL: https://dataspace.copernicus.eu/browser/).
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The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 28 October-4 November. Discrete eruption events were recorded at 0045, 0712, 1448, and 1658 on 29 October. Eruptions on 29 October produced ash plumes that reached 1-1.6 km above the crater rim. One explosive event, captured by infrasound monitoring equipment at 1606 on 2 November, produced white emissions that reached 300 m above the crater rim and drifted SE. A continuous eruption from 1230 until about 2204 on 4 November produced ash emissions to at least 1.2 km above the crater rim; the plume drifted SE. Tremor accompanied the eruption events and ashfall was reported by the Suwanosejima Branch of the Toshima Village Office (3.5 km SSW). The Alert Level remained at 2 (the second level on a five-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 21-28 October. Crater incandescence was observed nightly in webcam images. A period of continuous ash emissions during 1706-2320 on 22 October produced ash plumes that rose as high as 1.5 km above the crater rim and drifted NE and E, rising into the weather clouds. Eruptive events at 0103 on 23 October, at 0515, 0554, 0747, 0804, 1633, and 1714 on 27 October, and at 0215 on 28 October generated ash plumes that rose 1-1.6 km above the crater rim and drifted mainly E and W. An explosion was recorded at 0247 on 25 October; details of emissions were not reported. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 14-22 October. An eruptive event at 0410 on 16 October produced an ash-and-gas plume that rose 1 km above the crater rim and drifted SW. An ash-and-gas plume at 0743 on 18 October and at 1706 on 22 October rose as high as 1.5 km above the crater rim and drifted NW and NE, respectively. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 7-14 October. Crater incandescence was observed nightly in webcam images. Eruptive events at 0221 and 0750 on 7 October produced ash-and-gas plumes that rose 1.1-1.5 km above the crater rim; the plume from the second event drifted E. Ash-and-gas plumes were continuously emitted during 0943-1310, rose as high as 1.6 km above the crater rim, and drifted E. Ash-and-gas plumes from eruptive events at 0333 and 1540 on 10 October rose 1.3 km above the crater rim and drifted S and SE, respectively. Three eruptive events on 11 October, at 0403, 0737, and 1130, produced ash-and-gas plumes that rose 1-1.3 km straight up above the crater rim or drifted SE. An ash-and-gas plume from an eruptive event at 1352 on 13 October rose 1 km above the crater rim and drifted W. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 30 September-7 October. Crater incandescence was observed nightly in webcam images. Three eruptive events on 30 September produced ash-and-gas plumes that rose 1-1.3 km above the crater rim and drifted W. At 0031 on 1 October continuous ash-and-gas plumes rose 0.6-1.1 km above the crater rim and drifted W, N, and NE; ash was no longer detected by 1710. An eruptive event on 4 October generated an ash-and-gas plume that rose 1.5 km above the crater rim. Continuous ash-and-gas emissions that began at 1256 on 4 October likely ceased around 0620 on 5 October, although weather conditions obscured views; ash-and-gas plumes rose as high as 2 km above the crater rim and drifted NE, N, and NW. On 7 October ash-and-gas plumes rose 1.1-1.5 km above the crater rim and drifted E. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 23-30 September. Crater incandescence was observed nightly in webcam images. Explosions were recorded by the seismic network at 0337, 0428, 0730, and 1720 on 25 September, at 1415 and 1554 on 26 September, and at 1810 on 28 September. The explosions generated ash-and-gas plumes that rose 1-1.6 km above the crater rim and drifted mainly W and SW. Eruptive events during 24-28 and 30 September produced ash-and-gas plumes that rose 1-1.6 km above the crater rim and drifted and drifted mainly W and SW. Occasional ashfall was reported at the Suwanosejima Branch Office in Toshima village (3.5 km SSW), though dates were unspecified. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 16-23 September. At 1403 on 17 September an eruptive event generated an ash plume that rose 1.3 km above the crater rim and drifted W. An explosion was recorded at 0233 on 20 September, though no details were reported about possible emissions. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 9-16 September and crater incandescence was observed nightly in webcam images. Explosions were recorded at 1728 on 9 September, at 1001 on 11 September, at 1345 on 12 September, and at 1948 on 13 September. Volcanic plumes generated by the explosions rose as high as 800 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 2-9 September and crater incandescence was observed nightly in webcam images. The seismic network recorded 12 explosions and numerous eruptive events. Occasional rumbling and ashfall were reported at the Suwanosejima Branch Office in Toshima village (3.5 km SSW) on unspecified dates. The explosions were recorded at 2027 on 2 September, at 1103 and 2304 on 4 September, at 0425, 1602, and 1736 on 5 September, at 0541, 1938, and 2036 on 6 September, at 2121 on 7 September, at 2144 on 8 September, and at 1728 on 9 September. The explosions generated ash plumes that rose 0.4-1.7 km above the crater rim and drifted NW, W, and SW; details about the last two explosions were unknown. Large blocks were sometimes ejected as far as 600 m from the vent. As many as 11 daily eruptive events were also recorded and produced ash plumes that rose as high as 1.6 km above the crater rim and drifted NW, W, and SW. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 26 August-2 September. Crater incandescence was observed nightly in webcam images. An explosion at 0056 on 1 September generated an ash plume that rose 1 km above the crater rim and drifted SE. Eruptive events at 0813 and 0917 on 1 September and at 0338 and 0416 on 2 September generated ash plumes that rose 1-1.1 km above the crater rim and drifted SE and N. Rumbling was heard at the Suwanosejima Branch Office in Toshima village (3.5 km SSW) on an unspecified date. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 19-26 August. Crater incandescence was observed nightly in webcam images. An explosion at 0900 on 22 August generated an ash plume that rose 1.5 km straight up above the crater rim. An eruptive event at 0448 on 25 August generated an ash plume that rose 2.3 km above the carter rim and drifted S. An ash plume from an explosion at 1623 on 26 August rose 1.3 km above the crater rim and drifted SW. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 12-19 August. Crater incandescence was observed nightly in webcam images. Explosions at 0054 and 0207 on 12 August generated ash plumes that rose 400-600 m above the crater rim and drifted SE. Eruptive events were recorded at 2345 on 12 August, at 0432 on 13 August, at 1559, 1825, 1844, 2018, 2040, 2043, 2337, and 2356 on 15 August, at 0124, 0719, 1351, 1718, 1808, 2037, and 2336 on 16 August, and at 0147 on 17 August. Ash plumes from the events rose 1-1.6 km above the crater rim, sometimes drifting NE, N, NW, and W. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 5-12 August. Crater incandescence was observed nightly in webcam images. Eruptive events were recorded at 2109 on 6 August, at 0056, 0124, 0236, 0313, 0349, 0657, and 0955 on 7 August, and at 0207, 1156, 1225, and 1440 on 8 August. Ash plumes rose 1-1.4 km above the crater rim and drifted mainly SW, S, and SE. Explosions were recorded at 1457, 1625, and 1717 on 10 August, though emissions were not visually observed. Explosions at 2103 on 10 August, at 1011 and 1213 on 11 August, and at 0054 and 0207 on 12 August generated ash plumes that rose 200-600 m above the crater rim and drifted SE; sometimes the plumes rose into weather clouds. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 29 July-5 August. Crater incandescence was observed nightly in webcam images. Eruption events at 1907 and 2339 on 2 August produced ash plumes that rose 1 km above the crater rim and drifted toward the SE, as well as ejected large ballistic projectiles as far as 400 m from the center of the crater. Rumbling was reported by the Suwanosejima Branch of the Toshima Village Office (3.5 km SSW). Tremor was registered at the same time as the eruption events. The Alert Level remained at 2 (the second level on a five-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 22-29 July. Crater incandescence was observed nightly in webcam images. An explosion at 1527 on 24 July produced an ash plume that rose 700 m above the crater rim and drifted W. Another explosion was detected at 1231 on 25 July, though details about possible emissions were unknown. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 15-22 July and produced volcanic plumes that rose as high as 1.2 km above the crater rim and drifted N and NW. Large blocks were ejected as far as 300 m from the vent, though no explosions were recorded. Crater incandescence was observed nightly in webcam images. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 1-8 July and produced volcanic plumes that rose as high as 500 m above the crater rim. Crater incandescence was observed nightly in webcam images. No explosions were recorded. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 24 June-1 July and produced volcanic plumes that rose as high as 500 m above the crater rim. Crater incandescence was observed nightly in webcam images. No explosions were recorded. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 17-24 June and produced volcanic plumes that rose as high as 500 m above the crater rim. Crater incandescence was observed nightly in webcam images. No explosions were recorded. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 10-17 June and produced volcanic plumes that rose as high as 800 m above the crater rim. Crater incandescence was observed nightly in webcam images. No explosions were recorded. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 3-10 June and produced volcanic plumes that rose as high as 700 m above the crater rim. Crater incandescence was observed nightly in webcam images. No explosions were recorded. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 27 May-3 June and produced volcanic plumes that rose as high as 500 m above the crater rim. Crater incandescence was observed nightly in webcam images. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 20-27 May. Crater incandescence was observed nightly in webcam images. An explosion at 0019 on 22 May generated an ash plume that rose 900 m above the crater rim and drifted W. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 13-20 May. Crater incandescence was observed nightly in webcam images. Emissions rose as high as 800 m above the crater rim and blocks were ejected as far as 200 m from the crater’s center; no explosions were detected. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 6-13 May. Crater incandescence was observed nightly in webcam images. An explosion was recorded at 2145 on 8 May though details of plumes were unknown. An explosion at 0831 on 9 May produced an ash plume that rose 400 m above the crater rim and drifted S. Eruptive events at 2339 on 9 May and at 0213 on 10 May generated ash plumes that rose 1.1-1.3 km above the crater rim and drifted SW. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 29 April-6 May. Crater incandescence was observed nightly in webcam images. Emissions rose as high as 600 m above the crater rim and blocks were ejected as far as 300 m from the crater’s center; no explosions were detected. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 22-29 April. Crater incandescence was observed in webcam images nightly. Emissions rose as high as 800 m above the crater rim; no explosions were detected. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 15-22 April. Crater incandescence was observed in webcam images nightly. No explosions were detected but ashfall was reported in Toshima village (3.5 km SSW); dates were not specified. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 25 March-1 April. Crater incandescence was observed in webcam images nightly. No explosions were detected but eruption plumes rose as high as 500 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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Japan Meteorological Agency (JMA) reported that the eruption at Suwanosejima's Ontake Crater continued during 20-26 March. Crater incandescence was observed nightly in infrared camera images. A total of seven explosions were registered by the seismic network; resulting ash plumes rose up to 1.3 km above the crater rim before drifting N and SE and ejected large ballistic projectiles (20-30 cm in diameter) as far as 600 m away from the center of the crater. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 11-18 March. Crater incandescence was observed in webcam images nightly and large blocks were sometimes ejected up to 600 m from the vent. An explosion at 0501 on 18 March generated an ash plume that rose 900 m above the crater rim and drifted SE. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 4-11 March. Crater incandescence was observed in webcam images nightly and large blocks were sometimes ejected up to 400 m from the vent. An eruptive event at 0905 on 4 March generated an ash plume that rose straight up as high as 1.3 km above the crater rim. Explosions recorded at 1256 on 6 March, 1002 on 7 March, 1746 on 8 March, and 2333 on 9 March generated ash plumes that rose as high as 900 m before sometimes merging into weather clouds; plumes drifted S and SE. An explosion was recorded at 0138 on 7 March, though emission details were unknown. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 26 February-4 March. Crater incandescence was observed in webcam images nightly and large blocks were sometimes ejected up to 600 m from the vent. Explosions recorded at 0431, 1402, 1910, and 1918 on 26 February, and at 0135, 0249, and 0617 on 27 February produced ash plumes that rose 500-800 m above the crater rim and drifted S. An eruptive event at 0104 on 28 February produced an ash plume that rose 1.4 km above the crater rim and drifted S. Explosions at 1537 on 28 February and 0013 on 2 March generated ash plumes that rose 500-600 m and drifted W and SE, respectively. An explosion was recorded at 0255 on 1 March but emission details were unknown. Ash plumes from eruptive events at 1530 on 3 March and 0905 on 4 March produced ash plumes that rose 800-1,300 m above the crater rim; the 3 March plume rose into weather clouds. Ashfall was reported in Toshima village (3.5 km SSW), though dates were not specified. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 19-26 February. Crater incandescence was observed in webcam images nightly. Large blocks were sometimes ejected up to 400 m from the vent. Explosions were recorded at 0616 on 19 February, at 0604 and 2157 on 24 February, and at 1149 on 25 February; details of emissions were unknown. Eruptive events at 1702 and 2056 on 23 February produced ash plumes that rose at least 1 km above the crater rim and drifted S. Explosions at 2343 on 25 February and at 0431, 1402, 1910, and 1918 on 26 February produced ash plumes that rose 400-800 m above the crater rim and drifted S. The plume from the explosion at 1918 on 26 February rose to 800 m before entering into weather clouds. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 12-19 February. Crater incandescence was observed in webcam images nightly. Eruptive events at 0810 and 1414 on 13 February generated ash plumes that rose 1.1-1.3 km above the crater rim and drifted N. An explosion at 1908 on 15 February generated an ash plume that rose 400 m and drifted E. Explosions were also detected at 2125 on 15 February and at 0616 on 19 February, though details of emissions were unknown. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 5-12 February. Crater incandescence was observed in thermal webcam images. A total of two eruptions were reported; large volcanic blocks were ejected as far as 500 m away from the vent. The eruptions recorded at 1147 on 6 February and 1314 on 12 February produced ash plumes that rose 1 km above the crater rim before drifting SE and S, respectively. Seismicity consisted of a few volcanic earthquakes detected in the W area of the island, and episodes of tremor that occurred at the same time as the eruptive events. The Alert Level remained at 2 (on a 5-level scale), and the public was warned to stay at least 1 km away from Ontake crater in all directions.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 29 January-5 February. Crater incandescence was observed in webcam images nightly and rumbling was occasionally heard in Toshima village (3.5 km SSW). A total of three explosions were recorded during the week, ejecting large blocks as far as 300 m from the vent. The first explosion, at 1135 on 29 January, produced an ash plume that rose 1 km above the crater rim and drifted SE. The second explosion was recorded at 0950 on 31 January, though details about emissions were unknown. The third explosion, at 2223 on 31 January, generated an ash plume that rose 500 m and drifted E. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 22-29 January. A total of 15 explosions were recorded during the week, with 1-4 occurring each day. Ash plumes rose as high as 1 km above the crater rim and drifted SE and E, and large blocks were ejected as far as 400 m from the vent. Crater incandescence was observed in webcam images nightly and rumbling was occasionally heard in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 16-22 January and crater incandescence was observed nightly. The Alert Level was lowered to 2 at 1100 on 19 January because the probability of material being ejected more than 1 km laterally had decreased. There were seven explosions detected from 1759 on 19 January to 1222 on 22 January. Details about the plumes were reported for two of them and unknown for the remaining ones; on 21 January an explosion at 1632 produced an ash plume that rose 1 km above the crater rim and drifted SE and an explosion at 2215 produced an ash plume that rose 600 m above the crater rim before merging into weather clouds. The public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 8-15 January. Eruptive events on 11 January produced ash plumes that rose as high as 1.1 km above the crater rim and drifted SE. An explosion at 0548 on 13 January produced an ash plume that rose 800 m and drifted SE. At 0022 on 14 January an explosion ejected large blocks 1.1 km to the N and 1 km to the S of the vent and produced an ash plume that rose 500 m above the crater rim. The Alert Level was raised to 3 (on a 5-level scale) and the public was warned to stay 2 km away from the crater. Another eruptive event at 2313 on 15 January generated an ash plume that rose more than 1 km above the crater rim and drifted S.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 1-8 January. No explosions were detected, though large blocks were ejected as far as 400 m from the vent. Ash plumes rose 1-2 km above the crater rim during 1-2, 6, and 8 January and drifted in multiple directions. Ash emissions were continuous during 0157-0620 and 0834-2235 on 2 January. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 25 December 2023-1 January 2024. No explosions were detected, though large blocks were ejected as far as 300 m from the vent. Eruption plumes rose 1-1.6 km above the crater rim during 27-28 December, 30 December, and 1 January, and drifted SW, S, SE, and E. Ashfall was reported in Toshima village (3.5 km SSW), though dates were not specified. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 18-25 December. No explosions were detected, though large blocks were ejected as far as 200 m from the vent. Eruption plumes rose as high as 1,200 m above the crater rim during 24-25 December and drifted S and SE. Ashfall was reported in Toshima village (3.5 km SSW), though dates were not specified. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 11-18 December and crater incandescence was visible nightly. No explosions were detected, though eruption plumes rose as high as 800 m above the crater rim and large blocks were ejected as far as 200 m from the vent. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 4-11 December and crater incandescence was visible nightly. No explosions were detected, though ash plumes rose as high as 900 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued at Suwanosejima’s Ontake Crater during 27 November-4 December. Crater incandescence was observed nightly in webcam images. Eruption plumes rose as high as 900 m above the vent. Seismicity consisted of volcanic tremors associated with eruptions, and a few volcanic earthquakes detected in the W area of Suwanosejima. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater in all directions.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 20-27 November and crater incandescence was visible nightly. No explosions were detected, though ash plumes rose as high as 1.2 km above the crater rim and drifted mainly SE and W during 20-21 and 25 November. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 13-20 November and crater incandescence was visible nightly. No explosions were detected, though ash plumes rose at least 1 km above the crater rim and drifted mainly SE on 14, 16, and 20 November. Ashfall was reported in Toshima village (3.5 km SSW); dates were not specified. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 6-13 November. An eruptive event at 1423 on 11 November produced a column of ash that rose as high as 1.2 km above the crater rim. Ashfall was reported 3.5 km SW of Mitake crater. Incandescence was observed around Ontake crater during most nights. Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 30 October-6 November. Eruptive events during 30-31 October and 2 and 4 November generated ash plumes that rose as high as 1.5 km above the crater rim and drifted NW, S, and W; on 30 October and 4 November the ash plumes rose into weather clouds and may have gone higher than observed. The eruptive events ejected large blocks as far as 300 m from the vent. Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 23-30 October. Eruptive events during 25-27 and 29-30 October generated plumes that rose as high as 1.9 km above the crater rim and drifted SE, S, and SW and ejected large blocks as far as 400 m from the vent. Ash fell in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 16-23 October and crater incandescence was visible nightly. Eruptive events generated plumes that rose as high as 1.6 km above the crater rim and drifted S and SE and ejected large blocks as far as 400 m from the vent. Ash fell in Toshima village (3.5 km SSW). Explosions recorded at 0454 and 0517 on 16 October produced ash plumes that rose 500-600 m above the crater rim and drifted SE. During an overflight on 17 October scientists observed no notable changes in the crater and surrounding areas. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 9-16 October and crater incandescence was visible nightly. During 11-12 and 16 October eruptive events generated plumes that rose as high as 1.5 km above the crater rim and drifted W, SW, and SE, and ejected large blocks as far as 400 m from the vent. A total of eight explosions were recorded by the seismic network at 1522 on 14 October, at 0337, 0433, 0555, 1008, and 1539 on 15 October, and at 0454 and 0517 on 16 October. Ash plumes from the explosions rose as high as 900 m and drifted SE. Ash fell in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 2-9 October. Crater incandescence was visible nightly, and blocks were ejected as far as 600 m from the crater. Explosions at 0304, 2141, and 2359 on 2 October, at 0112 on 3 October, and 1326 on 6 October produced ash plumes that rose as high as 1 km above the crater rim and drifted SW and W. An explosion was recorded at 0428 on 3 October, though emission details were unknown. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 25 September-2 October. Eruptive events on 25, 27, and 30 September, and 1-2 October, produced ash plumes that rose as high as 1.3 km above the crater rim and ejected blocks as far as 300 m from the crater. Crater incandescence was visible nightly. Ash emissions were continuous from 0510 to 0555 on 1 October. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 18-25 September. Eruptive events produced plumes that rose as high as 1.9 km above the crater rim and ejected blocks as far as 300 m from the crater. Crater incandescence was visible nightly. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 11-18 September. Eruptive events at 0511 and 1228 on 15 September produced ash plumes that rose 1-1.8 km above the crater rim and drifted N and NW, respectively. Blocks were ejected as far as 300 m from the crater. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 4-11 September. Eruptive events at 0221, 0301, and 0333 on 9 September produced ash plumes that rose 1.1-1.4 km above the crater rim and drifted W. Ash emissions were continuous during 0404-0740 and rose as high as 2 km above the crater rim. More eruptive events at 1437 on 10 September and at 0319 on 11 September produced ash plumes that rose 1.7-1.8 km. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 28 August-4 September. Eruptive events produced volcanic plumes that rose as high as 700 m above the crater rim. An eruptive event at 1949 on 4 September produced an ash plume that rose 1 km above the crater rim and drifted SW. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 21-28 August. Eruptive events produced volcanic plumes that rose as high as 1.4 km above the crater rim and produced ashfall in Toshima village (3.5 km SSW). Events at 0544, 0742, 0824, 1424, and 1704 on 25 August produced ash plumes that rose 1.1-1.2 km above the crater rim and drifted NE, W, and SW. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 14-21 August. Eruptive events at 0911 on 16 August, 1303 on 20 August, and 0317 on 21 August produced ash plumes that rose 1-1.1 km above the crater rim and drifted SE, SW, and W, respectively. Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 7-14 August. An eruptive event produced a plume that rose 1 km above the crater rim at 1447 on 12 August. No explosions or ejecta were observed during this time period. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 24-31 July. An eruptive event reported on 31 July produced an eruption plume that rose 1.2 km above the crater rim. No explosions or ejecta were observed during this time period. Nighttime crater incandescence was visible in webcam images. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 17-24 July. Multiple eruptive events during 19 and 21-24 July produced ash plumes that rose as high as 1.5 km above the crater rim. Some of the plumes drifted N and NW. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater. The Alert Level remained at 2 (on a 5-level scale) and residents were warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that minor eruptive activity continued at Suwanosejima’s Ontake crater during 28 June-3 July. Eruptions were recorded during 28-29 June and on 2 July. Ash plumes at 0952 and 1638 on 28 June rose up to 1.2 km above the crater and drifted NE. The next day, at 1232 and 2129 on 29 June, ash plumes rose up to 1 km above the crater and drifted NE. Ash plumes rose to 1.5 km and drifted NE at 2025 on 2 July. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued at low levels during 21-27 June. At 1521 on 25 June an eruptive event produced an ash plume that rose 1.3 km above the crater rim and drifted to the N, and ejected a large block 100 m from the crater. At 0036 on 27 June an ash plume rose 1.2 km and drifted N, followed by another at 0909 that rose 1.8 km and drifted E. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 14-19 June. A total of 526 volcanic earthquakes, 26 explosions, and 18 eruptive events were recorded by seismic monitoring stations throughout the week; activity was most notable during 15-16 June with totals of 164 volcanic earthquakes and 10 explosions. Ash plumes were observed daily; the tallest plumes rose 2 km above the crater rim on 15 and 16 June. Continuous emissions during 0936-1355 on 16 June rose as high as 2 km and drifted SE and SW. Some events ejected large volcanic blocks up to 400 m from the crater during 14-18 June. Incandescent ejecta from explosions during the nights of 18-19 June were sometimes visible in webcam images. Occasional ashfall and rumbling noises were reported in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued, though monitoring parameters had been showing a declining trend. Blocks had not been ejected more than 1 km from the crater after 15 February and the number of explosions had decreased since March. GNSS (Global Navigation Satellite Systems) deformation measurements did not indicate accumulating magma beneath the W part of the island and the number volcanic earthquakes in that area was low. Eruptive activity during 7, 9-10, and 12 June generated ash plumes that rose 1-1.5 km above the crater rim and drifted in multiple directions. An explosion at 1803 on 7 June produced an ash plume that rose 1.4 km and drifted E. Explosions were recorded at 0230 on 9 June and 1758 on 10 June, though details of any emissions were unknown. The Alert Level was lowered to 2 (on a 5-level scale) at 1100 on 9 June and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 29 May-5 June. At 1407 on 30 May an explosion generated an ash plume that rose 800 m. Incandescence at the crater was visible at night during 2-5 June. Four eruptive events occurred during 4-5 June. Ash plumes rose to 1.1 km and drifted E and S at 1455 and 2327 on 4 June, respectively. At 1037 and 2349 on 5 June ash plumes rose 1-1.1 km and drifted E. The Alert Level remained at 3 (on a 5-level scale) and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 22-29 May and incandescence at the crater was visible nightly. Daily ash plumes from eruptive events rose as high as 1.6 km above the crater rim and drifted in multiple directions. Blocks were ejected as far as 300 m from the crater. At 2245 on 23 May an explosion generated an ash plume that rose 600 m and drifted S. The Alert Level remained at 3 (on a 5-level scale) and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 15-22 May. Incandescence was visible nightly, and seismicity remained elevated during 15-19 May. On 16 May an ash plume rose 1.8 km above the crater rim and caused ashfall in Toshima village (3.5 km SSW). On 17 May, an ash plume rose to 1.1 km and drifted NW. Four eruptive events were observed during 21-23 May. On 21 May an eruptive event ejected volcanic blocks up to 200 m from the crater and produced an ash plume that rose 1.8 km above the crater and drifted E. On 22 May an ash plume rose to 1 km above the crater and drifted SE. Two eruptive events on 23 May generated ash plumes that rose 600 m above the crater and drifted SE and S. The Alert Level remained at 3 (on a 5-level scale) and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 8-15 May and crater incandescence was reported nightly. Explosions recorded at 0701, 1200, and 2330 on 8 May produced ash plumes that rose as high as 1 km above the crater rim and mainly drifted SE. Explosions were also recorded at 1358 and 1648, though characteristics of associated emissions were unknown. Eruptive events at 2001 on 8 May, 1753 on 9 May, 0405, 0647, and 1236 on 11 May, and 1919 on 13 May generated ash plumes that rose as high as 1.3 km and generally drifted S, SW, and N. The Alert Level remained at 3 (on a 5-level scale) and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 1-8 May, and crater incandescence was reported nightly. No explosions were recorded during 1-5 May, but eruptive activity produced periodic ash plumes that rose as high as 1.6 km above the crater rim and ejected blocks 300 m from the crater. Explosions at 0701, 1200, 2001, and 2330 on 8 May generated ash plumes that rose as high as 1 km and drifted SE and SW. Explosions also occurred at 1358 and 1648, though no associated emissions were reported. The Alert Level remained at 3 (on a 5-level scale) and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 24 April-1 May. No explosions were recorded, but eruptive activity produced periodic ash plumes, and during 28 April-1 May blocks were ejected as far as 200 m from the vent. On 27 April at 0838 and 0943 ash-and-gas plumes rose 1-1.1 km above the crater rim and drifted W, and on 28 April at 0643 an ash-and-gas plume rose 1.5 km and drifted NW. The Alert Level remained at 3 (on a 5-level scale) and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 17-24 April. No explosions were recorded, but eruptive activity produced periodic ash plumes and ejected blocks as far as 300 m from the vent. On 17 April ash plumes rose 1-1.5 km above the crater rim and drifted E and SE, and on 18 April an ash plume rose 2 km and drifted N. Ashfall was reported in Toshima village (3.5 km SSW) during 17-21 April. On 23 April an ash plume rose 1.1 km and drifted SW. The Alert Level remained at 3 (on a 5-level scale) and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 10-17 April. Eruptive activity produced ash plumes during 12-14 and 17 April that rose as high as 1.5 km above the crater rim and drifted NW, S, SE, and E. Large blocks were ejected as far as 500 m from the vent. Crater incandescence was visible nightly. The Alert Level remained at 3 (on a 5-level scale) and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 3-10 April. Eruptive activity produced ash plumes that rose as high as 1.6 km above the crater rim and drifted mainly SE, E, and N. Large blocks were ejected as far as 300 m from the vent. Crater incandescence was visible at night during 3-7 April and one explosion was detected during 7-10 April. The Alert Level remained at 3 (on a 5-level scale) and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 27 March-3 April. Two eruption events on 31 March and 3 April ejected large volcanic blocks 300-400 m from the crater and the accompanying eruption plumes rose 1.7-2 km above the crater rim. Crater incandescence was visible nightly. Ashfall was reported in Toshima village (3.5 km SSW). The Alert Level was raised from 2 to 3 on 5 March and remained at 3 (on a 5-level scale) and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 20-27 March. Eruptive activity including three explosions sent ash plumes as high as 2 km above the rim and ejecting large blocks as far as 300 m from the vent. Crater incandescence was visible nightly. Occasional ashfall was reported in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and residents were warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 13-20 March. A total of 20 explosions were recorded, sending ash plumes as high as 2.4 km above the crater rim and ejecting large blocks as far as 500 m from the vent. Crater incandescence was visible at night. Occasional ashfall was reported in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and residents were warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 6-13 March. A total of 18 explosions were recorded, sending ash plumes as high as 2.3 km above the crater rim and ejecting large blocks as far as 400 m from the vent. Crater incandescence was visible at night. Occasional ashfall was reported in Toshima village (3.5 km SSW). On 8 March grayish-white plumes were seen rising from the vent during an overflight. No other changes were noted compared to the last overflight conducted on 29 September 2022. The Alert Level remained at 2 (on a 5-level scale) and residents were warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the number of explosions at Suwanosejima's Ontake Crater began to increase on 2 February and further increased on 2 March. Activity intensified and a total of 25 explosions were recorded during 1-5 March. Ash plumes rose as high as 1.4 km above the crater rim and large blocks were ejected as far as 500 m from the vent. Crater incandescence was visible at night. Occasional ashfall and rumbling noises were reported in Toshima village (3.5 km SSW). Since large blocks could be ejected further than the restricted zone of 1 km, JMA raised the Alert Level to 3 (on a 5-level scale) at 0640 on 5 March and warned the public to stay 2 km away from the crater. Explosions continued during 5-7 March. Ash plumes rose as high as 2 km above the crater rim and large blocks were ejected as far as 500 m.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 20-27 February. A total of 20 explosions were recorded, sending ash plumes as high as 2 km above the crater rim and ejecting large blocks as far as 400 m from the vent. Crater incandescence was visible at night. Occasional ashfall and rumbling noises were reported in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and residents were warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 13-20 February. Occasional ashfall and rumbling noises were reported in Toshima village (3.5 km SSW). The number of explosions per day increased on 13 February and then gradually decreased beginning on 16 February; a total of about 24 explosions occurred during the week. At 2131 on 15 February an explosion produced an ash plume that rose 1.3 km above the crater rim and ejected large blocks as far as 900 m SE. An explosion around an hour later, at 2237, ejected large blocks as far as 700 m SE. During 18-20 February explosions produced ash plumes that rose as high as 2 km above the crater rim and ejected large blocks as far as 400 m from the vent. Crater incandescence was visible at night. The Alert Level remained at 2 (on a 5-level scale) and residents were warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 6-13 February with a total of 10 explosions recorded by the seismic network. The explosions produced eruption plumes that rose as high as 1.5 km above the crater rim and ejected large blocks as far as 400 m from the vent. Crater incandescence was observed nightly. Occasional ashfall was reported in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and residents were warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 30 January-6 February with a total of seven explosions recorded by the seismic network. The explosions produced eruption plumes that rose as high as 1.5 km above the crater rim and ejected large blocks as far as 400 m from the vent. Crater incandescence was observed nightly. Occasional ashfall and rumbling noises were reported in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and residents were warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 23-30 January. The number of explosions increased on 26 January; a total of 13 explosions were recorded during the week. The explosions produced eruption plumes that rose as high as 1.7 km above the crater rim and entered weather clouds. Large blocks were ejected as far as 400 m from the crater’s center. Nighttime crater incandescence was observed starting on 26 January. Ashfall was reported in Toshima village (3.5 km SSW). The Alert Level remained at 2 (on a 5-level scale) and residents were warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 16-23 January. No explosions were recorded, though eruption plumes rose as high as 1.2 km above the crater rim and blocks were ejected as far as 300 m from the vent. Ashfall was occasionally reported in Toshima village (3.5 km SSW). JMA noted that the number of explosions began decreasing in mid-October 2022 and the last explosion was recorded on 16 November. Additionally, plume heights had occasionally risen higher than 2 km above the crater rim during October-November 2022, but starting in December the heights had generally been at or below 1 km. Other data had also indicated low levels of activity; the probability of material being ejected more than 1 km away from the crater had decreased. The Alert Level was lowered to 2 (on a 5-level scale) on 24 January, and residents were warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 9-16 January. No explosions were recorded, though during 9-13 January eruption plumes rose as high as 1.1 km above the crater rim and blocks were ejected as far as 300 m from the vent. Ashfall was occasionally reported in Toshima village (3.5 km SSW). Eruption plumes rose as high has 700 m during 13-16 January. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 2-9 January. No explosions were recorded, though eruption plumes rose as high as 1.3 km above the crater rim. During 2-6 January blocks were ejected as far as 200 m from the vent and ashfall was occasionally reported in Toshima village (3.5 km SSW). The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 26 December 2022-3 January 2023. No explosions were recorded. Eruption plumes rose as high as 1 km above the crater rim, and blocks were ejected as far as 200 m from the vent. Ashfall was occasionally reported in Toshima village (3.5 km SSW) during 28-30 December. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 19-26 December. No explosions were recorded. Eruption plumes rose at least 1 km above the crater rim and disappeared into weather clouds, and blocks were ejected as far as 30 m from the vent. Ashfall was occasionally reported in Toshima village (3.5 km SSW) during 23-26 December. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 12-19 December. No explosions were recorded. Eruption plumes rose at least 1.7 km above the crater rim and blocks were ejected as far as 100 m from the vent. Crater incandescence was visible at night during 12-16 December and ashfall was occasionally reported in Toshima village (3.5 km SSW) during 16-19 December. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 5-12 December and crater incandescence was visible nightly. No explosions were recorded. Eruption plumes rose as high as 1.7 km above the crater rim and blocks were ejected as far as 200 m from the vent. Ashfall was occasionally reported in Toshima village (3.5 km SSW). The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 28 November-5 December and crater incandescence was visible nightly. No explosions were recorded. Eruption plumes rose as high as 1.8 km above the crater rim and blocks were ejected as far as 300 m from the vent. Ashfall was occasionally reported in Toshima village (3.5 km SSW). The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 21-28 November and crater incandescence was visible nightly. Eruption plumes rose as high as 1.3 km above the crater rim and blocks were ejected as far as 300 m from the vent. Ashfall was occasionally reported in Toshima village (3.5 km SSW). The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 14-21 November and crater incandescence was visible nightly. Eruption plumes generally rose 600 m above the crater rim and blended into weather clouds. An explosion at 0251 on 15 November ejected blocks 500 m from the vent and produced an eruption plume that rose 2.3 km above the crater rim and drifted SE. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 9-15 November and crater incandescence was visible nightly. An explosion at 2238 on 11 November produced an eruption plume that rose 1.6 km above the crater rim. Ash plumes during 15 November rose 1-1.3 km above the crater and drifted SE. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 31 October-7 November and crater incandescence was visible nightly. An explosion at 0137 on 4 November produced an eruption plume that rose 2.4 km above the crater rim and ejected large blocks 200 m from the vent. Ashfall was reported in Toshima village (3.5 km SSW). The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 24-31 October and crater incandescence was visible nightly. A total of six explosions produced eruption plumes that rose as high as 2.1 km above the crater rim and ejected blocks as far as 300 m from the vent. Occasional rumbling noises and ashfall were reported in Toshima village (3.5 km SSW). The number of volcanic earthquakes increased starting at 0600 on 31 October; a total of about 355 events, located beneath the W flank, were recorded by 1500.The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 17-24 October. Crater incandescence was visible nightly. A total of 119 explosions during 17-21 October produced eruption plumes that rose as high as 2 km above the crater rim and ejected blocks as far as 800 m from the vent. Occasional rumbling noises and ashfall were reported in Toshima village (3.5 km SSW). Only one explosion was reported during 21-24 October. Plumes rose as high as 1.5 km and blocks were ejected as far as 200 m from the vent. Ashfall was reported in Toshima village. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 10-17 October. A total of 71 explosions produced eruption plumes that rose as high as 2 km above the crater rim and ejected blocks as far as 600 m from the vent. Crater incandescence was visible nightly. Occasional ashfall was reported in Toshima village (3.5 km SSW) during the first half of the week. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 3-10 October. A total of 55 explosions produced eruption plumes that rose as high as 2.4 km above the crater rim and occasionally merged into weather clouds. The explosions ejected large blocks as far as 700 m from the vent. Crater incandescence was visible nightly. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 30 September-3 October. A total of 38 explosions produced eruption plumes that rose as high as 1.6 km above the crater rim and occasionally ejected large bombs from the vent. Crater incandescence was visible nightly and ash sometimes fell in Toshima village (3.5 km SSW). The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater. [Correction: JMA noted that the number of explosions had been increasing since 26 September; they raised the Alert Level to 3 on 28 September.]
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 19-26 September. A total of 19 explosions produced eruption plumes that rose as high as 2 km above the crater rim. Crater incandescence was visible nightly and ash fell in Toshima village (3.5 km SSW). The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 12-19 September. A total of 11 explosions produced eruption plumes that rose as high as 1.4 km above the crater rim and ejected large blocks 600 m from the vent. Volcanic tremor was occasionally recorded. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 5-12 September. A total of 15 explosions produced eruption plumes that rose as high as 2 km above the crater rim. Large blocks were ejected 700 m from the vent. Crater incandescence was observed nightly, and volcanic tremor was occasionally recorded. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 31 August-5 September. There were four explosions that likely produced eruption plumes, though weather clouds prevented visual confirmation. Large blocks were ejected 700 m from the vent. Crater incandescence was observed nightly, and volcanic tremor was occasionally recorded. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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At 2151 on 28 August a large eruptive event at Suwanosejima's Ontake Crater ejected large bombs 800 m above the vent and produced an eruption plume that rose into overhead weather clouds. Crater incandescence was visible in webcam images overnight. By 0900 on 29 August three more explosions were recorded and produced ash plumes that rose as high as 1.3 km above the vent. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 15-22 August. There were six explosions, producing eruption plumes that rose as high as 900 m above the crater rim and ejecting large blocks 600 m from the vent. Crater incandescence was observed nightly, and volcanic tremor was occasionally recorded. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the number of daily explosions at Suwanosejima's Ontake Crater began increasing on 2 August and remained elevated through 7 August; their frequency began decreasing on 8 August. About 11 explosions were recorded during 8-15 August. Eruption plumes rose as high as 2 km above the crater rim and large ballistics were ejected as far as 800 m from the crater. Incandescence from the crater was often visible at night. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the number of explosions at Suwanosejima's Ontake Crater increased during 2-8 August, when around 30 were recorded; nine of those were detected on 7 August. During 7-8 August eruption plumes rose as high as 2 km above the crater rim and mingled with weather clouds. Large ballistics were ejected 600 m from the crater’s center. Incandescence from the crater was visible at night. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 25 July-2 August. One explosion produced an eruption plume that rose more than 1.8 km above the crater rim and caused ashfall in Toshima village (3.5 km SSW). The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 18-25 July. There were four explosions, producing eruption plumes that rose as high as 1.2 km above the crater rim and ejecting larger material 300 m from the vent. Crater incandescence was observed nightly, and volcanic tremor was occasionally recorded. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 11-18 July. There were 13 explosions, producing eruption plumes that rose as high as 1.5 km above the crater rim and ejecting material 700 m from the vent. Crater incandescence was observed nightly. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA lowered the Alert Level for Suwanosejima to 2 (on a 5-level scale) on 11 July, reflecting declining activity and a reduced likelihood that tephra would be ejected farther than 1 km. The number and intensity of explosions had been variable since early April but decreased overall, and material had not been ejected beyond a 1-km radius. Eruption plume heights had occasionally exceeded 3 km above the crater rim since July 2021 but none that high had been observed since mid-April. The number of volcanic earthquakes had temporality increased on 17 May but were generally low. The public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 27 June-4 July and crater incandescence was visible nightly. Emissions rose as high as 1 km above the crater rim and tephra was ejected 200-600 m from the vent. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 20-27 June. Emissions rose as high as 2 km above the crater rim and material was ejected as far as 200 m from the vent. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 13-20 June. Crater incandescence was visible at night. Emissions rose as high as 1.6 km above the crater rim and material was ejected as far as 300 m from the vent. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 6-13 June. Crater incandescence was visible at night. One explosion was recorded during 6-10 June, producing a plume that rose 2 km above the crater rim and ejecting material 300 m away from the vent. During 10-13 June eruption plumes rose as high as 1.5 km above the crater rim and material was ejected as far as 300 m from the vent. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 27 explosions were recorded at Suwanosejima's Ontake Crater during 30 May-6 June. Eruption plumes rose as high as 1.6 km above the crater rim and material was ejected as far as 600 m from the vent. Crater incandescence was visible at night. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 33 explosions were recorded at Suwanosejima's Ontake Crater during 23-30 May. Eruption plumes rose as high as 1.9 km above the crater rim and material was ejected 500 m above the vent. Crater incandescence was visible at night. Ash fell in Toshima village (3.5 km SSW) during 23-27 May. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 16-23 May. Eruption plumes rose as high as 1.9 km above the crater rim and material was ejected 400 m above the vent. Ash fell in Toshima village (3.5 km SSW) and in other areas within 5 km. Three explosions were recorded during 20-23 May and crater incandescence from the crater was visible at night. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 9-16 May. Eruption plumes rose as high as 1 km above the crater rim and material was ejected 400 m above the vent; no explosions were recorded. Ash fell in Toshima village (3.5 km SSW) during 13-16 May. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 2-9 May. Eruption plumes rose as high as 1.3 km above the crater rim; no explosions were recorded. Crater incandescence was occasionally visible during 2-6 May and ash fell in Toshima village (3.5 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 25 April-2 May. Eruption plumes rose as high as 800 m above the crater rim and crater incandescence was occasionally visible. One explosion, recorded in Toshima village (3.5 km SSW), generated an ash plume that rose 1.3 km and into weather clouds. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 18-25 April. Eruption plumes rose as high as 1.5 km above the crater rim; no explosions were recorded. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 11-18 April. One explosion produced an eruption plume that rose as high as 2.7 km above the crater rim. Ashfall was reported in Toshima village (3.5 km SSW) and in other areas as far as 5 km away. No explosions were recorded during 15-18 April, though emissions rose 1.1 km. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 4-8 April. Two explosions produced eruption plumes that rose as high as 3.3 km above the crater rim and ejected blocks as far as 500 m from the crater. Ashfall was reported in Toshima village (3.5 km SSW). No eruptive activity was noted during 9-11 April, though emissions rose 700 m. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 29 March through 4 April. As many as 122 explosions were recorded, and crater incandescence was visible nightly. Eruption plumes rose as high as 2.8 km above the crater rim and ejected blocks as far as 900 m from the crater. Ashfall was reported in Toshima village (3.5 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 21-28 March. As many as 42 explosions were recorded, and crater incandescence was visible nightly. Eruption plumes rose as high as 2.3 km above the crater rim and ejected blocks as far as 800 m from the crater. Ashfall was reported in Toshima village (3.5 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 14-21 March. As many as 27 explosions were recorded, and crater incandescence was visible nightly. Eruption plumes rose as high as 1.9 km above the crater rim and ejected blocks 300-500 m away from the crater. Ashfall was reported as far as 5 km away, including in Toshima village (3.5 km SSW) during 18-21 March. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 7-14 March. Eruption plumes rose as high as 1.7 km above the crater rim and ejected blocks 400 m away from the crater. Ashfall was reported in Toshima village (3.5 km SSW) during 7-11 March. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruption plumes at Suwanosejima's Ontake Crater rose as high as 2.4 km during 28 February-7 March and blocks were ejected as far as 800 m from the crater. Three explosions were recorded and crater incandescence was visible nightly. Ashfall was reported in areas as far as 5 km from the vent including in Toshima village (3.5 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 13 explosions were recorded at Suwanosejima's Ontake Crater during 21-28 February. The explosions produced ash plumes that rose as high as 2.2 km above the crater rim and ejected blocks 300-400 m away from the crater. Ashfall was reported in Toshima village (3.5 km SSW) and crater incandescence was visible nightly. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 102 explosions were recorded at Suwanosejima's Ontake Crater during 14-21 February. The explosions produced ash plumes that rose as high as 1.8 km above the crater rim. Ashfall was reported in Toshima village (3.5 km SSW) during 14-18 February, and nighttime crater incandescence was visible during 18-21 February. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that five explosions were recorded at Suwanosejima's Ontake Crater during 7-14 February. The explosions produced ash plumes that rose as high as 2 km above the crater rim and ejected large blocks 300-400 m from the crater. Ashfall was reported in Toshima village (3.5 km SSW) during 11-14 February. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that volcanic plumes from Suwanosejima's Ontake Crater rose as high as 2.2 km above the crater rim during 31 January-7 February. Ashfall was reported in Toshima village (3.5 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima's Ontake Crater was visible nightly during 24-28 January. There were 27 explosions recorded, producing ash plumes that rose at least 3 km above the crater rim and ejected material up to 1 km away from the crater. Rumbling sounds and ashfall were reported in Toshima village (3.5 km SSW). Eruptive activity continued during 28-31 January. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima's Ontake Crater was visible nightly during 17-24 January. There were 46 explosions recorded, producing ash plumes that rose at least 1.8 km above the crater rim and ejected material up to 1 km away from the crater. Rumbling sounds and ashfall were reported in Toshima village (3.5 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima's Ontake Crater was visible nightly during 10-17 January. There were 157 explosions recorded, producing ash plumes that rose as high as 2 km above the crater rim and ejected material up to 800 m away from the crater. Eruption sounds were heard in Toshima village (4 km SSW). Volcanologists observed ash-and-steam plumes rising from the crater during an overflight on 17 January. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima's Ontake Crater was visible nightly during 3-10 January and 368 explosions were recorded. The explosions produced ash plumes that rose as high as 2 km above the crater rim and ejected material up to 1.1 km away from the crater. Eruption sounds were heard in Toshima village (4 km SSW) and ash fell there during 7-10 January. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima's Ontake Crater was visible nightly during 27 December 2021 to 3 January 2022. The number of explosions totaled 124. The explosions produced ash plumes that rose as high as 2.2 km above the crater rim and ejected material up to 1.1 km distance from the crater. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima's Ontake Crater was visible nightly during 20-27 December. The number of explosions totaled 143 during 22-24 December. Plumes rose as high as 3.1 km above the crater rim and bombs were ejected 700 m from the crater. Explosive activity increased during 24-27 December with explosions totaling 361. Plumes rose as high as 1.5 km and bombs were ejected 800 m form the vent. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima's Ontake Crater was visible nightly during 13-20 December. The number of explosions increased on 15 December; there were 152 explosions during 13-17 December. Eruption plumes rose as high as 1.2 km above the crater rim and bombs were ejected 800 m from the vent. There were 288 explosions recorded during 17-20 December. Resulting plumes rose as high as 1.9 km above the crater rim and bombs were ejected as far as 800 m from the vent. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima's Ontake Crater was visible nightly during 6-13 December. No explosions were detected by the seismic network, though eruption plumes rose 1-3.4 km and material was ejected 400-700 m away from the crater. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 29 November-6 December about 47 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 1.7 km above the crater rim and ejected blocks 600-700 m away from the crater. Plumes from non-explosive events rose as high has 2.3 km. Crater incandescence was visible nightly and ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 22-29 November about 41 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2.7 km above the crater rim and ejected blocks 500-800 m from the crater. Crater incandescence was visible nightly. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that plumes from Suwanosejima's Ontake Crater rose 180-200 m above the crater rim during 15-22 November. Large blocks were ejected 300 m from the crater and were deposited in a ballistic pattern during 15-19 November, and ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that seven explosions at Suwanosejima's Ontake Crater were recorded during 1-8 November. The explosions produced ash plumes that rose as high as 2 km above the crater rim and ejected material 300-600 m from the carter. Ashfall was reported in Toshima village (4 km SSW) during 1-5 November. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that an explosion at 1317 on 26 October at Suwanosejima's Ontake Crater produced an eruption plume that rose as high as 3.3 km above the crater rim and ejected material 1.9 km away from the crater. Ashfall was reported in Toshima village (4 km SSW). No explosions were recorded during 29 October-1 November, though eruption plumes rose as high as 2.4 km and tephra was ejected 400 m from crater. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 13 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2.7 km above the crater rim during 11-18 October. Large volcanic bombs were ejected 500-700 m from the crater. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 52 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2.4 km above the crater rim during 4-11 October. Large volcanic bombs were ejected as far as 1.1 km from the crater. Crater incandescence was visible nightly. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 129 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 3 km above the crater rim during 27 September-4 October. Large volcanic bombs were ejected as far as1 km from the crater. Crater incandescence was visible nightly. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the number of explosions per day at Suwanosejima's Ontake Crater had increased on 16 September and remained elevated through 27 September. A total of 105 explosions were recorded during 20-27 September. Eruption plumes mainly rose as high as 2.9 km above the crater rim and material was ejected as far as 800 m away from the crater. Ashfall was reported in Toshima village (4 km SSW). Notably, an explosion at 2349 on 20 September ejected material as far as 1.2 km SE. At 0711 on 26 September an eruptive event produced a plume that rose 5.4 km; weather clouds prevented confirmation of ejected bombs, but a large amount of ash fell in Toshima village. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the number of daily explosions at Suwanosejima's Ontake Crater increased on 16 September and remained elevated through 20 September. Eruption plumes rose as high as 2.4 km above the crater rim and material was generally ejected 300 m away from the crater. Notably, explosions at 2014 on 16 September and at 0212 on 17 September ejected material almost 1 km S and SE, respectively. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that four explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 3.3 km above the crater rim during 3-10 September. Large volcanic bombs were ejected 500 m from the crater. Crater incandescence was visible nightly. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that three explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 4.8 km above the crater rim during 27 August-3 September. Large volcanic bombs were ejected 700 m from the crater. Crater incandescence was visible nightly and ashfall was often reported in Toshima village (4 km SSW). The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 15 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 3.2 km above the crater rim during 20-27 August. Large volcanic bombs were ejected 300 m from the crater. Crater incandescence was visible nightly and ashfall was often reported in Toshima village (4 km SSW); a large amount of ash fell in the village on 26 August. At 1231 on 28 August an eruption produced an ash plume that rose 4.8 km above the crater; weather clouds prevented clear views, though observations indicated that the event continued at least through 1700. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that explosions at Suwanosejima's Ontake crater were detected on 19, 20, and 21 August. The first explosion at 0137 on 19 August produced an ash plume that rose 3 km above the crater and drifted NE, followed by another at 1613 that generated an ash plume 2.2 km above the crater and drifted N. A small amount of ashfall was reported in Yakushima, Nishinoomote, and Nakatane. A third explosion at 2059 that day produced an ash plume that rose 2.5 km above the crater and drifted N; ashfall was reported in Toshima village (4 km SSW). Explosions at 0628 and 0713 on 20 August generated ash plumes that rose 2.5-3 km above the crater and drifted N, resulting in ashfall in Toshima village, with smaller amounts of ash in Yakushima, Mishima, Ibusuki, Minamikyushu, and Makurazaki. On 21 August at 0617 an explosion generated an ash plume that rose 3.2 km above the crater and drifted N. A large amount of ashfall (over 1 mm) was reported in Toshima village and smaller amounts (less than 0.1 mm) were reported in Makurazaki, Minamisatsuma, Minamikyushu, Kagoshima, Ibusuki, and Hioki. A second explosion followed at 0906 that produced an ash plume 3.2 km above the crater that drifted N. The Tokyo VAAC reported ash plumes to 1.5-3.9 km (5,000-13,000 ft) altitude that drifted NE during 18-25 August. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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JMA reported that 10 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2.2 km above the crater rim during 6-13 August. Large volcanic bombs were ejected 400 m from the crater. Crater incandescence was visible nightly and ashfall was occasionally reported in Toshima village (4 km SSW). The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 13 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 3.8 km above the crater rim during 30 July-6 August. Large volcanic bombs were ejected 500 m from the crater. Crater incandescence was visible nightly. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 26-30 July bombs ejected from Suwanosejima's Ontake Crater landed as far as 500 m away from the crater and plumes rose as high as 3.3 km above the rim. Explosive activity had been elevated during June and most of July, with ejected bombs landing as far as 1 km from the crater. Activity peaked on 22 July but then declined afterwards. The Alert Level was lowered to 2 (on a 5-level scale) at 1100 on 29 July and JMA warned the public to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported ongoing explosions at Suwanosejima's Ontake Crater during 19-26 July and that crater incandescence was visible on some nights. There were 31 explosions recorded on 22 July after two days of no explosions. An explosion at 1500 on 23 July produced an ash plume that rose 1.6 km and ejected bombs 200 m. Eruption plumes during 23-26 July rose as high as 2.3 km; it was unknown if bombs were ejected from the crater due to weather conditions. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that five explosions at Suwanosejima's Ontake Crater during 12-19 July ejected bombs as far as 400 m from the crater. Crater incandescence was visible on some nights and ashfall was occasionally reported in Toshima village (4 km SSW). An explosion at 2330 on 12 July produced an ash plume that rose 3.6 km. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 96 explosions at Suwanosejima's Ontake Crater produced eruption plumes that generally rose 2-2.4 km above the crater rim during 5-12 July. Large volcanic bombs were ejected mainly 400 m from the crater and crater incandescence was visible nightly. Eruption sounds were sometimes heard in Toshima village (4 km SSW). An explosion at 0439 on 8 July ejected large bombs 800 m NW and an explosion at 1319 on 12 July produced an ash plume that rose 3 km. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 35 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2 km above the crater rim during 28 June-5 July. Large volcanic bombs were ejected 400 m from the crater and crater incandescence was visible nightly. Eruption sounds were heard in Toshima village (4 km SSW). The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima's Ontake Crater increased during 21-23 June with multiple events. Eruptive events at 2254 on 21 June and 0004 on 23 June ejected large incandescent bombs 900 m NW and SE (respectively) from the crater; eruption plumes rose 1.2 km above the crater rim. The increased activity prompted JMA to raise the Alert Level to 3 at 0015 on 23 June and warn the public to stay at least 2 m away from the active crater. During an overflight on 23 June scientists noted incandescence on the crater floor and that there were several high-temperature deposits scattered in and around the crater. White plumes rose 200-300 m above the crater rim. Multiple eruptive events during 23-28 June ejected bombs 600 m and produced ash plumes that rose as high as 2.3 km.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 15 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 1.8 km above the crater rim during 11-18 June. Large volcanic bombs were ejected 500 m from the crater. Ashfall was reported in Toshima village (4 km SSW). Crater incandescence was visible nightly. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 28 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2.4 km above the crater rim during 4-11 June. Large volcanic bombs were ejected 500 m from the crater. Ashfall was reported in Toshima village (4 km SSW). Crater incandescence was visible nightly. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 33 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2.6 km above the crater rim during 28 May-4 June. Large volcanic bombs were ejected 500 m from the crater. Ashfall was reported in Toshima village (4 km SSW). Crater incandescence was visible nightly. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 47 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2.1 km above the crater rim during 21-28 May. Large volcanic bombs were ejected 700 m from the crater. Ashfall was reported in Toshima village (4 km SSW). Crater incandescence was visible nightly. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that intermittent eruptive activity at Suwanosejima's Ontake Crater produced plumes that rose as high as 1.6 km above the crater rim during 14-21 May. Large volcanic bombs were ejected 300 m from the crater. Crater incandescence was visible overnight during 18-19 May. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that six explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2 km above the crater rim during 7-14 May. Large volcanic bombs were ejected 400 m from the crater. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 35 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2.4 km above the crater rim during 30 April-7 May. Large volcanic bombs were ejected 700 m from the crater. Crater incandescence was visible nightly. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that 45 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 1.7 km above the crater rim during 23-30 April. Large volcanic bombs were ejected 400 m from the crater. Nighttime crater incandescence was visible during 24-25 April. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence from Suwanosejima's Ontake Crater was occasionally visible at night during 16-23 April. Five explosions generated ash plumes that rose as high as 1.7 km above the crater rim and ejected bombs 600 m away. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence from Suwanosejima's Ontake Crater was visible at night during 9-16 April. Seven explosions generated ash plumes that rose as high as 1.5 km above the crater rim and ejected bombs 400 m away. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence from Suwanosejima's Ontake Crater was visible at night during 5-9 April. Four explosions generated ash plumes that rose as high as 1.6 km above the crater rim and ejected bombs 600 m away. Ashfall was reported in Toshima village (4 km SSW) during 8-9 April. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 30-31 March large volcanic bombs were ejected at least 41 times from Suwanosejima's Ontake Crater as high as 800 m above the crater rim and to distances as far as 1 km. The Alert Level was raised to 3 (on a 5-level scale) at 0330 on 31 March and the public was warned to stay outside a 2 km radius of the crater. The increased activity prompted an overflight that same day where scientists confirmed several hundred high-temperature bomb deposits with a thermal camera within a 1 km radius. Explosions at 2205 on 30 March and 0257 on 31 March ejected bombs onto the S and SE flanks, respectively. Grayish-white emissions rose from the crater. After 1500 eruption plumes rose as high as 1.4 km above the crater rim. The number of explosions decreased; two per day were recorded during 1-2 April and one was recorded on 3 April. The Alert Level was lowered to 2 on 5 April and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
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JMA reported that the seismic network for Suwanosejima's Ontake Crater detected a total of 17 explosions during 19-26 March. These events produced eruption plumes that rose as high as 1.2 km above the crater rim, drifting S, W, and SW, and ejected bombs as far as 500 m away from the crater. Incandescence from the crater was occasionally visible at night. On 30 March at least 18 explosions were detected, generating ash plumes that rose 600-1,500 m above the crater drifting E, SE, and NE and ejecting material as far as 800 m S of the crater. On 31 March the Alert Level was raised to 3 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that the seismic network for Suwanosejima’s Ontake Crater detected a total of 11 explosions during 12-19 March. These events produced eruption plumes that rose as high as 1.7 km above the crater rim and ejected bombs up to 700 m away from the crater. Incandescence from the crater was occasionally visible at night. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that the seismic network for Suwanosejima’s Ontake Crater detected a total of 29 explosions during 5-12 March, less than the 131 explosions recorded previous week. These events produced eruption plumes that rose as high as 1.5 km above the crater rim. Incandescence from the crater was occasionally visible at night. Rumbling was heard in a village 4 km SSW. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported intermittent eruptive events at Suwanosejima’s Ontake Crater during 26 February-2 March. Bombs were ejected as far as 600 m away from the crater and ashfall was reported in Toshima village (4 km SSW). The number of explosions began increasing on 2 March; the total recorded through 1500 on 7 March was 139, but by 1500 on 8 March there was only one additional explosion. The Tokyo VAAC reported that ash plumes rose 0.9-2.1 km (3,000-7,000 ft) a.s.l. during 3-7 March. An explosion at 0317 on 6 March ejected tephra as high as 500 m above the crater rim and bombs 900 m away. The Alert Level remained at 2 (on a 5-level scale).
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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JMA reported intermittent eruptive events at Suwanosejima’s Ontake Crater during 19-26 February. These events produced ash plumes that rose as high as 1.8 km above the crater rim and ejected bombs 200 m away from the crater. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported intermittent eruptive events at Suwanosejima’s Ontake Crater during 12-19 February. These events produced ash plumes that rose as high as 1.5 km above the crater rim and ejected bombs 300 m away from the crater. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima’s Ontake Crater was occasionally visible at night during 5-12 February. Intermittent eruptive events produced ash plumes that rose as high as 1.2 km above the crater rim and ejected bombs 500 m away from the crater. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima’s Ontake Crater was occasionally visible at night during 29 January-5 February. Intermittent explosions produced ash plumes that rose as high as 1.2 km above the crater rim and ejected bombs 300 m away from the crater. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima’s Ontake Crater was occasionally visible at night during 22-29 January. Intermittent explosions produced ash plumes that rose as high as 1.4 km above the crater rim and ejected bombs 200 m away from the crater. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima’s Ontake Crater was occasionally visible at night during 15-22 January. Intermittent explosions produced ash plumes that rose as high as 2.5 km above the crater rim and ejected bombs 400 m away from the crater. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima’s Ontake Crater was visible nightly during 11-15 January. Intermittent explosions produced ash plumes that rose as high as 1.4 km above the crater rim and ejected bombs 400 m away from the crater. The Alert Level was lowered to 2 (on a 5-level scale) on 14 January; JMA noted that no large bombs were ejected more than 1 km from the crater beginning on 29 December 2020.
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima’s Ontake Crater was visible nightly during 4-11 January. Two explosions on 5 January produced ash plumes that rose 1.2 km above the crater rim and ejected bombs 400 m away from the crater. Two explosions during 9-10 January generated ash plumes that rose 1 km and again ejected bombs 400 m away. The Alert Level remained at 3 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that two explosions, on 29 and 30 December, were recorded at Suwanosejima’s Ontake Crater. Crater incandescence was visible at night during 1-4 January, and eruption plumes rose as high as 1.2 km above the crater rim. The Alert Level remained at 3 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that eruptive activity at Suwanosejima’s Ontake Crater increased on 21 December with more frequent explosions; a total of 423 explosions were recorded during 21-28 December. At 0248 on 28 December a large eruptive event ejected large bombs 1.3 km SE of the crater and produced a plume that rose 200 m above the crater rim and entered weather clouds. The Alert Level was raised to 3 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 11-18 December. A total of five explosions were recorded, ejecting bombs up to 500 m away from the crater and producing gray-and-white plumes that rose 1.6 km above the crater rim. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 4-11 December. A total of 20 explosions were recorded, ejecting bombs up to 500 m away from the crater and producing gray-and-white plumes that rose 1.5 km above the crater rim. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 27 November-4 December. A total of 17 explosions were recorded, ejecting bombs up to 600 m away from the crater and producing gray-and-white plumes that rose 1.5 km above the crater rim. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 20-27 November. A total of 34 explosions were recorded, ejecting bombs up to 700 m away from the crater and producing gray-and-white plumes that rose 1.4 km above the crater rim. The Tokyo VAAC noted that ash plumes drifted S and SE. Ashfall was reported in Toshima village (4 km SSW). Crater incandescence was visible from the morning of 20 November through 22 November. The Alert Level remained at 2 (on a 5-level scale).
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 13-20 November. A total of 18 explosions were recorded, ejecting bombs as far as 400 m from the crater and producing gray-and-white plumes that rose 1.5 km above the crater rim. Ashfall was reported in Toshima village (4 km SSW) on 13 November. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 6-13 November. A total of 35 explosions were recorded, ejecting bombs up to 700 m from the crater and producing gray-and-white plumes that rose 1.8 km above the crater rim. Ashfall was periodically reported in Toshima village (4 km SSW). The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 30 October-6 November. A total of 24 explosions were recorded, ejecting bombs 400 m from the crater and producing a gray ash plume that rose 1.5 km above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 23-30 October. Eight explosions were recorded; an explosion at 0204 on 24 October ejected bombs 300 m from the crater and an explosion at 1710 on 28 October produced an ash plume that rose 2 km above the crater rim. Ashfall was periodically reported in Toshima village (4 km SSW). The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 16-23 October. Three explosions were recorded; an explosion at 0439 on 17 October produced a grayish-white ash plume that rose 1.4 km above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 9-16 October. Four explosions were recorded during 12-14 October; an explosion at 0100 on 13 October ejected bombs 400 m from the crater and an explosion at 0313 on 14 October produced an ash plume that rose 1.2 km above the crater rim. Ashfall was periodically reported in Toshima village, 4 km SSW. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 2-9 October. Ashfall was occasionally reported in Toshima village, 4 km SSW. An explosion at 1155 on 8 October generated an ash plume that rose more than 700 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence at Suwanosejima’s Ontake Crater during 25 September-2 October. Eruptive activity was intermittently recorded along with nine explosions. Ashfall was periodically reported in Toshima village, 4 km SSW. An explosion at 0822 on 26 September generated a gray-white ash plume that rose 2 km above the crater rim. At 2028 on 27 September an explosion ejected blocks 400 m from the crater. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence at Suwanosejima’s Ontake Crater during 18-25 September. An explosion at 0923 on 25 September generated a gray-white ash plume that rose 600 m above the crater rim and disappeared into weather clouds. Ashfall was reported in Toshima village, 4 km SSW. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence at Suwanosejima’s Ontake Crater during 11-18 September. An explosion at 0155 on 15 September generated an ash plume that rose 1.5 km above the crater rim and ejected large rocks as far as 400 m from the crater. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported periodic nighttime incandescence and three explosions at Suwanosejima’s Ontake Crater during 4-11 September. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported periodic nighttime incandescence at Suwanosejima’s Ontake Crater during 28 August-4 September, and there was a total of 11 eruptions. An eruption at 0234 on 4 September generated a grayish white ash plume that rose 1.3 km above the crater rim before entering weather clouds. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported nighttime incandescence at Suwanosejima’s Ontake Crater during 14-24 August. Occasional eruptive events and about 12 explosions were recorded during 18-24 August. One of the explosions, detected at 0452 on 21 August, ejected blocks as far as 600 m from the crater. An explosion at 1449 that same day generated a grayish white ash plume that rose more than 2 km above the crater rim. Ashfall was noted in Toshima village (4 km SSW) on 21 August. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported occasional eruptive events, three explosions, and occasional nighttime incandescence at Suwanosejima’s Ontake Crater during 31 July-7 August. An explosion at 1553 on 1 August generated an ash plume that rose 1.8 km above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that nighttime incandescence at Suwanosejima’s Ontake Crater was occasionally visible during 24-31 July. Occasional eruptive events were recorded. An explosion at 1200 on 27 July generated a gray plume that rose as high as 2 km above the crater rim. The Tokyo VAAC reported that during 1-3 August ash plumes rose to 1.8-2.4 km (6,000-8,000 ft) a.s.l. and drifted NW and W. The Alert Level remained at 2 (on a 5-level scale).
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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JMA reported that nighttime incandescence at Suwanosejima’s Ontake Crater was occasionally visible during 17-24 July. An explosion at 2247 on 22 July generated a gray plume that rose as high as 1.2 km above the crater rim and ejected large rocks as far as 300 m from the crater. The Tokyo VAAC reported that during 25-27 July ash plumes rose to 1.8-2.7 km (6,000-9,000 ft) a.s.l. (1-1.9 km above the crater rim) and drifted NW, N, NE. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that nighttime incandescence at Suwanosejima’s Ontake Crater was occasionally visible during 10-17 July. Occasional eruptive events were recorded along with three explosions. One of them, recorded at 1630 on 12 July, generated a gray-white plume that rose as high as 1.5 km above the crater rim and entered a weather cloud. An explosion at 2006 on 15 July ejected large rocks as far as 300 m from the crater. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that nighttime incandescence at Suwanosejima’s Ontake Crater was occasionally visible during 3-10 July. An eruptive event on 5 July generated a grayish white plume that rose 800 m above the crater rim and ejected material 300 m from the crater. The Tokyo VAAC noted that an ash plume rose to 2.1 km (7,000 ft) a.s.l. and drifted NE on 12 July based on satellite images and JMA information. The Alert Level remained at 2 (on a 5-level scale).
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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JMA reported that nighttime incandescence at Suwanosejima’s Ontake Crater was occasionally visible during 26 June-3 July. An eruptive event on 2 July generated a grayish white plume that rose 1 km above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that nighttime incandescence at Suwanosejima’s Ontake Crater was occasionally visible during 19-26 June. Very small eruptive events were occasionally recorded with plumes rising as high as 900 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that nighttime incandescence at Suwanosejima’s Ontake Crater was occasionally visible during 12-19 June. An explosion was recorded on 18 June, though inclement weather conditions prevented visual confirmation. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that nighttime incandescence at Suwanosejima’s Ontake Crater was occasionally visible during 5-12 June. An eruptive event on 5 June produced gray-white plume rose as high as 1 km above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that nighttime incandescence at Suwanosejima’s Ontake Crater was occasionally visible during 29 May-5 June. An explosion at 0210 on 29 May produced an off-white plume that rose as high as 500 m above the crater rim. Large rocks were ejected 200 m above the rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that nighttime incandescence at Suwanosejima’s Ontake Crater was visible during 22-29 May. Five explosions were recorded, producing plumes that rose as high as 700 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that nighttime incandescence at Suwanosejima’s Ontake Crater was visible during 15-22 May. Two explosions were recorded on 21 May, producing plumes that rose as high as 900 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 1-8 May explosions occurred twice a day at Suwanosejima’s Ontake Crater and produced plumes that rose as high as 1 km above the crater rim. Material was ejected 400 m from the crater. Crater incandescence was visible nightly. Rumbling sounds were noted in a village 4 km SSW. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that at 0432 on 28 April an eruption at Suwanosejima’s Ontake Crater produced a plume that rose 1.6 km above the crater rim and ejected blocks as far as 800 m from the crater. An explosion at 1214 on 29 April caused glass in an office building to vibrate in a village 4 km SSW. There was a total of 64 and 50 explosions recorded on 28 and 29 April, respectively; two explosions were detected on 30 April and one on 1 May. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 17-24 April incandescence from Suwanosejima’s Ontake Crater was visible nightly. Small eruptions occasionally occurred, along with an explosion on 24 April, producing gray-white plumes that rose as high as 600 m above the crater rim and ejected material as far as 600 m from the crater. Rumbling sounds were noted in a village 4 km SSW. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 10-17 April incandescence from Suwanosejima’s Ontake Crater was visible nightly. Small eruptions occasionally occurred, along with an explosion on 15 April, producing gray-white plumes that rose as high as 1 km above the crater rim; plumes drifted N on 15 April. Rumbling sounds were noted in a village 4 km SSW. The Alert Level remained at 2 (on a 5-level scale).
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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JMA reported that during 3-10 April incandescence from Suwanosejima’s Ontake Crater was visible nightly. Small eruptions occasionally occurred, producing gray-white plumes that rose as high as 900 m above the crater rim; rumbling sounds were noted in a village 4 km SSW. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 27 March-3 April incandescence from Suwanosejima’s Ontake Crater was visible nightly. An eruptive event on 2 April produced a grayish-white plume that rose 800 m above the crater rim; ringing sounds were noted in a village 4 km SSW. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 19-27 March incandescence from Suwanosejima’s Ontake Crater was visible nightly. One explosion was recorded on 23 March and eruptive events were detected during 23-24 March; ringing sounds were noted in a village 4 km SSW. Gray-white plumes rose 700 m above the crater rim on 24 March. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 13-19 March incandescence from Suwanosejima’s Ontake Crater was visible nightly. On 14 March an ash plume rose 400 m above the crater rim. On 23 March the Tokyo VAAC reported that an explosion produced an ash plume that rose to an altitude of 0.9 km (3,000 ft) a.s.l., or 120 m above the summit, and drifted SE. The Alert Level remained at 2 (on a 5-level scale).
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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JMA reported that during 28 February-6 March incandescence from Suwanosejima’s Ontake Crater was visible nightly. Occasional eruptive events generated ash plumes that rose as high as 900 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 28 February-6 March incandescence from Suwanosejima’s Ontake Crater was visible nightly. Occasional eruptive events and two explosions were recorded; ash plumes rose as high as 900 m above the crater rim. Occasional eruption sounds were reported in a village 4 km SSW on 3 March. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 21-28 February incandescence from Suwanosejima’s Ontake Crater was visible nightly. Occasional eruptive events and two explosions were recorded; ash plumes rose as high as 1.2 km above the crater rim. Blocks were ejected onto the flanks during 23-24 February. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 14-21 February incandescence from Suwanosejima’s Ontake Crater was visible nightly. An eruption on 19 February produced a grayish-white ash plume that rose 1.6 km above the crater rim. Ashfall was reported in Toshima village, 4 km SSW. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 7-14 February incandescence from Suwanosejima’s Ontake Crater was visible nightly. Very small eruptions during 9-10 February produced ash plumes that rose 700 m above the crater rim. Rumbling and ashfall was reported in a village 4 km SSW. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that white plumes rose as high as 700 m above the rim of Suwanosejima’s Ontake Crater during 17-24 January. Crater incandescence was visible nightly. No changes in crater morphology were observed during an overflight on 21 January compared to 21 February 2019 observations; white plumes rose 400 m above the rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that Suwanosejima’s seismic network recorded an explosion at Ontake Crater on 10 January and occasional small eruptive events during 12-17 January. Plumes rose as high as 1 km above the crater rim. Residents of Toshima Village (4 km SSW) reported ashfall and explosion and rumbling sounds. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA recorded 13 explosions at Suwanosejima’s Ontake Crater during 3-10 January. Eruption plumes rose as high as 1.4 km above the crater rim and material was ejected as far as 600 m from the crater. Explosion and rumbling sounds, as well as ashfall, were reported in areas 4 km SSW. Crater incandescence was visible at night. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that on 28 December a very small eruptive event was recorded at Suwanosejima’s Ontake Crater. Explosions occurred on 31 December and 3 January; the latter explosion produced a gray ash plume that rose 800 m above the crater rim and entered the weather clouds. Crater incandescence was visible at night during 28 Deecmber-3 January. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima’s Ontake Crater was visible during 20-27 December. Eruptive events generated grayish plumes that rose as high as 800 m above the crater rim and material was ejected as far as 600 m from the crater; there were nine explosions recorded during 25-26 December. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima’s Ontake Crater was visible during 15-22 November. Eruptive events generated grayish white plumes that rose as high as 900 m above the crater rim. Ashfall was reported in Toshima Village (4 km SSW) during 19-20 November. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima’s Ontake Crater was visible during 8-15 November. Occasional eruptive events during 13-15 November generated grayish white plumes that rose as high as 1.5 km above the crater rim. Ashfall was reported in Toshima Village (4 km SSW) on 14 November. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that incandescence at Suwanosejima’s Ontake Crater was visible during 1-8 November. Very small eruptive events on 5 and 7 November generated grayish white plumes that rose 900 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that at 1225 on 19 October a very small eruptive event at Suwanosejima’s Ontake Crater generated a gray plume that rose 300 m above the crater rim. A small amount of ash fell in Toshima, 4 km SW. Very small eruptions during 29-30 October generated grayish-white plumes that rose 800 m. Ashfall was reported in Toshima on 29 October. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 20-27 September white plumes rose 800 m above the rim of Suwanosejima’s Ontake Crater and crater incandescence was visible at night. The Alert Level remained at 2 (on a 5-level scale).
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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JMA reported that at 0704 on 16 September a very small eruptive event at Suwanosejima’s Ontake Crater generated a plume that rose 400 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 30 August-6 September white plumes rose 1.2 km above the rim of Suwanosejima’s Ontake Crater and crater incandescence was visible at night. According to the Tokyo VAAC an ash plume rose 2.4 km (8,000 ft) a.s.l. and drifted W on 10 September. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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The Tokyo VAAC reported that on 26 August a plume from Suwanosejima was visible in satellite images rising to 2.1 km (7,000 ft) a.s.l. The Alert Level remained at 2 (on a 5-level scale).
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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JMA reported that volcanic earthquakes began to be detected at Suwanosejima on 4 August and volcanic tremors were occasionally recorded during 4-9 August. Four eruptive events occurred at Ontake Crater on 5 August and one on 6 August. Large blocks were ejected as far as 400 m and ash plumes rose as high as 1.5 km above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that at 2331 on 1 August an explosion at Suwanosejima’s Ontake Crater ejected blocks 400 m from the crater. Weather clouds prevented visual confirmation of an ash plume. Crater incandescence was sometimes visible at night. The number of volcanic earthquakes increased on 4 August and four explosions were recorded on 5 August. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was occasionally visible at night during 24-31 May. An eruption at 1629 on 30 May generated a plume that rose 1.1 km above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible at night during 3-10 May. A very small eruption on 5 May generated a plume that rose 500 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible at night during 15-22 March. Small events were occasionally recorded, generating plumes that rose as high as 600 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible at night during 8-15 March. Small events were occasionally recorded, generating plumes that rose as high as 400 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible at night during 1-8 March. Small events were occasionally recorded, generating plumes that rose as high as 600 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible at night during 22 February-1 March. Small events were occasionally recorded, generating plumes that rose as high as 900 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible at night during 15-22 February. Small events were occasionally recorded, generating plumes that rose as high as 900 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that crater incandescence at Suwanosejima’s Ontake Crater was visible during 1-8 February. Were small events were occasionally recorded, generating plumes that rose as high as 900 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that four explosions at Suwanosejima’s Ontake Crater were recorded during 22-30 November. The highest ash plume rose 2 km, and material was ejected 300 m from the crater. Ashfall was reported in an area 4 km SSW on 23 November. Crater incandescence was visible at night. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that 16 explosions at Suwanosejima’s Ontake Crater were recorded during 16-22 November. The highest ash plume rose 2 km, and material was ejected 300 m from the crater. Ashfall was reported in an area 4 km SSW on 17 November. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that four explosions at Suwanosejima’s Ontake Crater were recorded during 9-16 November. The highest ash plume rose 2 km, the first time a plume from Ontake Crater rose that high since 4 April. Material was ejected 700 m from the crater. Ashfall was reported in an area 4 km SSW on 15 November. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that an explosion at Suwanosejima’s Ontake Crater was recorded at 0428 on 9 November. A plume could not be confirmed because weather clouds obscured views, but large pieces of pumice were observed being ejected 700 m S. Explosions had not been recorded since 2 June. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 12-13 September eruptive events at Suwanosejima’s Ontake Crater generated plumes that rose 1.1 km above the crater rim. Tremor increased, and nighttime crater incandescence was also visible. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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JMA reported that during 3-10 August white plumes rose as high as 1 km above the rim of Suwanosejima’s Ontake Crater, and incandescence from the crater was visible at night. The Alert Level remained at 2 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
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Based on JMA notices and satellite data, the Tokyo VAAC reported an explosion at Suwanosejima on 2 June.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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The Tokyo VAAC reported that explosions occurred at Suwanosejima on 15 May, based on information from JMA.
Source: Japan Meteorological Agency (JMA)
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The Tokyo VAAC reported explosions at Suwanosejima on 2 and 4 May, based on JMA notices and satellite data.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite data, the Tokyo VAAC reported an explosion at Suwanosejima on 24 April, and that events during 27-29 April produced plumes that rose 1.2-2.1 km (4,000-7,000 ft) a.s.l. and drifted in multiple directions.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite data, the Tokyo VAAC reported that during 4-6 and 9 April explosions at Suwanosejima produced plumes that rose 1.2-2.4 km (4,000-8,000 ft) a.s.l. and drifted N, NE, and E.
Source: Japan Meteorological Agency (JMA)
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Based on JMA notices and satellite data, the Tokyo VAAC reported that during 28-30 March and 2 April explosions at Suwanosejima produced plumes that rose 1.2-2.7 km (4,000-9,000 ft) a.s.l. and drifted NE, NW, W, SW, and S.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite data, the Tokyo VAAC reported that during 22-23 and 25-26 March events at Suwanosejima produced plumes that rose 1.2-2.4 km (4,000-8,000 ft) a.s.l. and drifted SE and NW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite data, the Tokyo VAAC reported that on 17 March an eruption at Suwanosejima produced a plume that rose 1.8 km (6,000 ft) a.s.l. and drifted W.
Source: Japan Meteorological Agency (JMA)
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Based on JMA notices and satellite data, the Tokyo VAAC reported that on 15 January an eruption at Suwanosejima produced a plume that rose 1.8 km (6,000 ft) a.s.l. and drifted NW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite data, the Tokyo VAAC reported that on 10 November an event at Suwanosejima produced a plume that rose 1.8 km (6,000 ft) a.s.l. and drifted NW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite data, the Tokyo VAAC reported explosions at Suwanosejima during 31 October, and 1, 3, and 5 November; plumes rose 1.5 km (5,000 ft) a.s.l. and drifted NW and W.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite data, the Tokyo VAAC reported that on 11 October an explosion at Suwanosejima generated a plume that rose 2.7 km (9,000 ft) a.s.l. and drifted NE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported an explosion on 29 September which generated a plume that rose 2.4 km (8,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported explosions on 6 September generated plums that rose 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported explosions during 30 August-2 September.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 24-25 August ash plumes from Suwanosejima rose to altitudes of 2.1-3 km (7,000-10,000 ft) a.s.l. and drifted E and NE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices, the Tokyo VAAC reported explosions at Suwanosejima during 19-20 August.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 18-19 July ash plumes from Suwanosejima rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 2 July ash plumes from Suwanosejima rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. and drifted N.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 10 May plumes from Suwanosejima rose to an altitudes of 2.7 km (9,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 8 May plumes from Suwanosejima rose to altitudes of 1-2.1 km (3,000-7,000 ft) a.s.l. and drifted N and SW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 1 April an explosion at Suwanosejima generated a plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted E
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 28 March an explosion at Suwanosejima generated a plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 3-4 March explosions at Suwanosejima generated ash plumes that rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted SE
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported explosions at Suwanosejima during 27-28 February. Ash plumes rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SE on 28 February.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 9 February an explosion generated an ash plume from Suwanosejima that rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 26 January an ash plume from Suwanosejima rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 17 January an ash plume from Suwanosejima rose to an altitude of 1.2 km (4,000 ft) a.s.l. and drifted S.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 4-5 January ash plumes from Suwanosejima rose to altitudes of 1.2-1.8 km (4,000-6,000 ft) a.s.l. and drifted SE and W.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 17-18 December ash plumes from Suwanosejima rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted SE and SW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices, pilot observations, and satellite-image analyses, the Tokyo VAAC reported that explosions at Suwanosejima on 13 December generated ash plumes that rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted NE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported explosions on 23, 25, and 29 November. Ash plumes on 25 and 29 November rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted S and SW. On 29 November a pilot observed an ash plume that rose to an altitude of 3 km (10,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 16-17 November explosions at Suwanosejima generated ash plumes that rose to an altitude over 1.2 km (4,000 ft) a.s.l. and drifted S. During 20-21 November ash plumes rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 5-6 October explosions at Suwanosejima generated ash plumes that rose to altitudes of 1.2-2.1 km (4,000-7,000 ft) a.s.l. and drifted SE, S, and W.
Source: Japan Meteorological Agency (JMA)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 5-6 November events at Suwanosejima generated ash plumes that rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted E and SW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 6 October an explosion at Suwanosejima generated ash plumes that rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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The Tokyo VAAC reported an explosion at Suwanosejima on 15 September. An explosion on 17 September produced an ash plume that rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted W.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on a pilot observation and satellite data, the Tokyo VAAC reported that on 31 August ash plume from Suwanosejima rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 25-26 and 28-29 August explosions at Suwanosejima often generated ash plumes that rose to altitudes of 0.9-2.4 km (3,000-8,000 ft) a.s.l. and drifted W, SW, and SE.
Source: Japan Meteorological Agency (JMA)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 11-12 and 14 August ash plumes from Suwanosejima rose to altitudes of 1.8-2.7 km (6,000-9,000 ft) a.s.l. and drifted W and NW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 1-2 August ash plumes from Suwanosejima rose to altitudes of 1.5-3.4 km (5,000-11,000 ft) a.s.l. and drifted W and SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices, satellite-image analyses and pilot observations, the Tokyo VAAC reported that during 18-19 July ash plumes from Suwanosejima rose to altitudes of 1.8-2.7 km (6,000-9,000 ft) a.s.l. and drifted NE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 13 June ash plumes from Suwanosejima rose to altitudes of 1.8-2.7 km (6,000-9,000 ft) a.s.l. and drifted E.
Source: Japan Meteorological Agency (JMA)
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Based on JMA notices, the Tokyo VAAC reported that on 18 May an explosion at Suwanosejima generated an ash plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted W.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices, the Tokyo VAAC reported that during 4-5 May explosions at Suwanosejima generated ash plume that rose to altitudes of 1.5-2.1 km (5,000-7,000 ft) a.s.l. and drifted SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices, pilot observations, and satellite data, the Tokyo VAAC reported explosions at Suwanosejima during 20-21 April; ash plumes rose to altitudes of 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted N and NW on 20 April.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices, pilot observations, and satellite data, the Tokyo VAAC reported an explosion on 14 April, and ash plumes that rose to altitudes of 0.1-2.1 km (3,000-7,000 ft) a.s.l. and drifted W, E, SE, and S during 15 and 17-19 April.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite data, the Tokyo VAAC reported that during 21, 23-24, and 26 March explosions at Suwanosejima generated ash plumes that rose to altitudes of 1.2-2.4 km (4,000-8,000 ft) a.s.l. and drifted N, W, and SE. Ash emissions continued on 27 March.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 11 March an explosion at Suwanosejima generated a plume that rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SE.
Source: Japan Meteorological Agency (JMA)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that during 2-3 and 8 March explosions at Suwanosejima generated ash plumes that rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. and sometimes drifted SE. Explosions were also detected on 5 and 7 March.
Source: Japan Meteorological Agency (JMA)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported an explosion at Suwanosejima on 6 January.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 13 September ash plumes from Suwanosejima rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted SE.
Source: Japan Meteorological Agency (JMA)
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Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 21 August ash plumes from Suwanosejima rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted SE.
Source: Japan Meteorological Agency (JMA)
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Based on JMA notices, satellite-image analyses, and pilot observations, the Tokyo VAAC reported that ash plumes from Suwanosejima rose to altitudes of 2.1-3 km (7,000-10,000 ft) a.s.l. and drifted E, SW, and W during 30-31 July and 4 August. On 2 August an ash plume rose to an altitude of 4 km (13,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices, the Tokyo VAAC reported that explosions at Suwanose-jima during 24-25 April generated plumes that rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted N and SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices, the Tokyo VAAC reported that an eruption at Suwanose-jima on 13 April generated a plume that rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted N.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices, the Tokyo VAAC reported that during 11-12 and 14-15 February ash plumes from Suwanosejima rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices, the Tokyo VAAC reported an explosion from Suwanosejima on 25 January.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on a pilot observations and JMA notices, the Tokyo VAAC reported that on 5 January ash plumes from Suwanosejima rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted NE and SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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The Tokyo VAAC reported that on 14 December an explosion at Suwanosejima produced a plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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The Tokyo VAAC reported that on 7 December explosions at Suwanosejima produced plumes that rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted E and SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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The Tokyo VAAC reported that on 14 November an explosion at Suwanosejima produced a plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Tokyo VAAC released ash advisories for Suwanosejima during 3-4 and 9 September based on JMA reports. Ash drifted NE and N at 1,800-5,500 m (6,000-18,000 ft) a.s.l. on 3 September. On 4 September, an ash plume at 5,500 m (18,000 ft) a.s.l. was observed. JMA also reported a 2,100 m (7,000 ft) a.s.l. ash plume on 9 September at 2233.
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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During 28 August-1 September, the Tokyo VAAC reported eruptions at Suwanosejima. Ash plumes rose 1.8-2.7 km (6,000-9,000 ft) a.s.l. and drifted E, SE, S, and NE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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During 18-20 June, JMA reported explosions at Suwanosejima. Ash plumes were not visible in satellite images. Explosions occurred at 1346 on 18 June, 0834 on 19 June with a plume drifting E, and at 0033 on 20 June.
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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The Tokyo VAAC reported that on 29 April an explosion at Suwanosejima produced a plume that rose to an altitude of 1.2 km (4,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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The Tokyo VAAC reported an explosion from Suwanosejima on 19 February. Explosions during 23-24 February produced plumes that rose to an altitude of 1.8 km (6,000 ft) a.s.l. An ash plume on 24 February drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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The Tokyo VAAC reported explosions from Suwanosejima during 12-14 February. On 12 February a plume rose to an altitude of 1.2 km (4,000 ft) a.s.l. and drifted SE, and on 14 February a plume rose to an altitude of 1.8 km (6,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on JMA notices and pilot observations, the Tokyo VAAC reported that on 2 February ash plumes from Suwanosejima rose to altitudes of 1.8-3 km (6,000-10,000 ft) a.s.l. and drifted SE and SSE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that explosions from Suwanosejima on 24 January generated a plume that rose to an altitude 1.8 km (6,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that explosions from Suwanosejima during 8-9 January sometimes generated plumes that rose to an altitude 1.2 km (4,000 ft) a.s.l. and drifted NE and SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 1-3 and 6 January. Explosions during 1-2 January generated plumes that rose to altitudes 0.9-1.8 km (3,000-6,000 ft) a.s.l. and drifted SE. JMA noted that the Alert Level remained at 2 (on a scale of 1-5).
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 26-30 December. Explosions during 27-28 December generated plumes that rose to an altitude over 1.5 km (5,000 ft) a.s.l. and drifted SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an explosion from Suwanose-jima on 27 November generated a plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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According to the Tokyo VAAC, a pilot observed an ash plume from Suwanose-jima on 21 October. Based on information from JMA the VAAC noted that a plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted S that same day.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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According to the Tokyo VAAC, the JMA reported that on 12 September an eruption from Suwanose-jima generated an ash plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted NW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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According to the Tokyo VAAC, the JMA reported that during 5-6 September explosions from Suwanose-jima generated ash plumes that rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted NW and N.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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According to the Tokyo VAAC, the JMA reported that on 28 August pilots observed ash plumes from Suwanose-jima that rose to altitudes of 3-3.7 km (10,000-12,000 ft) a.s.l. and drifted E and NW. Explosions during 28-29 August generated ash plumes that rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted NE. Ash was detected in satellite images on 29 August, and explosions were detected on 30 August and 1 September.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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According to the Tokyo VAAC, the JMA reported explosions from Suwanose-jima during 26-27 August. Plumes rose to an altitude of 1.2 km (4,000 ft) a.s.l. on 27 August, and drifted NE and SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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According to the Tokyo VAAC, a pilot observed an ash plume from Suwanose-jima that rose to an altitude of 1.5 km (5,000 ft) a.s.l. Ash was not detected in satellite images.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on a pilot observation, the Tokyo VAAC reported that on 3 October an ash plume from Suwanose-jima drifted SW at altitude of 3 km (10,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 6 March. Details of a possible resulting plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 6 February. Details of a possible resulting plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 12 January. Details of a possible resulting plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on a pilot observation, the Tokyo VAAC reported that on 14 October an ash plume from Suwanose-jima rose to an altitude of 1.2 km (4,000 ft) a.s.l. and drifted SE. Ash was not detected in satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 12 September. That same day an eruption produced a plume that rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted W.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on a pilot observation, the Tokyo VAAC reported that on 14 July an ash plume from Suwanose-jima rose to an altitude of 3.7 km (12,000 ft) a.s.l. Ash was not detected in satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 3 May. Details of a possible resulting plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that explosions from Suwanose-jima on 12 April produced a plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 19-20 March. Details of a possible resulting plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 15 March. Details of a possible resulting plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 3 March. Details of a possible resulting plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 9 and 14 February. Details of a possible resulting plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on a pilot observation, the Tokyo VAAC reported that on 5 February an ash plume from Suwanose-jima rose to an altitude of 0.7 km (2,000 ft) a.s.l. and drifted S. Explosions during 5-7 February were noted by JMA.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 22-23 and 25 January. A plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted S on 23 January.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 12-13 and 15 January. A plume rose to an altitude of 1.2 km (4,000 ft) a.s.l. and drifted SE on 13 January.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima during 11-12 January. Details of a possible resulting plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 29 December. Details of a possible resulting plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 20 December. Details of possible a resulting plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 1-4 December. Plumes rose to an altitude of 1.2 km (4,000 ft) and drifted SE on 4 December.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 27 November-1 December. Plumes rose to a maximum altitude of 1.5 km (5,000 ft) on 29 November.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 18-23 November. Plumes rose to an altitude of 1.8 km (6,000 ft) on 18 November and to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted NE on 21 November.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 10 and 12 November. On 11 November a pilot reported an ash plume. A subsequent satellite image showed that the ash had dissipated. The next day, a pilot reported that an ash plume rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted S.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 26 October.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 16-17 October. A plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SE on 17 October.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 3-5 October. A plume drifted E on 5 October.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 22, 25, and 27-28 September. A pilot observed an ash plume on 22 September that rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted SE. JMA noted that plumes on 25 September rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 19-21 September. Details of possible resulting plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 11 September. Details of possible resulting plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 25 and 27 August. Details of possible resulting plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 21-24 August. Details of possible resulting plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that explosions from Suwanose-jima produced plumes that rose to an altitude of 1.5 km (5,000 ft) a.s.l. on 23 July and to an altitude of 2.4 km (8,000 ft) a.s.l. on 26 July. Plumes drifted NW and W, respectively.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 17 and 19 July. Details of possible resulting plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that explosions from Suwanose-jima during 15-16 May produced plumes that rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted N and NW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 29 April, and during 1 and 4-5 May. Details of possible resulting plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 2 April. Details of possible resulting plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 29 March. Details of possible resulting plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 17-19 and 21-22 February. Plumes occasionally rose to altitudes of 1.2-1.8 km (4,000-6,000 ft) a.s.l. and drifted E and SE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 11-16 February. Details of possible resulting plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 5-6 and 9 February. Details of possible resulting emissions were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 27 January-2 February. On 27 January, plumes rose to altitudes of 1.2-1.5 km (4,000-5,000 ft) a.s.l. and drifted W. Plumes rose to an altitude of 1.8 km (6,000 ft) a.s.l. on 29 January.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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During 29-30 December 2009, a visitor to Suwanose-jima observed and photographed multiple Strombolian explosions and ash eruptions from Otake crater. Based on information from JMA, the Tokyo VAAC reported explosions during 22-26 January. On 24 and 26 January, plumes rose to altitudes of 1.2-1.5 km (4,000-5,000 ft) a.s.l.
Sources: Tokyo Volcanic Ash Advisory Center (VAAC); Richard Roscoe, Photo Volcanica
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 13 and 16-17 January. Details of possible resulting emissions were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 6-9 and 11 January. Plumes rose to an altitude of 1.8 km (6,000 ft) a.s.l. on 6 and 9 January and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 30 December-2 January and 4-5 January. Plumes rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. on 2 and 4 January, and drifted NE and E on 4 January.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 24, 26, and 28-29 December. Details of possible resulting emissions were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported eruptions from Suwanose-jima during 17-20 and 22 December. A plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. on 22 December.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported eruptions from Suwanose-jima on 14 and 15 December. Plumes rose to altitudes of 1.2-1.5 km (4,000-5,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima during 5-6 December. Details of possible resulting emissions were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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The Tokyo VAAC reported that on 26 November an ash plume from Suwanose-jima was seen by a pilot 65 km S drifting NE at an altitude of 3 km (10,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 18 November. Details of possible resulting emissions were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 12 and 16 November. Details of possible resulting emissions were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that explosions from Suwanose-jima during 4-5 November produced plumes that rose to altitudes of 1.2-1.8 km (4,000-6,000 ft) a.s.l. and drifted SW and W. An explosion was also reported on 6 November.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 30 October and 2 November. Details of possible resulting emissions were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 10 and 11 October. A plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. on 10 October.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 1 October. A plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. and rifted W.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA and pilot observations, the Tokyo VAAC reported that on 17 September ash from Suwanose-jima drifted S. On 19 September, an ash plume rose to an altitude of 1.5 km (5,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 13-14 September. Details of possible resulting ash plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 3-7 September. Details of possible resulting ash plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that explosions from Suwanose-jima during 27-29 August sometimes produced plumes that rose to altitudes of 1.5-2.4 km (5,000-8,000 ft) a.s.l. and drifted W.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that explosions from Suwanose-jima during 16-17 August produced plumes that rose to an altitude of 1.8 km (6,000 ft) a.s.l. Plumes drifted E on 16 August.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 10 August. Details of a possible resultant ash plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 5 August. Details of possible resultant ash plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 23-24 July. Details of possible resultant ash plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on a pilot observation, the Tokyo VAAC reported that on 15 July an ash plume from Suwanose-jima rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted NE. Eruptions reported by the JMA during 16-17 July produced plumes that rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted NE and W.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 6 July. Details of a possible resultant ash plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 16 June. Details of a possible resultant ash plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on analysis of satellite imagery and pilot observations, the Tokyo VAAC reported that on 25 May an ash plume from Suwanose-jima rose to an altitude of 1.5 km (5,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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The Tokyo VAAC reported an explosion from Suwanose-jima on13 May, as stated by JMA. Details of possible resultant ash plumes were not reported. Based on analysis of satellite imagery and a pilot observation, the VAAC also reported that on 17 May an ash plume rose to an altitude of 2.1 km (7,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 7-9 and 12 May. Details of possible resultant ash plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that eruptions from Suwanose-jima during 29 April-1 May produced plumes that rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. Plumes drifted W on 30 April and 1 May.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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The Tokyo VAAC reported that a pilot saw an ash plume from Suwanose-jima on 22 April. JMA reported that an eruption the next day produced ash plumes to altitudes of 1.2-1.5 km (4,000-5,000 ft) a.s.l. and drifted E and S. On 27 April, an explosion was reported but details of a possible resultant ash plume were not. On 28 April, explosions produced plumes that rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 21 April. Details of possible resultant ash plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 8 and 10 April. Details of possible resultant ash plumes on either day were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 6 April.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 28 March. JMA reported three explosions on 30 March. Details of possible resultant ash plumes on either day were not reported.
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that on 15 and 16 March eruptions from Suwanose-jima produced plumes that rose to an altitude of 1.5 km (5,000 ft) a.s.l. Plumes drifted E on 15 March.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported multiple explosions from Suwanose-jima on 6 March. Details of possible resultant ash plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported multiple explosions from Suwanose-jima during 26 February-1 March. On 1 March, resultant plumes rose to altitudes of 1.2-1.5 km (4,000-5,000 ft) a.s.l. and drifted E. On 2 March, an eruption produced a plume to an altitude of 1.5 km (5,000 ft) a.s.l. An explosion was reported on 3 March.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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JMA reported that Suwanose-jima erupted explosively on 18 February; a colored plume rose 400 m above the crater and drifted E. Two explosive eruptions occurred the next day. Based on information from JMA, the Tokyo VAAC reported explosions on 20 and 21 February. Details of possible resultant ash plumes were not reported.
Sources: Japan Meteorological Agency (JMA); Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 21 January. Details of a possible resultant ash plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 9 January.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an eruption from Suwanose-jima on 3 January. A plume rose to an altitude of 1.2 km (4,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 26-28 and 30 December. Plumes rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. during 27-28 December.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that during 17 and 19-20 December explosions or eruptions from Suwanose-jima produced plumes to an altitude of 1.5 km (5,000 ft) a.s.l. Plumes drifted E on 17 and 19 December.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, analysis of satellite imagery, and pilot reports, the Tokyo VAAC reported explosions or eruptions from Suwanose-jima during 10-12 and 14-16 December. Plumes rose to altitudes of 0.9-1.8 km (3,000-6,000 ft) a.s.l. and drifted E. Details of a possible ash plume on 14 and 16 December were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an eruption from Suwanose-jima on 21 November. A plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted E. An explosion was reported on 25 November.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on analysis of satellite imagery and information from JMA, the Tokyo VAAC reported multiple explosions or eruptions from Suwanose-jima during 12-16 November. Occasional plumes rose to altitudes of 1.5-2.1 km (5,000-7,000 ft) a.s.l. during 13-15 November.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on pilot observations and analysis of satellite imagery, the Tokyo VAAC reported that on 5 November an ash plume from Suwanose-jima rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted NE. The JMA indicated that during 7-8 November explosion or eruption plumes rose to altitudes of 1.2-1.8 km (4,000-6,000 ft) a.s.l. and drifted E. An explosion was reported on 12 November.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that during 29-30 October and 3 November Suwanose-jima produced explosion or eruption plumes that rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted E. Explosions were reported on 31 October and 1 November, but details of possible ash plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that Suwanose-jima produced explosion or eruption plumes that rose to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted W and E during 21, 23, 25-26, and 28 October.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that explosions from Suwanose-jima during 16 and 18-20 October produced plumes that rose to altitudes of 1.2-2.4 km (4,000-8,000 ft) a.s.l. and drifted W.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on reports from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 9 and 11 October. The altitude and direction of a possible resultant plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on reports from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 1, 3, 7, and 8 October. Plumes rose straight up to an altitude of 2.1 km (7,000 ft) a.s.l. on 8 October. The altitude and direction of plumes were not reported for the other days.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on reports from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 25-26 and 28-29 September. Resultant plumes rose to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted NE, E, and SW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on reports from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 5-7 September. Resultant plumes rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. Plumes drifted E on 5 September.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on reports from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 24-26 August. Resultant plumes rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. during 25-26 August.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on reports from JMA, the Tokyo VAAC reported that on 7 August an eruption plume from Suwanose-jima rose to an altitude of 1.2 km (4,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on pilot reports, the Tokyo VAAC reported that on 30 July an ash plume from Suwanose-jima rose to an altitude of 0.6 km (2,000 ft) a.s.l. and drifted S.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an explosion from Suwanose-jima occurred on 17 June. The altitude and direction of a possible resultant plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an explosion from Suwanose-jima occurred on 16 April. The altitude and direction of a possible resultant plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an explosion from Suwanose-jima occurred on 22 March. The altitude and direction of a possible resultant plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an eruption plume from Suwanose-jima rose to an altitude of 1.8 km (6,000 ft) a.s.l. on 7 February and drifted E. Explosions were also noted on 8, 9, and 13 February, but altitude and direction of possible plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that eruption plumes from Suwanose-jima rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. during 14-17 December and drifted E. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that eruption plumes from Suwanose-jima rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. on 10 December and drifted W. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that eruption plumes from Suwanose-jima rose to altitudes of 1.2-1.8 km (4,000-6,000 ft) a.s.l. during 29 November-2 December and drifted E. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that eruption plumes from Suwanose-jima rose to an altitude of 1.5 km (5,000 ft) a.s.l. during 26-28 October and drifted E and W. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an eruption plume from Suwanose-jima rose to an altitude of 1.5 km (5,000 ft) a.s.l. on 22 October and drifted W. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an eruption plume from Suwanose-jima rose to an altitude of 1.5 km (5,000 ft) a.s.l. on 16 October and drifted E. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 17 September. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA and a pilot report, the Tokyo VAAC reported that an ash plume from Suwanose-jima rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SW on 26 July. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 8 May. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 30 March and 2 April. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 17 March. Ash was not seen on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that on 2 March an eruption plume from Suwanose-jima rose to an altitude of 1.2 km (4,000 ft) a.s.l. and drifted W.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA and satellite imagery, the Tokyo VAAC reported that an explosion from Suwanose-jima produced eruption plumes during 19-20 February. The altitude and direction of the plumes were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA and satellite imagery, the Tokyo VAAC reported that an explosion from Suwanose-jima produced an eruption plume during 7 February. The altitude and direction of the plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA and satellite imagery, the Tokyo VAAC reported that an explosion from Suwanose-jima produced an eruption plume during 5-6 February. The altitude and direction of the plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an eruption plume from Suwanose-jima on 28 January. The altitude and direction of the plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an eruption plume from Suwanose-jima on 9 January. The altitude and direction of the plume were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an eruption from Suwanose-jima occurred on 19 December.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that on 17 November an eruption plume from Suwanose-jima rose straight up to an altitude of 2.1 km (7,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that on 9 November an eruption plume from Suwanose-jima reached an altitude of 1.5 km (5,000 ft) a.s.l. and drifted W.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on satellite imagery and information from JMA, the Tokyo VAAC reported that during 4-6 November eruption plumes from Suwanose-jima reached altitudes of 1.2 km (4,000 ft) a.s.l. The plumes drifted E and SW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that on 27 and 28 October, ash plumes from Suwanose-jima reached altitudes of 1.8 km (6,000 ft) a.s.l. Plumes drifted E on 28 October.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 18 October.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA and a pilot report, the Tokyo VAAC reported that on 14, 16, and 17 October, ash plumes from Suwanose-jima reached altitudes of 3 km (10,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported an explosion from Suwanose-jima on 6 October.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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On 20 September the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite caught Suwanose-jima in the process of emitting volcanic ash and steam. The volcano's emissions blew N, gradually fanning out over the ocean, with a grayish tinge that distinguished it from nearby white clouds. Aviation ash advisories for this eruption issued by the Tokyo VAAC based on satellite imagery, pilot reports, and JMA, noted that the plume rose to 2.1 km (7,000 ft) a.s.l. and extended about 80 km N.
Sources: Tokyo Volcanic Ash Advisory Center (VAAC); NASA Earth Observatory
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Based on information from JMA and a pilot report, the Tokyo VAAC reported on 19 September that ash plumes from Suwanose-jima reached altitudes of 3.4 km (11,000 ft) a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that explosions from Suwanose-jima produced eruption plumes that rose straight up to 1.8 km (6,000 ft) a.s.l. on 26 August. On 28 August, eruption plumes rose to altitudes of 1.5 km (5,000 ft) a.s.l. and drifted E. Ash was not identified on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 11-14 August. The resulting plumes reached maximum altitudes of 1.8 km (6,000 ft) a.s.l. and drifted N and W. Ash was not identified on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima during 26-30 July. The resulting plumes reached maximum altitudes of 1.8 km (6,000 ft) a.s.l. and drifted N. Ash was not identified on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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A pilot observed an ash plume from Suwanose-jima on 16 July that reached an altitude of 1.8 km (6,000 ft) a.s.l. and drifted N. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported on 30 June that a small plume from Suwanose-jima reached an altitude of 1.2 km (4,000 ft) a.s.l. and drifted NE.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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A pilot observed ash from Suwanose-jima on 7 June at an altitude of 2.4 km (8,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA and an aircraft report, the Tokyo VAAC reported that ash from Suwanose-jima was visible at a height of ~1.5 km (5,000 ft) a.s.l. on 16 April.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that several explosions occurred at Suwanose-jima during 2-7 March. The highest plume reached ~1.8 km (6,000 ft) a.s.l. on 5 March.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that during 22-24 February several small eruptions occurred at Suwanose-jima. The highest rising plume reached ~3 km (10,000 ft) a.s.l. after an eruption on 23 February.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that several explosions occurred at Suwanose-jima during 6-7 February. A resultant plume from an explosion on the 6th rose to 1.2 km (4,000 ft) a.s.l. and extended NW.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that explosions occurred at Suwanose-jima on 1 and 10 January. An explosion on 10 January produced an ash plume to a height of ~1.8 km (6,000 ft) a.s.l. The heights of ash clouds from other explosions were not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an emission from Suwanose-jima on 22 September reached a height of ~1.8 km (6,000 ft) a.s.l. and drifted W. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that small eruptions at Suwanose-jima on 11 and 12 August produced ash plumes to a height of ~3.4 km (11,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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A pilot observed ash from Suwanose-jima on 28 July at a height of 2.4 km (~8,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an explosion occurred at Suwanose-jima on 6 July at 1400. The height of the resultant ash cloud was not reported.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that during 1-6 June several explosions at Suwanose-jima produced ash clouds. The only known height of an ash cloud was ~1.8 km (5,900 ft) a.s.l. from an explosion on 1 June.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that several explosions occurred at Suwanose-jima during 26-31 May. The highest reported plume rose to ~2.1 km (~7,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an eruption at Suwanose-jima on April 26 produced a plume to 1.2 km (4,000 ft) a.s.l. that extended E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an explosion at Suwanose-jima on 9 March produced an ash plume to a height of ~1.8 km a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that emissions from Suwanose-jima on 6 and 8 March produced ash plumes that rose to 1.5 and 1.2 km a.s.l., respectively.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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On 29 December, the Tokyo VAAC reported an eruption at Suwanose-jima that produced an ash plume to ~1.2 km a.s.l. Eruptions were also reported on 1 and 4 January, but no plumes were visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that eruptions at Suwanose-jima produced ash plumes to unknown heights on 22, 24, 25, and 27 December. The plumes were not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an eruption at Suwanose-jima on 20 December produced a SE-drifting plume to ~1.8 km a.s.l. Also, on 21 December an eruption produced a SE-drifting ash plume to an unknown height.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an eruption occurred at Suwanose-jima on 30 November at 1607. The eruption produced a plume to a height of ~1.2 km.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that several explosions occurred at Suwanose-jima during 30 June to 5 July. The highest rising plume reached ~1.9 km a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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An eruption at Suwanose-jima on 9 June at 1003 produced an ash plume visible on satellite imagery at a height of ~1.8 km a.s.l., extending E. Another explosion at 1300 that day produced an ash plume that reached an unknown height.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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On 7 June Suwanose-jima erupted, producing a plume to ~2 km a.s.l. that extended E. Eruptions continued through 8 June with at least one explosion producing a gas-and-ash plume to ~2 km a.s.l. that also drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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According to the Tokyo VAAC, ash emitted from Suwanose-jima was reported on 28 April at a height of ~3 km a.s.l. extending SE. No ash was visible on satellite imagery. JMA reported that an explosion occurred on 1 May at 0906, but it was not known if an ash cloud was produced.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from the Japanese Meteorological Agency, the Tokyo VAAC reported that explosions at Suwanose-jima on 21 and 22 January produced ash plumes to unknown heights.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that on 2 and 4 January small explosions occurred at Suwanose-jima producing ash plumes to unknown heights.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that several small ash emissions from Suwanose-jima on 27 and 28 December rose to unknown heights. Ash from an eruption on 28 December at 0820 reached a height of ~1.5 km a.s.l. and drifted E.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from the Japanese Meteorological Agency, the Tokyo VAAC reported that an explosion at Suwanose-jima on 21 December at 1828 produced a plume to an unknown height.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Based on information from JMA, the Tokyo VAAC reported that an explosion at Suwanose-jima on 15 December at 1946 produced a plume to an unknown height.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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Activity at Suwanose-jima was relatively low from 26 August until 12 September. On the 12th explosive eruptions began to occur frequently. According to the Suwanose-jima office of Toshima village, rumbling was intermittently heard about 4 km SSW of the summit and small amounts of ash fell. Explosions continued to occur until at least 13 September.
Source: Japan Meteorological Agency (JMA) via the Volcano Research Center
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Eruptive activity began to decline at Suwanose-jima in comparison to the previous week. Periods of volcanic tremor occurred on the 19th and 20th. According to the Suwanose-jima office of Toshima Village, rumbling sounds were not as strong as those of the previous week, but were sometimes accompanied by the sounds of large explosions on the 20th. Small amounts of ash fell in inhabited areas about 4 km SSW of the summit on the 20th and 21st. On the afternoon of the 20th ash also fell in Naze city on Amami-oshima Island, about 140 km S of Suwanose-jima. Aerial inspections conducted during the report period by the staff of Kagoshima Meteorological Observatory revealed that an ash-rich cloud rose 1.5 km above the crater and drifted S.
Source: Japan Meteorological Agency (JMA) via the Volcano Research Center
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Small explosive eruptions occurred at Suwanose-jima on 19 August. JMA reported that on the 19th two periods of continuous acoustic signals were recorded for 20-30 minutes each beginning around 0000 and 0630. The signals were the largest recorded thus far this year. Explosions and rumbling were heard from Toshima village, and an ash plume drifted to the SW. Volcanic tremor with continuous large acoustic signals was also recorded later in the day during 0940-0950 and 1410-1500. Small tremor events also occurred, and ash rose above the summit to an unknown height and drifted SE.
Sources: Japan Meteorological Agency (JMA) via the Volcano Research Center; Kyodo News; Associated Press
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Based on information from aircraft reports and JMA, the Tokyo VAAC stated that volcanic ash from Suwanose-jima was reported on 18 June at 1058 at a height of ~6 km drifting E. Ash was not visible on satellite imagery.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
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On 11 October at 1400 an eruption began at Suwanose-jima. Volcanic tremor associated with the eruption was detected during 11 October through at least 15 October. Up to eleven explosions were counted. Acoustic microphones recorded four shock waves associated with large explosions.
Sources: Volcano Research Center-Earthquake Research Institute (University of Tokyo); Japan Meteorological Agency (JMA)
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Volcanic tremor was detected near Suwanose-jima's Otake crater beginning on 25 July at 2200 until at least 26 July. JMA reported that an eruption on 26 July at 1430 produced a volcanic plume that rose to 1.3 km above the crater and drifted to the S. That day seismometers ~2 km SW of the crater recorded explosions at 0501, 0558, 0935, and 1055. According to the Suwanose-jima Branch of the Toshima Village Office, ash fell the morning of 26 July.
Source: Volcano Research Center-Earthquake Research Institute (University of Tokyo)
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Beginning on the morning of 9 May volcanic activity increased at Suwanose-jima when a tremor event commenced. The tremor increased at 1100 and became more violent at 2100. Around noon on 11 May an eruption produced an ash cloud that rose 1-1.5 km above the crater. The Suwanose-jima Branch of Toshima village, ~4 km NNW of the active Otake crater, reported that abundant ash fall was observed in the village on 11 May. Vigorous eruptions on the evening of 12 May and the morning of 13 May deposited up to 3 cm of ash in the village. At 0900 on 14 May the eruption seemed to have stopped. The Sakurajima Volcano Observatory reported that plumes associated with volcanic tremor events have been observed at Suwanose-jima since the new crater was formed during the December 2000 eruption.
Sources: Volcano Research Center-Earthquake Research Institute (University of Tokyo); Tokyo Volcanic Ash Advisory Center (VAAC)
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At ~1700 on 19 December 2000, a Suwanose-jima inhabitant reported "smoke" rising NE of the summit crater. During observations from a helicopter, ash-laden smoke and high-temperature gas emissions were seen emanating from new craters. The Sakura-jima Volcano Research Center observed an increase in volcanic earthquakes deeper than 1 km below the summit in comparison to Fall 1999. They also noted an increase in volcanic earthquakes and tremor shallower than 1 km in comparison to early 2000. Researchers will continue to closely monitor the volcano.
Source: Volcano Research Center-Earthquake Research Institute (University of Tokyo)
Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.
Summit-crater explosions on 28 May
Card 0958 (10 June 1970) Summit-crater explosions on 28 May
"On-take, the summit crater of Suwanose-zima volcano exploded with large explosion sounds at 0000-0050 JST on 28 May 1970. Explosions took place with frequency of about three times a minute. Volcanic smoke at 0730 JST was 2,000-3,000 m high and these activities became quiet at about 0800 JST.
Information Contacts: Y. Sawada, Seismological Division, JMA, Tokyo, Japan.
Explosions on 13 and 20-22 December 1970
Card 1095 (20 January 1971) Explosions on 13 and 20-22 December 1970
The summit crater of On-take peak exploded on the 13th and on the 20th to 22nd of December 1970. During these explosions, volcanic smoke continuously went up about 1,000 m high.
Information Contacts: Y. Sawada, Seismological Division, JMA, Tokyo, Japan.
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Mild Strombolian eruptions continue
Mild Strombolian eruptions continued, with smoke columns reaching heights of 100-1,000 m, rumblings and occasional ash falls.
Information Contacts: Japan Meteorological Agency (JMA), Tokyo.
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Pilots note unusually high "smoke" columns
TOA (domestic) airline pilots noted unusually high "smoke" columns from On-take summit crater in July (table 1). [This crater name, used in original SEAN reports (and Volcanoes of the World), should not be confused with the volcano of the same name on Honshu.]
Table 1. Summary of explosions and other observations from Suwanose-jima, October 1975-December 1985. White vapor was emitted during days not listed in the table for 1977-78. "NVO" for 1979-October 1982 data indicates no visual observation due to bad weather. Numbers in parentheses are the local observation times. Dashes indicate no data provided or unknown. Data have been combined from monthly Bulletin tables and JMA has added data missing from original reports, including May 1984 and 1985. Courtesy of JMA.
| Date | Time Period | Plume Height (m) | Activity |
| 04 Oct 1975 | -- | 700 | Sometimes moderate explosions |
| 05 Oct 1975 | -- | 1000 | Sometimes large explosions, ashfall |
| 06 Oct 1975 | -- | 1500 | Large explosions, ashfall |
| 07 Oct 1975 | -- | -- | Explosion |
| 08 Oct 1975 | -- | 1000 | Large explosion |
| 09 Oct 1975 | -- | 500 | Explosion |
| 09 Nov 1975 | -- | 1500 | Large explosion |
| 10 Nov 1975 | -- | 600 | Explosion |
| 19 Nov 1975 | -- | 500 | Large explosion |
| 07 Dec 1975 | -- | 200 | Sometimes small explosions |
| 21 Dec 1975 | -- | 700 | Frequent large explosions |
| 21 Dec 1975 | -- | 400 | Remarkable incandescent column, frequent large explosions |
| 23 Dec 1975 | -- | 700 | Explosion |
| 24 Dec 1975 | -- | 400 | Sometimes large explosions |
| 25 Dec 1975 | -- | 700 | Explosion |
| 26 Dec 1975 | -- | 1000 | Frequent large explosions |
| 27 Dec 1975 | -- | 700 | Large explosion |
| 28 Dec 1975 | -- | 700 | Moderate explosion |
| 31 Dec 1975 | -- | 400 | -- |
| 08 Jan 1976 | -- | 300 | Large explosion |
| 24 Jan 1976 | -- | 1000 | Ashfall |
| 25 Jan 1976 | -- | 1000 | Large explosion, ashfall |
| 26 Jan 1976 | -- | -- | Ashfall |
| 27 Jan 1976 | -- | 500 | Large explosion, ashfall |
| 28-29 Jan 1976 | -- | 1500 | -- |
| 14 Feb 1976 | -- | -- | Moderate explosion |
| 15 Feb 1976 | -- | 800 | Moderate explosion, ashfall |
| 16 Feb 1976 | -- | -- | Sometimes explosion sounds, ashfall |
| 17 Feb 1976 | -- | -- | Sometimes explosion sounds |
| 18 Feb 1976 | -- | 300 | Sometimes explosion sounds |
| 19 Feb 1976 | -- | 700 | Explosion |
| 20 Feb 1976 | -- | 500 | Moderate explosion |
| 26 Feb 1976 | -- | -- | Explosion |
| 12 Mar 1976 | -- | 500 | Frequent large explosions |
| 13 Mar 1976 | -- | 700 | Frequent large detonations |
| 14 Mar 1976 | -- | 500 | Sometimes moderate explosions |
| 13 Apr 1976 | -- | -- | Moderate detonation |
| 14 Apr 1976 | -- | 300 | Ashfall |
| 15 Apr 1976 | -- | 300 | Ashfall, moderate explosion |
| 16 Apr 1976 | -- | 1000 | Ashfall |
| 10 May 1976 | -- | 500 | Explosion |
| 03 Jul 1976 | -- | 4200 | Moderate detonation |
| 04 Jul 1976 | -- | 3600-4200 | TOA airline pilot observed ashcloud |
| 07 Jul 1976 | -- | 3600 | TOA airline pilot observed ashcloud |
| 23 Jul 1976 | -- | 3000 | Explosion, large ash cloud, ashfall |
| 24 Jul 1976 | -- | 3000 | Explosion, ashfall |
| 04 Oct 1976 | -- | 500 | Ashfall |
| 12 Oct 1976 | -- | 500 | Ashfall |
| 01 Nov 1976 | -- | -- | Ashfall |
| 11 Jan 1977 | -- | 1200 | One explosion |
| 19-21 Mar 1977 | -- | 700 | Ash ejection and ashfall |
| 24-25 Mar 1977 | -- | -- | Two explosions |
| 01-03 Apr 1977 | -- | 1000 | One explosion, ash ejections |
| 10-11 Apr 1977 | -- | 3000 | Ash ejections and ashfall |
| 14-20 Apr 1977 | -- | 1000 | Two explosions, ash ejections and ashfall |
| 27-29 Apr 1977 | -- | 3000 | Explosions, ash ejections |
| 08 May 1977 | -- | -- | One explosion |
| 13-18 May 1977 | -- | 2000 | Several explosions, ashfall |
| 26 May 1977 | -- | 1000 | One explosion |
| 03-05 Jun 1977 | -- | 3000 | Frequent explosions, incandescent column, ashfall |
| 21-22 Jun 1977 | -- | 3000 | Frequent explosions |
| 09-10 Jul 1977 | -- | 4000 | Ash ejections, one explosion |
| 23 Jul 1977 | -- | -- | Explosions |
| 08-10 Aug 1977 | -- | 3000 | Frequent explosions, incandescent ejecta |
| 10-15 Sep 1977 | -- | 3000 | Frequent explosions, ash ejections, ashfall |
| 18 Sep 1977 | -- | 3000 | Ash ejections and ashfall |
| 23 Oct 1977 | -- | 1000 | One ash ejection |
| 26-30 Oct 1977 | -- | 2000 | Ash ejections |
| 14 Nov 1977 | -- | -- | One explosion |
| 19 Nov 1977 | -- | 2000 | Ash ejections |
| 06 Dec 1977 | -- | -- | One explosion |
| 23 Jan 1978 | -- | -- | Three explosions |
| 19 Mar 1978 | -- | 500 | Two ash ejections |
| 22-25 Mar 1978 | -- | 1000 | Ash ejections |
| 09 Apr 1978 | -- | 1000 | Ash ejections |
| 19-22 Apr 1978 | -- | 3000 | Ash ejections and ashfall |
| 01-03 May 1978 | -- | 500 | Ash ejections and ashfall |
| 31 May 1978 | -- | 500 | Frequent explosions, incandescent column |
| 01 Jun 1978 | -- | 500 | Frequent explosions, incandescent column, ashfall |
| 16-19 Jun 1978 | -- | -- | Frequent explosions |
| 02-05 Jul 1978 | -- | 700 | Frequent explosions, incandescent column, ashfall |
| 19-21 Jul 1978 | -- | 3000 | Ash ejections and ashfall |
| 07-10 Aug 1978 | -- | 3000 | Frequent explosions, incandescent column, ashfall |
| 24 Aug 1978 | -- | 2000 | Ash ejections and ashfall |
| 07 Sep 1978 | -- | 3000 | Frequent explosions, ashfall |
| 17 Sep 1978 | -- | -- | One explosion |
| 23-24 Sep 1978 | -- | 700 | Frequent explosions, incandescence |
| 10-12 Oct 1978 | -- | 5000 | Frequent explosions, ashfall |
| 24-28 Oct 1978 | -- | 3000 | Frequent explosions, incandescence, ashfall |
| 06-10 Nov 1978 | -- | 700 | Explosions, incandescence, ashfall |
| 19-22 Nov 1978 | -- | 500 | Explosions, incandescent column, ashfall |
| 04-05 Dec 1978 | -- | 300 | Explosions |
| 06 Feb 1979 | -- | 500 | Explosions, incandescence |
| 14-15 Feb 1979 | -- | 500 | Explosions, ashfall |
| 19 Feb 1979 | -- | 500 | One explosion |
| 22 Feb 1979 | -- | -- | One explosion |
| 11-13 Mar 1979 | -- | 500 | Four explosions |
| 05 Jun 1979 | -- | -- | Incandescent column, explosions |
| 20 Jul 1979 | -- | 500 | Seven explosions, ash emissions |
| 21 Jul 1979 | -- | 200 | Ash emissions |
| 05-06 Sep 1979 | -- | 2000 | Frequent, strong explosions, incandescent columns, ashfall to sea |
| 07 Sep 1979 | -- | 1000 | Ash emissions |
| 08 Sep 1979 | -- | 800 | Ash emissions |
| 09 Sep 1979 | -- | 2000 | Frequent explosions |
| 12 Sep 1979 | -- | 1000 | Ten explosions |
| 10 Dec 1979 | -- | 1500 | Explosions, incandescent blocks, reflected glow |
| 11 Dec 1979 | -- | -- | Ash emissions |
| 12 Dec 1979 | -- | -- | "Flames" in crater |
| 18 Dec 1979 | -- | 300 | Three explosions |
| 05-06 Feb 1980 | -- | 1500 | About 10 explosions, incandescent column |
| 21-22 Mar 1980 | -- | 1000 | Many explosions |
| 25-26 Apr 1980 | -- | 1500 | Explosions: ashfall on inhabited areas |
| 13 May 1980 | -- | -- | Three explosions |
| 18 May 1980 | -- | 500 | Six explosions; persistent ash ejection |
| 04-05 Jun 1980 | -- | 500 | More than 25 explosions |
| 16-19 Jul 1980 | -- | -- | Many explosions |
| 03-08 Aug 1980 | -- | 1500 | Several tens of explosions; incandescent column |
| 21-23 Aug 1980 | -- | 1000 | More than 20 explosions; incandescent column |
| 08-09 Sep 1980 | -- | 1000 | More than 1000 explosions |
| 20 Sep 1980 | -- | -- | Three explosions |
| 24-27 Sep 1980 | -- | 2000 | More than 1000 explosions |
| 25-27 Oct 1980 | -- | 500 | Persistent ash ejection |
| 08-10 Nov 1980 | -- | 1500 | More than 1000 explosions |
| 29 Nov 1980 | -- | 500 | Persistent ash ejection |
| 13 Dec 1980 | -- | -- | Explosions |
| 04-08 Jan 1981 | -- | 100-1000 | Continuous ash cloud |
| 29 Jan 1981 | -- | 500 | Ten explosions |
| 30 Jan 1981 | -- | 300 | Two explosions |
| 31 Jan 1981 | -- | NVO | Two explosions |
| 12 Feb 1981 | -- | 1000 | One explosions |
| 20 Feb 1981 | -- | 1000 | Three explosions |
| 26 Feb 1981 | -- | 500 | 16 explosions |
| 17 Mar 1981 | -- | 1000 | 20 explosions |
| 15 Apr 1981 | -- | NVO | Many explosions |
| 16 Apr 1981 | -- | NVO | 16 explosions |
| 26 Apr 1981 | -- | 500 | Many explosions |
| 14 May 1981 | -- | 500 | Ten explosions |
| 12 Jun 1981 | -- | 1500 | Three explosions |
| 13 Jun 1981 | -- | NVO | Two explosions |
| 15 Jun 1981 | -- | NVO | Three explosions |
| 16 Jun 1981 | -- | NVO | Three explosions |
| 29-30 Jun 1981 | -- | -- | Many explosions |
| 01-04 Jul 1981 | -- | NVO | Many explosions |
| 05 Jul 1981 | -- | 500 | Ten explosions |
| 06 Jul 1981 | -- | NVO | Ten explosions |
| 13 Jul 1981 | -- | NVO | Three explosions |
| 14 Jul 1981 | -- | 2000 | Many explosions |
| 15 Jul 1981 | -- | NVO | Six explosions |
| 26 Nov 1981 | -- | NVO | Many explosions |
| 27 Nov 1981 | -- | 1500 | Many explosions |
| 13 Dec 1981 | -- | 500 | 40-50 explosions; rumbling |
| 14 Dec 1981 | -- | 500 | Many explosions; rumbling |
| 15 Dec 1981 | -- | 500 | 30-40 explosions; rumbling |
| 16 Dec 1981 | -- | 500 | Two explosions |
| 23 Dec 1981 | -- | NVO | Two explosions |
| 02 Jan 1982 | -- | 1500 | Four explosions |
| 23 Jan 1982 | -- | 1000 | 2-3 explosions/hour |
| 25 Jan 1982 | -- | 200 | Ten explosions |
| 26 Jan 1982 | -- | 500 | Many explosions |
| 27 Jan 1982 | -- | 300 | 12 explosions |
| 28 Jan 1982 | -- | 300 | Three explosions |
| 03 Feb 1982 | -- | NVO | Five explosions |
| 06 Feb 1982 | -- | 200 | Five explosions |
| 07 Feb 1982 | -- | 200 | One explosion |
| 08 Feb 1982 | -- | 200 | One explosion |
| 13 Feb 1982 | -- | 1000 | One explosion; rumbling |
| 14-15 Feb 1982 | -- | 500 | Many explosions; rumbling |
| 16-17 Feb 1982 | -- | NVO | Many explosions; rumbling |
| 18 Feb 1982 | -- | 500 | Many explosions; rumbling |
| 19 Feb 1982 | -- | NVO | Six explosions |
| 22 Feb 1982 | -- | 1000 | Three explosions |
| 23 Feb 1982 | -- | NVO | Four explosions |
| 24 Feb 1982 | -- | NVO | Three explosions |
| 25 Feb 1982 | -- | 1000 | Seven explosions; rumbling |
| 26 Feb 1982 | -- | 500 | Five explosions |
| 09 Mar 1982 | -- | 1000 | Many explosions; rumbling |
| 10 Mar 1982 | -- | 1000 | Many explosions; rumbling |
| 11 Mar 1982 | -- | 500 | Ten explosions |
| 28 Mar 1982 | -- | NVO | Ten explosions; rumbling |
| 29 Mar 1982 | -- | NVO | 20-25 explosions; rumbling |
| 30 Mar 1982 | -- | 1000 | Four explosions |
| 31 Mar 1982 | -- | NVO | Six explosions |
| 01 Apr 1982 | -- | 1000 | Two explosions |
| 02 Apr 1982 | -- | 1000 | Ten explosions |
| 03 Apr 1982 | -- | NVO | Three explosions |
| 15 Apr 1982 | -- | 500 | 18-20 explosions; rumbling |
| 17 Apr 1982 | -- | 500 | 5-6 explosions/hour |
| 18 Apr 1982 | -- | NVO | 2-3 explosions/hour |
| 19 Apr 1982 | -- | NVO | Ten explosions; rumbling |
| 05 May 1982 | -- | 200 | One explosion |
| 06 May 1982 | -- | 1000 | Many explosions; rumbling |
| 27 May 1982 | -- | 1000 | One explosion |
| Jun-Jul 1982 | -- | NVO | Quiet |
| 16 Aug 1982 | -- | 1000 | Four explosions |
| 17 Aug 1982 | -- | 500 | Four explosions |
| 02 Sep 1982 | -- | 500 | Five explosions |
| 16 Sep 1982 | -- | NVO | Many explosions |
| 25 Sep 1982 | -- | 200 | Nine explosions |
| 26 Sep 1982 | -- | 200 | Three explosions |
| 05 Oct 1982 | -- | 500 | Three explosions; rumbling |
| 06 Oct 1982 | -- | NVO | Six explosions |
| 07 Oct 1982 | -- | NVO | Seven explosions |
| 08 Oct 1982 | -- | NVO | Ten explosions; rumbling |
| 09 Oct 1982 | -- | 300 | Seven explosions |
| 17 Oct 1982 | -- | NVO | One explosion |
| 03 Nov 1982 | 0500-2200 LT | 500 | 3-4 explosions/hour |
| 04 Nov 1982 | 0500-2200 LT | 500 | 5-6 explosions/hour |
| 05 Nov 1982 | 0700-2100 LT | 500 | 5-6 explosions/hour |
| 06 Nov 1982 | 0500-2200 LT | 500 | 3 explosions/hour |
| 07 Nov 1982 | 0500-2200 LT | 500 | 1-2 explosions/hour |
| 23 Nov 1982 | 0900-1300 LT | 500 | Five explosions |
| 15 Dec 1982 | -- | 500 | Ashfall |
| 17 Dec 1982 | 1300-2000 LT | 1000 | 15-16 explosions |
| 18 Dec 1982 | -- | 500 | Ashfall |
| 19 Dec 1982 | 0900-2100 LT | 1000 | 2-3 explosions/minute |
| 20 Dec 1982 | 0600-2100 LT | 1000 | 1-2 explosions/5 minutes |
| 29 Dec 1982 | 1000-1300 LT | 500 | Two explosions |
| 17 Jan 1983 | 0630-0800 LT | 500 | 4-6 explosions/minute |
| 17 Jan 1983 | 0800-2000 LT | -- | 3-4 explosions/hour |
| 18 Jan 1983 | 0600-2200 LT | Unknown | 3-5 explosions/hour |
| 19 Jan 1983 | 0600-1700 LT | Unknown | 15-20 explosions |
| 28 Jan 1983 | 1700-2200 LT | 500 | 25-30 explosions |
| 29 Jan 1983 | 0500-1800 LT | 700 | 2-3 explosions/minute |
| 29 Jan 1983 | 1800-2200 LT | -- | 4-5 explosions/hour |
| 30 Jan 1983 | 0500-1600 LT | 1000 | 4-5 explosions/hour |
| 10 Feb 1983 | -- | 200 | A few explosions |
| 11 Feb 1983 | 1900-2100 LT | 500 | 1-2 explosions/minute |
| 26 Feb 1983 | 1530-2300 LT | 1000 | 5-6 explosions/minute |
| 27 Feb 1983 | 0500-1200 LT | 1000 | Ten explosions |
| 04 Mar 1983 | -- | Unknown | One explosion |
| 11 Mar 1983 | 1400-2300 LT | 1000 | 2-3 explosions/minute |
| 12 Mar 1983 | 0600-1200 LT | Unknown | 12 explosions |
| 13 Mar 1983 | 0800-1200 LT | -- | Three explosions |
| 28 Apr 1983 | 1400-1600 LT | Unknown | 3-5 explosions/minute |
| 29 Apr 1983 | 1500-1900 LT | 500 | Three explosions |
| 08 May 1983 | 0700-1500 LT | 200 | Six explosions |
| 11 May 1983 | 1400-1500 LT | 200 | Three explosions |
| 12 May 1983 | 1300-1500 LT | 200 | Three explosions |
| 08 Jun 1983 | 1400-1900 LT | 1500 | Seven explosions |
| 09 Jun 1983 | 1500-1800 LT | 1500 | Four explosions |
| 10 Jun 1983 | 0900-2000 LT | 500 | Seven explosions |
| 05-06 Jul 1983 | 2100-0300 LT | -- | Incandescent column |
| 27 Jul 1983 | 1200-1730 LT | 500 | Two explosions |
| 30 Sep 1983 | 0500-0900 LT | 1500 | 7-9 explosions/hour |
| 01 Oct 1983 | 0500-0900 LT | 1000 | 17 explosions |
| 17 Oct 1983 | 0600-1800 LT | Unknown | 15 explosions |
| 18 Oct 1983 | 0530-1130 LT | 1000 | Five explosions |
| 27 Oct 1983 | 1400-2300 LT | 500 | Rumbling |
| 28 Oct 1983 | 0500-1330 LT | 1000 | Rumbling |
| 29 Oct 1983 | 0500- ? LT | 1000 | Rumbling |
| 22 Nov 1983 | 1000-2200 LT | 500 | 10-15 explosions/minute |
| 23 Nov 1983 | 0920-1100 LT | 500 | 15-20 explosions/minute |
| 23 Nov 1983 | 1400-1700 LT | -- | 15-20 explosions/minute |
| 25 Nov 1983 | 0600-1800 LT | 300 | 16 explosions |
| 03 Dec 1983 | 1500-2300 LT | 500 | 2-10 explosions/minute |
| 04 Dec 1983 | 1000-2200 LT | 300 | Six explosions |
| 18 Dec 1983 | 0400-1500 LT | 500 | 2-3 explosions/minute |
| 18 Dec 1983 | 1500-2200 LT | -- | 10 explosions |
| 19 Dec 1983 | 0500-0900 LT | 500 | 15-20 explosions/minute |
| 19 Dec 1983 | 1500-2300 LT | -- | 20 explosions |
| 20 Dec 1983 | 0400-0700 LT | 500 | 2-3 explosions/minute |
| 20 Dec 1983 | 0700-2100 LT | -- | 20 explosions |
| 02 Jan 1984 | 0500-2000 LT | 300 | 13 explosions |
| 26 Jan 1984 | 0600-2200 LT | 300 | 13 explosions |
| 27 Jan 1984 | 500 | 5-7 explosions/hour | |
| 28 Jan 1984 | 0800-2300 LT | 500 | 30-40 explosions/hour |
| 29 Jan 1984 | 0500-1200 LT | 500 | Seven explosions |
| 30 Jan 1984 | 0400-1500 LT | 500 | 10 explosions |
| 14-16 Mar 1984 | -- | -- | 4-5 explosions/minute |
| 18 Mar 1984 | 0500-2300 LT | -- | 10 explosions |
| 12 Apr 1984 | 2100-2300 LT | 1000 | Seven explosions |
| 15 Apr 1984 | 0730-1300 LT | -- | Seven explosions |
| 15 Apr 1984 | 1700-2200 LT | -- | 5-6 explosions |
| 16 Apr 1984 | 0700-1700 LT | -- | Six explosions |
| 17 Apr 1984 | 0500-1000 LT | -- | 12 explosions |
| 18 Apr 1984 | 0600-1000 LT | -- | Three explosions |
| 15 May 1984 | -- | -- | 12-13 explosions |
| 28 Jun 1985 | -- | 2000 | Airplane pilot saw the ash cloud, light ashfall |
| 03 Aug 1985 | -- | -- | Airplane pilot saw the ash cloud |
| 14-15 Sep 1985 | -- | -- | Frequent explosion sounds |
| 01 Oct 1985 | -- | -- | Airplane pilot saw the ash cloud |
| 17-21 Nov 1985 | -- | -- | Frequent explosion sounds |
| 05-06 Dec 1985 | -- | -- | Frequent explosion sounds |
Information Contacts: JMA, Tokyo.
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Frequent explosions and considerable ashfall
Frequent explosions from the summit crater occurred 26-29 April (table 1). Considerable ash fell nearby from eruptive clouds that rose 3,000 m above the vent. Explosion sounds and air shocks were often detected and glow was seen on one or two occasions.
Information Contacts: JMA, Tokyo.
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Explosions continue but are less frequent
Strombolian activity continued into May, but explosions were less frequent.
Information Contacts: JMA, Tokyo; D. Shackelford, CA.
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Eruptions continue; considerable ash deposition
Eruptions from On-take summit crater continued through July, with ash clouds rising 2,000-3,000 m and considerable ash deposition.
Information Contacts: JMA, Tokyo; D. Shackelford, CA.
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Activity continued during August and September
Strombolian activity continued during August and September. An eruption at 1000 on 14 September produced clouds that rose 2,000 m above On-take.
Information Contacts: JMA, Tokyo.
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Activity since January 1977 tabulated
Activity has been observed only once since mid-March (table 1), in contrast to the pattern of the preceding 26 months. From January 1977-March 1979 there were 1-4 periods of tephra ejection per month, each lasting up to a few days.
Information Contacts: JMA, Tokyo.
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Six hours of explosions; air shocks rattle doors and windows 90 km away
"On-take vent exploded on 5 September, after a few small explosions on 20 July (table 1). Explosive activity continued from about 2000 on 5 September to 0100 on 6 September. Incandescent columns rose 500 m above the crater and explosions occurred every 10 seconds during the most active stage on the 5th. Explosive sounds (rumblings) were heard at Yaku-shima Island, 90 km NE of Suwanose-jima, and windows and doors on Yaku-shima were rattled by air vibrations. Ash fell in the sea E of Suwanose-jima.
"A village of 65 people lies on Suwanose-jima Island. People there said that the activity on 5 September was one of the strongest of the many explosive periods since 1956. No damage was caused by the explosions. Explosions at the volcano had become less frequent this year than before."
Information Contacts: JMA, Tokyo.
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Explosions; incandescent tephra; 1979 activity summarized
A loud explosion from On-take summit crater occurred at about 0700 on 10 December, after three months of quiescence. The initial explosion produced a 1.5-km-high cloud, and smaller explosions continued for about 3 hours. Ash clouds then decreased, but ejections of incandescent material and reflected glow were seen that night. Activity decreased further to weak ash emission the next day, although glow in the summit crater were seen from the air on 12 December. The explosions caused no damage on the island.
Information Contacts: JMA, Tokyo.
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Tephra ejection
Aerial observers reported that tephra clouds rose to about 1.8 km above On-take vent on 18-19 May.
Information Contacts: JMA, Tokyo; D. Shackelford, CA.
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December 1979-December 1980 explosions tabulated
Strombolian explosions have occurred almost every month since November 1956 from On-take, the highest point on Suwanose-jima Island. Eruptive activity has typically lasted from one to a few days. The only damage from the 1980 explosions (table 1) was caused by minor ashfalls on crops. Between explosive periods, white vapor rose a few hundred meters above the vent.
Information Contacts: JMA, Tokyo.
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January-August 1981 explosions tabulated
During 1981, explosions from Suwanose-jima have been recorded every month through August. Observations were made from 3 km S of the active B crater (figure 1) and from Nakano-shima Island, 26 km NE. An explosion is registered when visual observation of an eruption cloud is correlated with the sound of an explosion. Aircraft crews reported three eruption clouds: 28 June, cloud height 1.2 km; 17 July, 2.4 km; and 10 August, 2.7 km.
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Figure 1. Topographic map of Suwanose-jima Island; the active vent is in Crater B. Courtesy of JMA. |
Information Contacts: JMA, Tokyo.
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Three days of explosions
After two months of quiesence, Crater B was active 25-28 November. Ash was ejected on 25 November. Explosive sounds were recorded from about 0200 on the 26th. Activity intensified to register 5-6 explosions/minute from 1230 to 1700 that day, then declined to about 10/hour. From 1700 on the 27th to 0200 on the 28th about four explosions/hour were recorded. On 28 November activity was limited to continuous emission of white vapor. The ash and blocks ejected during the activity caused no damage.
Information Contacts: JMA, Tokyo.
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November 1981-October 1982 activity
No damage was reported from 1982 activity, but there was heavy ashfall on the inhabited, S end of the island on 7 October. The eruptive activity typically lasted from one to a few days. Between active periods, white vapor rose a few hundred meters above the vent.
Information Contacts: JMA, Tokyo.
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Summary of activity, November 1982-January 1984
Strombolian activity has been recorded almost every month, November 1982-January 1984 (table 1). No damage was reported, although there were often heavy ashfalls on the inhabited area of the island, along the shore 3.5 km SSW of the active vent.
Information Contacts: JMA, Tokyo.
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Explosions resume; 2.5 km plume; ashfall 25 km SE
Occasional Strombolian activity continued until May 1984, but no explosion sounds had been reported since June (table 1). During the afternoon of 28 June 1985, an aircraft pilot flying near Suwanose-jima saw a plume rising to an altitude of 2-2.5 km (table 1). At Nakano-shima, about 25 km NE of the volcano, slight ashfall was observed, but no explosions were heard.
Information Contacts: JMA, Tokyo.
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Explosions cause 200 m plume
Explosive sounds were heard . . . twice on the morning of 28 July, and a 200-m-high plume was observed from an airplane at around 1200.
Information Contacts: JMA.
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500-600-m-high ash plume
On 2 October, observers aboard a Nihon Kinkyori Airways plane saw the volcano emitting a white plume to ~500-600 m height. An ash plume was sometimes seen from 30 km NE of the summit (in Nakanoshima) by the JMA Mobile Volcanological Observation Team.
Information Contacts: JMA.
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Plume to 1,200-1,500 m
An airplane pilot saw a plume rising to 1,200-1,500 m altitude at 1318 on 11 December.
Information Contacts: JMA.
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Ash eruption
On 24 April, an airplane pilot saw an ash plume rising to 3,000 m altitude.
Information Contacts: JMA.
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Small explosions; light ashfall
Small explosions were heard by residents of the island at a rate of 5-6/day between 0500 and 1500 on 13 April. Ash plumes rose 500-600 m, sometimes accompanied by roaring sounds or air shocks. On 15 April, continued 500-600-m-high ash emission began at 0530. A Japan Air System (formerly TDA airline) pilot saw an ash cloud moving S at 1,800-2,100 m altitude (1,000-1,300 m above the summit) at 0848. A light ashfall was observed at a harbor on the island, but no explosions were heard and no air shocks were felt that day. No explosions were reported the following day.
Information Contacts: JMA.
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3,000-m ash cloud
At 1430 on 18 July, a Southwest Airlines crew observed a 3,000-m-high ash cloud.
Information Contacts: JMA.
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Plume seen from aircraft
A jetliner crew observed a 2.0-km-high plume . . . on 9 August at 1630.
Information Contacts: Y. Sawada, JMA; D. Shackelford, Fullerton, CA.
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Explosions and ashfall; 1988 activity summarized
On 1, 14, and 16 January, residents . . . heard explosions. Ash fell to the S on 21 and 24 January in the the only inhabited part of the small island. On 7 February at 1225, an explosion sound was heard, and on 28 February, a 1,000-m-high ash plume deposited large amounts of ash to the S. At 1640 on 3 March, the crew of a JAS aircraft observed a 2,000-m ash cloud. A summary of [1987-88] explosions and ashfall is shown in table 2.
Table 2. Eruptive episodes at Suwanose-jima, January 1987-October 1988. Courtesy of JMA.
| Date | Time Period | Plume Height (m) | Activity |
| 05 Jan 1988 | -- | -- | Four explosions |
| 16 Jan 1988 | -- | 300 | Five explosions |
| 17 Jan 1988 | -- | 500 | Four explosions |
| 18 Jan 1988 | -- | 300 | One explosion |
| 29 Feb 1988 | -- | -- | Explosion at 1325 caused air shock |
| 08 Mar 1988 | -- | 500 | Eleven explosions accompanied by air shock |
| 28 Mar 1988 | -- | -- | Three explosions accompanied by air shock |
| 13 Apr 1988 | -- | 500 | Five or six explosions per minute |
| 14 Apr 1988 | -- | 500 | 40-50 explosions |
| 15 Apr 1988 | -- | 2000 | TOA Domestic Airlines pilot saw the plume rising 2000 m |
| 16 Apr 1988 | -- | 500 | Ashfall in the S part of the island |
| 18 Jul 1988 | -- | 3000 | Southwest Airlines pilot saw the ash plume rising |
| 09 Aug 1988 | -- | 2000 | Japan Air System pilot saw the plume rising 2000 m |
| 13 Aug 1988 | -- | 500 | Ashfall in the S part of the island |
| 29 Aug 1988 | -- | 300 | Several explosions, ashfall |
| 03 Oct 1988 | -- | 500 | Ashfall in the S part of the island |
| 06 Oct 1988 | -- | -- | Rumbling, ashfall in the S |
| 07 Oct 1988 | -- | -- | Rumbling, ashfall in the S |
Information Contacts: JMA.
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Frequent explosions; ashfall on inhabited area
. . . March-April activity is summarized in table 2. No explosions were observed in May, but several tens of explosions 22-23 June were accompanied by detonations and air shocks. Ash fell on the S part of the small island volcano, in the only inhabited area.
Information Contacts: JMA.
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Vigorous explosions continue
Explosions continued at Suwanose-jima. On 22 and 23 June 1989, several tens of eruptions were reported, accompanied by audible detonations, felt air shocks, and ashfalls on the inhabited S side of the island.
Information Contacts: JMA; D. Shackelford, Fullerton, CA.
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Explosions and ash emissions
Eruptive activity was weak in the first half of 1990, but explosions became frequent in late July, and activity was most vigorous in October and November. The highest ash cloud (1,500 m) was observed, and ash-related agricultural damage was reported, in late October. Glow from the most active crater . . . was seen at night on 27 October and 10-15 November.
Information Contacts: JMA.
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Ash ejection
Late-October explosions from the summit cone of On-take produced ash clouds a few hundred meters high and caused slight ashfalls on the island. The explosions were the most vigorous since similar events in January.
Information Contacts: JMA.
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Tephra clouds from frequent explosions
Island residents reported frequent explosions, ashfalls, and rumbling in early and mid-May. Ash plumes were observed rising to 1.5-2.0 km elevation by Japanese airline pilots on 1-3 May, and a plume was visible on a NOAA weather satellite image at 1538 on 1 May.
Recently, the volcano had been active several times a year, with frequent explosions producing ash clouds and detectable ashfall. During peaks in activity, ash clouds rose to 2-3 km height and tens of small explosions occurred per minute. Eruptive episodes typically lasted for a few days to a month. Explosions had been reported earlier in 1992 on 1-4, 10, and 25-31 January, 4-14 and 21-28 February, 2-4 and 11-12 March, and 15-16 April.
Information Contacts: JMA; W. Gould, NOAA.
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Explosions eject blocks
Island residents reported an increase in activity on the morning of 20 October. Rumbling was heard at 2230 and frequent detonations began the following morning. Numerous blocks were ejected on 22 October with explosive activity decreasing after the 23rd. Explosions in 1992 had been reported 1-3 times a month through May, and on 2 June, 9-10 July, 21-24 September, and 11 October.
Information Contacts: JMA.
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Frequent explosions; lava fountains
Explosive activity . . . ended by 4 November. Additional explosive activity with frequent detonations occurred on 19-22 November. Incandescent lava fountains were observed on the night of 21 November. No damage resulted.
Information Contacts: JMA.
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Sporadic, weak ash eruptions
Sporadic, weak ash eruptions [in March] resulted in slight ashfall on inhabited areas . . . .
Information Contacts: JMA.
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Sporadic, weak ash eruptions
Sporadic, weak ash eruptions continued in April. The island's residents heard explosions [during] 22-26 April.
Information Contacts: JMA.
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Weak ash explosions
Island residents observed weak ash eruptions and heard explosions in late May.
Information Contacts: JMA.
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Eruption produces ashfall up to 100 km away
Eruptive activity in mid-August caused ashfall on this island and on other islands 100 km NE. Pilots from six domestic airlines reported ash clouds up to 3 km above sea level near the volcano on 14-18 August. Seismic monitoring equipment on the island detected no unusual activity.
Information Contacts: JMA.
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Small explosive eruptions
Weak ash eruptions were observed and explosions were heard by island residents through December 1993 following eruptive activity in mid-August . . . .
Information Contacts: JMA.
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Intermittent weak eruptions throughout 1994 cause ashfall on the island
Weak ash eruptions were observed and explosion sounds were heard by local residents throughout 1994. Heavy ash sometimes fell in a village on the island. Occasional ash emissions occurred in mid-February, with ashfall reported on the 11th. Emissions began again in mid-March, with ash falls on the island on 19 and 27 March. The next month, ash eruptions took place on 3-4 and 30 April. Frequent ash ejections during 8-12 May also caused ashfall on the island; detonations were heard on the 8th. Ash ejections were again observed on 14-21 and 29-30 July, with ashfall on the 15th and 20th. Detonations and ashfall were again reported on 12 August. Ashfall was frequent in September and the second half of October, with larger volumes on 13-14 and 31 October. Ash emission in December was observed at the beginning and end of the month, with ashfall on 1-4 and 31 December; rumbling was heard the night of the 3rd.
Information Contacts: JMA; Y. Sawada, JMA; D. Shackleford, Fullerton, CA.
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Continued minor eruptive activity throughout much of 1995
Eruptive activity took place from March to June and from August to December 1995. Some ashfalls were observed at a village 4 km SSW of the crater. The two historically active summit craters and typically have Strombolian eruptions.
Information Contacts: Volcanological Division, Seismological and Volcanological Department, Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100 Japan.
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Small eruptions in January; nine explosions throughout 1995
Monitoring from the Sakurajima Volcanological Observatory revealed nine explosions from Suwanose-jima in 1995. According to the Japan Meteorological Agency and the Kagoshima Prefectural Government, small eruptions during 10-13 January 1996 sent plumes 300-600 m above the volcano and caused ashfall to the S. Activity has been high since 1950, with 1-2 ash emissions every month, and some Strombolian explosions.
Information Contacts: Volcano Research Center, Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html).
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Weak ash eruptions in early March cause ashfalls
Weak ash eruptions were observed on 5 and 6 March; occasional ashfalls were reported on the island. Nine explosions were observed in 1995 and there were small eruptions during 10-13 January (BGVN 21:01). Activity has been high since 1950.
Information Contacts: Volcanological Division, Seismological and Volcanological Department, Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100 Japan.
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Strong eruptions produce volcanic ash clouds
On 2 June, an aviation notice to airmen (NOTAM) indicated a volcanic ash cloud to 4,600 m emanating from Suwanose-jima. A second NOTAM at 1515 on 2 June noted that the ash cloud top was at 2,100 m. No discernible ash plume was evident in GMS satellite data from the Japanese Meteorological Agency (JMA) through 1732 on 2 June.
The Kagoshima Prefectural Government confirmed to JMA that emissions on 1-2 June caused ashfall. Ashfall was also observed on the island on 4 June.
The Sakura-jima Volcanological Observatory of Kyushu University reported that activity has continued at the same level since 1994, with nearly constant A-type earthquakes. Ash emissions have occurred this year on 10-13 January, 23 February, 5-6 March, and 14 April. The eruption column in March rose 500 m above the volcano.
Information Contacts: Volcano Research Center, Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html); Jim Lynch, NOAA/NESDIS Synoptic Analysis Branch (SAB), Room 401, 5200 Auth Road, Camp Springs, MD 20746, USA; Volcanological Division, Japan Meteorological Agency, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan.
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Explosive activity continues
According to Kagoshima Prefectural Government, a weak ash eruption was observed on 14 July. On 22 July a civil aviator reported an ash cloud at ~1.5 km altitude.
Information Contacts: Volcanological Division, Japan Meteorological Agency, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan
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Weak ash emission and rumbling in late December
On 26, 27, and 28 December, the Government of the Kagoshima Prefecture reported weak ash emission and rumbling from Suwanose-jima. A small quantity of ashfall was observed on 27 December.
Information Contacts: Volcanological Division, Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan.
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Ashfall in March and continued ash emissions in April
An ash column 500-600 m high above the summit resulted in ashfall starting at about noon on 24 March and continuing until the evening of the following day. Ash emissions on 16-17 April sent a column 500-700 m high. Seismicity was characterized by numerous B-type earthquakes in March (~50/month), and by volcanic tremors during April (~ 200/month).
Information Contacts: Sakurajima Volcanological Observatory (SVO), Disaster Prevention Research Institute, Kyoto University, Sakurajima-cho, Kagoshima 89114, Japan; Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan.
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Two subsidiary craters discovered; elevated activity in December 2000
An observer on Suwanose-jima reported seeing "smoke" rise from NE of the summit crater at about 1700 on 19 December 2000. The following day, Kazuhiro Ishihara from Sakura-jima Volcano Research Center (SVRC, formerly Sakura-jima Volcano Observatory, SVO) of Kyoto University inspected the crater area during a helicopter flyover. He observed an ash-laden, high-temperature gas emission from the main active crater, On-take, and from two newly formed craters on the outer NE slope of the main crater (figures 2 and 3).
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Figure 2. Topographic map of Suwanose-jima illustrating the main active crater (1), On-take, and the newly discovered craters (2, 3). Thick textured lines are crater rims. Contour interval is 100 m. After a map by SVRC. |
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Figure 3. Photo of the NE slope of Suwanose-jima showing the main active crater (1), On-take, and two subsidiary craters (2, 3). Courtesy of SVRC. |
Subsequent observations on 24 December by Masato Iguchi and Daisuke Miki, both of SVRC, revealed more about the nature of the craters' activities. Craters 2 and 3 were ~40 m and ~200 m away from the main crater rim, respectively. Crater 2 had a diameter of ~25 m, and crater 3 had a diameter of ~10 m. The craters were thermally surveyed from a helicopter. On-take (crater 1) had a temperature of ~450°C, and emitted light-colored vapor. Crater 2 released an ash-laden plume and had a temperature of ~100°C. Crater 3, which had a temperature of ~270°C, ejected gas and a small amount of ash.
Seismicity recorded by SVRC showed that ~10 deep volcanic (A-type) earthquakes occurred monthly, an increase since fall 1999. Shallow volcanic (B-type) earthquakes had also increased since early 2000 with the occurrence of ~50-300 events monthly. Researchers using GPS techniques discovered that deformation had increased the distance between Suwanose-jima and Nakano-shima, a neighboring island, by 1 cm. SVRC indicated that activity was elevated, but that it did not imply an immediate large-scale eruption.
Information Contacts: Disaster Prevention Research Institute, Kyoto University (URL: http://www.dpri.kyoto-u.ac.jp/); Setsuya Nakada and Hidefumi Watanabe, Volcano Research Center, Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html).
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Explosive eruptions in May and July
Several eruptions occurred at Suwanose-jima in May-July 2001. Beginning on the morning of 9 May 2001 volcanic activity increased at Suwanose-jima when a tremor event commenced (figure 4). The tremor increased at 1100 and became more violent at 2100.
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Figure 4. Daily eruptions, tremor events, and B and A earthquakes registered at Suwanose-jima up to 11 May. Here, an eruption is defined as a volcanic earthquake, associated with an acoustic signal of more than 1 Pa. Courtesy of the Japanese Meteorological Agency. |
On 11 May an eruption produced ash clouds that rose to 1.8-7.6 km altitude. A seismo-acoustical record of an eruption signal on 10 May is shown on figure 5. Abundant ash fell on 11 May [in the village ~4 km SSW of the active crater].
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Figure 5. Seismo-acoustical record of an eruption signal received at Suwanose-jima on 10 May. The bottom panel shows the requisite acoustic signal that was recorded by a microphone. Courtesy of the Japanese Meteorological Agency. |
Vigorous eruptions on the evening of 12 May and the morning of 13 May deposited up to 3 cm of ash in the village (figure 6). At 0900 on 14 May the eruption seemed to have stopped.
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Figure 6. Photo taken from a helicopter of the beginning of the 12 May eruption at Suwanose-jima. Courtesy of the Japanese Meteorological Agency. |
The Sakurajima Volcano Observatory also reported that plumes associated with volcanic tremor events have been observed at Suwanose-jima since the new crater was formed during the December 2000 eruption.
Volcanic tremor was also detected near Suwanose-jima's On-take (Otake) crater beginning at 2200 on 25 July and lasting until at least 26 July. JMA reported that an eruption on 26 July at 1430 produced a volcanic plume that rose to 1.3 km above the crater and drifted to the S. That day seismometers ~2 km SW of the crater recorded explosions at 0501, 0558, 0935, and 1055. Ash fell [in the village] the morning of 26 July.
Information Contacts: Japanese Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100 Japan; Tokyo Volcanic Ash Advisory Center, Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/); Disaster Prevention Research Institute, Kyoto University, Japan (URL: http://www.dpri.kyoto-u.ac.jp/); Setsuya Nakada and Hidefumi Watanabe, Volcano Research Center, Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html).
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Volcanic tremor, plumes, and ash eruptions during October 2001-August 2002
The Japanese Meteorological Agency (JMA) reported that, following the latest eruptive activity that had ended on 30 July, an eruption began around 1400 on 11 October 2001 at Otake Crater. Volcanic tremor had started around 1200 on 11 October and continued through 15 October. Up to 11 explosions occurred. An acoustic microphone installed on the island recorded four shock waves associated with larger explosions.
On 18 June 2002 during 1130-1300 a plume was observed (figure 7), and on the morning of 19 August 2002, JMA issued a volcanic advisory for Suwanose-jima. Volcanic tremor events associated with continuous acoustic signals (the largest so far in 2002) occurred for 20- to 30-minute periods around 0000 and 0630, and also during 0940-0950, 1410-1500, 1810-1815, and 1920-1930. Small tremor events also occurred. Witnesses in [the village 4 km SSW of the crater] heard continuous rumblings and explosion sounds every 2-3 seconds. The summit was covered with clouds and abundant ash drifted SW and SE. The summit crater emitted steam to an unknown height. A large plume was seen on satellite imagery on 19 August (figure 8). Eruption clouds were visible on 10, 16, and 20 August 2002 (figure 9).
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Figure 7. Satellite image of the plume from Suwanose-Jima volcano observed at 1132 (local time) on 18 June 2002. The plume was visible from 1130-1300. Courtesy Charles Holliday, AFWA. |
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Figure 8. Satellite view showing plume emitted from Suwanose-jima on 19 August 2002 at 1808 (local time). Courtesy Charles Holliday, AFWA. |
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Figure 9. Eruption clouds emitted from Suwanose-jima at 1640 on 10 August 2002. The clouds were observed through live camera images provided by the Satellite Image Network Group (SiNG). Courtesy N. Uchida, JMA. |
On 21 and 22 August JMA reported that eruptive activity continued but at a lower level. On 20 August, volcanic tremor events occurred during 0115-0120 and 0625-0655. Witnesses in [the] village reported that the rumbling noises became weaker, though they were sometimes accompanied by large explosion sounds. Ashfall occurred in Naze city on Amami-oshima island (~140 km S) during the afternoon. Faint ashfall was observed ~4 km SSW of the summit on 20 and 21 August.
Observations from the air on 21 August revealed the December 2000 crater (BGVN 26:02) generating an ash cloud to 1.5 km above the crater that was drifting S.
Information Contacts: N. Uchida, Japanese Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan; Volcano Research Center (VRC), Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html); Charles Holliday, Air Force Weather Agency (AFWA), Satellite Applications Branch, Offutt AFB, NE 68113-4039; Satellite Image Network Group (SiNG), Faculty of Education, Kagoshima University, Kagoshima 890, Japan.
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Ash explosions in September and December 2002, and activity in January 2003
Though the volcano had been relatively quiet since 26 August 2002 (BGVN 27:07), the Japan Meteorological Agency reported that explosive eruptions became frequent on the morning of 12 September 2002. Rumbling was heard intermittently at a location ~4 km SSW of the summit, and light ashfall was observed on 12 September. Explosions occurred at 0816, 1246, 1746, and 1754 on 12 September, and at 0853, 1016, and 1027 on 13 September.
A pilot report contained in the Kagoshima Airport weather observation issued at 1000 on 5 December 2002 noted a plume estimated to be between 900 and 1,200 m altitude. The U.S. Air Force Weather Agency noted that the plume was also seen on DMSP (Defense Meteorological Satellite Program) imagery at 1034 and on NASA Terra MODIS imagery at 1055 on 5 December.
The REAL-Volc Project at the Volcano Research Center, Earthquake Research Institute, University of Tokyo, has detected several thermal anomalies on Suwanose-jima since they started an AVHRR monitoring system in 2001. Anomalies were seen on 11 October 2001, 20 November 2001, 30 December 2001, 20 April 2002, and 12 January 2003.
Information Contacts: Naokuni Uchida, Japan Meteorological Agency (JMA-Fukuoka Center), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan (URL: http://www.jma.go.jp/); Takayuki Kaneko, Volcano Research Center, Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html); Charles Holliday, U.S. Air Force Weather Agency, 106 Peacekeeper Drive, Ste 2NE, Offut AFB, NE 68113-4039, USA (URL: http://www.557weatherwing.af.mil/).
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Sporadic eruptions in 2003 and in January 2004, one to 2.4 km altitude
Suwanose-jima volcano was last reported in BGVN 28:04, when activity was noted in September and December 2002, with thermal anomalies continuing into January 2003. HIGP MODIS thermal imagery revealed only one alert in the year to 13 April 2004, that being on 4 July 2003. NASA Terra and Defense Meteorological Satellite Program imagery dated 7-8 November 2003 showed an ash plume rising from Suwanose-jima to an estimated height of 2,400 m (figure 10) on those days.
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Figure 10. Ash plume from Suwanose-jima on 8 November 2003 imaged by the MODIS instrument on the NASA AQUA satellite. Courtesy Defense Meteorological Satellite Program (DMSP) and Charles Holliday. |
According to Tokyo VAAC reports, using information from the Japanese Meteorological Agency, explosions also took place at Suwanose-jima on 15 December 2003 at 1946, and 21 December at 1828, each of which produced plumes to an unknown height. The VAAC reported several small emissions on 27 and 28 December, again rising to unknown heights and an eruption on 28 December at 0820 rising to ~ 1.5 km altitude and extending E. On 2, 4 and 21-22 January 2004 small explosions produced ash plumes to unknown heights.
Information Contacts: Japan Meteorological Agency (JMA), Volcanological Division 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan (URL: http://www.jma.go.jp/); HIGP MODIS Thermal Alert System, Hawaii Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa (URL: http://modis.higp.hawaii.edu/); Charles Holliday, Air Force Weather Agency (AFWA), Satellite Applications Branch, Offutt AFB, NE 68113-4039, USA.
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Eruptions during April 2004-July 2005 send plumes to varying heights
Several small eruptions during December 2003 and January 2004 at Suwanose-jima produced ash plumes to unknown heights (BGVN 29:03). Little activity was observed during the first four months of 2004. From the end of April 2004 to the end of July 2005, numerous eruptions and explosions produced plumes reported by the Tokyo Volcanic Ash Advisory Center (VAAC), including some observed by pilots (table 3).
Table 3. Summary of activity at Suwanose-jima from April 2004 to July 2005 based on information from the Tokyo VAAC. "--" indicates data not reported or unknown.
| Date | Time Period | Plume Altitude (km) | Drift Direction | Activity |
| 28 Apr 2004 | -- | 3 | SE | Ash emission |
| 01 May 2004 | 0906 | -- | -- | Explosion |
| 07 Jun 2004 | -- | 2 | E | Gas plume |
| 08 Jun 2004 | -- | 2 | E | Gas and ash |
| 09 Jun 2004 | 1003 | 1.8 | E | Ash plume |
| 09 Jun 2004 | 1300 | -- | -- | Ash plume |
| 30 Jun-05 Jul 2004 | various | max 1.9 | -- | Several explosions |
| 30 Nov 2004 | 1607 | 1.2 | -- | Eruption |
| 20 Dec 2004 | -- | 1.8 | SE | Eruption |
| 21 Dec 2004 | -- | -- | SE | Eruption |
| 22 Dec 2004 | -- | -- | -- | Ash plume |
| 24 Dec 2004 | -- | -- | -- | Ash plume |
| 25 Dec 2004 | -- | -- | -- | Ash plume |
| 27 Dec 2004 | -- | -- | -- | Ash plume |
| 29 Dec 2004 | -- | 1.2 | -- | Ash plume |
| 01 Jan 2005 | -- | -- | -- | Eruption |
| 04 Jan 2005 | -- | -- | -- | Eruption |
| 06 Mar 2005 | -- | 1.5 | -- | Ash emission |
| 08 Mar 2005 | -- | 1.2 | -- | Ash emission |
| 09 Mar 2005 | -- | 1.8 | -- | Ash plume |
| 26 Apr 2005 | -- | 1.2 | E | Eruption |
| 26 May-31 May 2005 | various | max 2.1 | -- | Several ash explosions |
| 01 Jun-06 Jun 2005 | various | Several ash explosions | 1.8 | -- |
| 06 Jul 2005 | various | -- | -- | Several ash explosions |
| 27 Jul 2005 | -- | 0.8 | -- | Eruption with ash |
| 28 Jul 2005 | -- | 2.4 | -- | Ash plume |
Information Contacts: Tokyo Volcanic Ash Advisory Center, Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan (URL: https://ds.data.jma.go.jp/svd/vaac/data/).
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Eruptions of July 2005-December 2007 send plumes to varying heights
Suwanose-jima, in the East China sea, is one of Japan's most active volcanoes. Our last report on Suwanose-jima (BGVN 30:07) tabulated the seismicity and the numerous ash plumes seen between April 2004 and July 2005. The current report continues the tabulation from August 2005 to December 2007 (table 4).
Table 4. Summary of activity reported at Suwanose-jima from August 2005 to December 2007, based on information from the Tokyo VAAC. "--" indicates that data were not reported.
| Date | Activity | Plume Altitude (km) | Drift Direction |
| 11 Aug-12 Aug 2005 | Small eruptions | ~ 3.4 | -- |
| 22 Sep 2005 | Plume | ~ 1.8 | W |
| 07 Oct-09 Oct 2005 | Eruptions | max. 1.8 | SW, E, SE |
| 01 Jan 2006 | Explosions | -- | -- |
| 10 Jan 2006 | Explosions | ~ 1.8 | E |
| 24 Jan 2006 | Plume | 1.5 | E |
| 28 Jan 2006 | Plume | max. 1.8 | W |
| 29 Jan 2006 | Explosion | -- | -- |
| 31 Jan 2006 | Plume | 1.5 | W |
| 01 Feb 2006 | Explosions | -- | -- |
| 06 Feb-07 Feb 2006 | Explosions | 1.2 | NW |
| 08 Feb-10 Feb 2006 | Plumes | max. 1.5 | E and SE |
| 15 Feb-18 Feb 2006 | Plumes | max. 1.5 | E and S |
| 22 Feb-24 Feb 2006 | Eruptions | max. ~ 3 | S, E, NE |
| 02 Mar-08 Mar 2006 | Explosions | max. ~ 1.8 | E, SE, S, NW |
| 16 Apr 2006 | Ash plume | ~ 1.5 | -- |
| 07 Jun 2006 | Ash plume | 2.4 | -- |
| 30 Jun 2006 | Plume | 1.2 | NE |
| 16 Jul 2006 | Ash plume | 1.8 | N |
| 26 Jul-30 Jul 2006 | Explosions | max. ~ 1.8 | N, straight up |
| 11 Aug-14 Aug 2006 | Explosions | max. ~ 1.8 | N and W |
| 26 Aug 2006 | Plumes | 1.8 | Straight up |
| 28 Aug 2006 | Plumes | 1.5 | E |
| 19 Sep 2006 | Ash plumes | 3.4 | E |
| 20 Sep 2006 | Ash and steam | 2.1 | N |
| 06 Oct 2006 | Explosion | -- | -- |
| 14, 16-17 Oct 2006 | Ash plumes | 3 | -- |
| 18 Oct 2006 | Explosion | -- | -- |
| 27 Oct-28 Oct 2006 | Ash plumes | 1.8 | E |
| 04 Nov-06 Nov 2006 | Plumes | 1.2 | E and SW |
| 09 Nov 2006 | Plume | 1.5 | W |
| 17 Nov 2006 | Plume | 2.1 | Straight up |
| 19 Dec 2006 | Eruption | -- | -- |
| 09 Jan 2007 | Plume | -- | -- |
| 28 Jan 2007 | Plume | -- | -- |
| 05 Feb-07 Feb 2007 | Plume | -- | -- |
| 19 Feb-20 Feb 2007 | Plumes | -- | -- |
| 02 Mar 2007 | Plume | 1.2 | W |
| 17 Mar 2007 | Explosion | -- | -- |
| 30 Mar 2007 | Explosion | -- | -- |
| 02 Apr 2007 | Explosion | -- | -- |
| 08 May 2007 | Explosions | -- | -- |
| 26 Jul 2007 | Ash plume | 1.5 | SW |
| 17 Sep 2007 | Explosions | -- | -- |
| 16 Oct 2007 | Plume | 1.5 | E |
| 22 Oct 2007 | Plume | 1.5 | W |
| 26 Oct-28 Oct 2007 | Plumes | 1.5 | E and W |
| 29 Nov-02 Dec 2007 | Plumes | 1.2-1.8 | E |
| 10 Dec 2007 | Plumes | 1.5-1.8 | W |
| 14 Dec-17 Dec 2007 | Plumes | 1.5-1.8 | E |
During the reporting interval, the Tokyo Volcanic Ash Advisory Center reported small explosions or eruptions, usually accompanied by ash plumes, every month during this period, except for November and December 2005, May 2006, and June 2007. Ash was seldom identified on satellite imagery. On 20 September 2006, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite detected ash-and-steam emissions (figure 11).
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Figure 11. Ash plume blowing N from Suwanose-jima on 20 September 2006, seen in a MODIS image. In color images the plume's hue clearly distinguishes it from the banks of transversely oriented white weather clouds. NASA image created by Jesse Allen, Earth Observatory, using data provided courtesy of the MODIS Rapid Response team. |
Information Contacts: Tokyo Volcanic Ash Advisory Center (Tokyo VAAC), Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan (URL: https://ds.data.jma.go.jp/svd/vaac/data/); NASA Moderate Resolution Imaging Spectroradiometer (MODIS) program (URL: http://modis.gsfc.nasa.gov/).
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Small (~1 km) plumes noted during late 2007-early 2008
Our last Bulletin (BGVN 3211) covered eruptive activity during July 2005 to December 2007. This issue covers eruptions recorded by the Tokyo Volcanic Ash Advisory Center (VAAC) from December 2007 to March 2008. Kinoshita and others (2003) noted that Sakura-jima "has been the most eruptive in Japan, with the eruption columns a few kilometers above the crater occasionally."
Table 5 summarizes information gathered by the Tokyo VAAC from observers between 9 December 2007 and 21 March 2008. In all cases the VAAC could not detect plumes using satellite data. An overview of satellite and image monitoring of Suwanose-jima appears in an article by Kinoshita and others (2003).
Table 5. A summary of Tokyo VAAC reports on ash plumes from Suwanose-jima during 9 December 2007 to 21 March 2008. Cases with only dashes in the data fields were when observers detected an explosion but they were unable to say more about a resulting plume. In many of the examples given, there were multiple Volcanic Ash Advisories issued, but no new data came to light. Courtesy of the Tokyo VAAC.
| Date | Time (UTC) | Plume Altitude (km) | Drift Direction |
| 09 Dec 2007 | 2340 | 1.5 | W |
| 10 Dec 2007 | 0734 | 1.8 | W |
| 14 Dec 2007 | 0914 | -- | -- |
| 15 Dec 2007 | 0016 | 1.8 | E |
| 16 Dec 2007 | 0353 | 1.5 | E |
| 16 Dec 2007 | 2310 | 1.5 | E |
| 08 Feb 2008 | 0248 | 1.8 | E |
| 13 Feb 2008 | 0208 | -- | -- |
| 21 Mar 2008 | 1622 | -- | -- |
Reference. Kinoshita, K., Kanagaki, C., Minaka, A., Tsuchida, S., Matsui, T., Tupper, A., Yakiwara, H., and Iino, N., 2003, Ground and Satellite Monitoring of Volcanic Aerosols in Visible and Infrared Bands: The CEReS International Symposium on Remote Sensing - Monitoring of Environmental Change in Asia, Chiba, Japan, 16-17 December 2003, 10 p.
Information Contacts: Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: https://ds.data.jma.go.jp/svd/vaac/data/).
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Eruption continues from 2007 into 2008
Historically, Suwanose-jima (figure 12) has been one of Japan's most frequently active volcanoes. Our last report on Suwanose-jima, (BGVN 33:02) listed ash plumes between 9 December 2007 and 21 March 2008. This report continues the list through 26 October 2008.
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Figure 12. Simplified map of the geology of Suwanose-jima. The active crater, O-take (Oc), appears at the southern end of the small, sparsely populated island. Courtesy of Taketo Shimano. |
According to a 2008 International Civil Aviation Organization (ICAO) report, the Tokyo VAAC issued 70 volcanic ash advisories for Suwanose-jima during the 17-month period of January 2007-May 2008. This included seven from January through May 2008 (ICAO, 2008). Table 6 summarizes reports of explosive events and plumes for January-October 2008.
Table 6. A summary of Tokyo VAAC reports on explosive events and resulting ash plumes from Suwanose-jima from April through October 2008 (continued from table in BGVN 33:02). For some events, observers detected an explosion but were unable to observe a resulting plume. Courtesy of Tokyo VAAC, based on information from the Japanese Meteorological Agency (JMA) or pilot reports.
| Date | Plume Altitude (km) | Drift Direction |
| 16 Apr 2008 | -- | -- |
| 16 Jun 2008 | -- | -- |
| 29 Jul 2008 | 0.6 | S |
| 07 Aug 2008 | 1.2 | -- |
| 24-26 Aug 2008 | 1.8-2.4 | -- |
| 04-06 Sep 2008 | 1.5-1.8 | E (5 Sep) |
| 24-29 Sep 2008 | 1.5-3 | NE, E, and SW |
| 01-02 Oct 2008 | -- | -- |
| 07-10 Oct 2008 | 2.1 | -- |
| 16, 18-20 Oct 2008 | 1.2-2.5 | W |
| 21, 23, 25-26 Oct 2008 | 1.5-3.0 | W and E |
MODIS/MODVOLC thermal alerts were measured by satellite-borne radiospectroradiometer during 2008 through 6 November (table 7). The island is often covered by clouds, preventing consistent detections.
Table 7. Thermal anomalies measured by MODIS satellite analyzed by the MODVOLC algorithm for Suwanose-jima volcano in 2008 through 6 November. Courtesy of Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System.
| Date | Time (UTC) | Pixels | Satellite |
| 30 Jul 2008 | 1710 | 1 | Aqua |
| 31 Jul 2008 | 1335 | 1 | Terra |
| 22 Sep 2008 | 1350 | 1 | Terra |
NASA satellite observation of 19 October 2008. According to the NASA MODIS Rapid Response team and the NASA Earth Observatory, the volcano released a continuous plume of ash and steam in late October 2008. They noted that a Moderate Resolution Imaging Spectroradiometer (MODIS) captured an image of an ash plume on 19 October 2008. In this image, the plume formed a rippling pattern as it blew WSW. The plume differed from the nearby clouds in both its slightly darker color and more diffuse shape. Near the summit, the plume appeared beige.
References. International Civil Aviation Organization (ICAO), 2008, Fourth Meeting of the International Airways Volcano Watch Operations Group (IAVWOPSG), Paris, France, 15-19 September 2008: Working Paper 34, VAAC Tokyo Management Report, 6 p. (URL: http://www.icao.int/anb/iavwopsg/meetings/iavwopsg4/wp).
Information Contacts: Taketo Shimano, College of Environment and Disaster Research, Fuji-Tokoha University, 325 Obuchi, Fuji-shi, Sizuoka 417-0801, Japan (URL: http://www.eri.u-tokyo.ac.jp/shimano/); International Airway Volcanic Watch Operations Group of the International Civil Aviation Organization (URL: http://www.icao.int/anb/iavwopsg); Tokyo Volcanic Ash Advisory Center (VAAC) (URL: http://ds.data.jma.go.jp/svd/vaac/data/); NASA MODIS Rapid Response team, NASA Goddard Space Flight Center NASA; NASA Earth Observatory (URL: http://earthobservatory.nasa.gov/NaturalHazards); Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).
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Explosive eruptions continue through 6 July 2009
This small uninhabited island, one of Japan's most active volcanoes, lies ~ 175 km SSW of Kyushu Island. Previous reports on Suwanose-jima (BGVN 30:07, 32:11, 33:02, and 33:09) listed ash plumes between 28 April 2004 and 26 October 2008. This report continues the compilation through 6 July 2009 (table 8). Ash plumes were consistent and minor, below ~ 2.5 km altitude.
Table 8. A summary of Tokyo Volcanic Ash Advisory Center (VAAC) reports on explosive events and ash plumes from Suwanose-jima, 29 October 2008 to 6 July 2009. For some events, observers detected an explosion but were unable to observe a plume (indicated by --). Courtesy of Tokyo VAAC, based on information from the Japanese Meteorological Agency (JMA), pilot reports, and satellite imagery.
| Date (UTC) | Plume Altitude (km) | Drift Direction |
| 29-30 Oct 2008 | 1.5-1.8 | E |
| 31 Oct-01 Nov 2008 | -- | -- |
| 03 Nov 2008 | 1.5-1.8 | E |
| 05 Nov 2008 | 1.5 | NE |
| 07 Nov-08 Nov 2008 | 1.2-1.8 | E |
| 12 Nov-16 Nov 2008 | -- | -- |
| 13 Nov-15 Nov 2008 | 1.5-2.1 | -- |
| 21 Nov 2008 | 1.5 | E |
| 25 Nov 2008 | -- | -- |
| 10 Dec-12 Dec 2008 | 0.9-1.8 | E |
| 14 Dec-17 Dec 2008 | 0.9-1.8 | E |
| 19 Dec-20 Dec 2008 | 1.5 | E (17, 19 Dec) |
| 26 Dec-28 Dec 2008 | 1.5-1.8 | -- |
| 30 Dec 2008 | -- | -- |
| 03 Jan 2009 | 1.2 | E |
| 09 Jan 2009 | -- | -- |
| 21 Jan 2009 | -- | -- |
| 18 Feb 2009 | 0.4 | -- |
| 19 Feb-21 Feb 2009 | -- | -- |
| 26 Feb-02 Mar 2009 | 1.2-1.5 | E (1 Mar) |
| 03 Mar 2009 | -- | -- |
| 06 Mar 2009 | -- | -- |
| 15 Mar-16 Mar 2009 | 1.5 | E (15 Mar) |
| 28, 30 Mar 2009 | -- | -- |
| 06, 8, 10 Apr 2009 | -- | -- |
| 21 Apr 2009 | -- | -- |
| 22 Apr-23 Apr 2009 | 1.2-1.5 | E, S |
| 27 Apr 2009 | -- | -- |
| 28 Apr-01 May 2009 | 1.5-1.8 | E, W |
| 07-09, 12-13 May 2009 | -- | -- |
| 17 May 2009 | 2.1 | -- |
| 25 May 2009 | 1.5 | -- |
| 16 Jun 2009 | -- | -- |
| 06 Jul 2009 | -- | -- |
Yukio Hayakawa passed along quantitative data on the explosive eruption on 18 February 2009. The maximum amplitude of ground velocity computed from the analog data was expressed in units of 10-5 m/s (in Japan this unit is expressed as mkine). The values on the 18th were 5.38 x 10-5 m/s; and the airwave was 11 Pa. Hayakawa also indicated that the two explosive eruptions on 20 February had maximum amplitudes of 4.31 x 10-5 m/s and 5.76 x 10-5 m/s, respectively. The airwaves recorded were 20 and 18 Pa, respectively at microphones.
A visible-wavelength image from MODIS captured a small Suwanose-jima plume on 5 July 2009 (figure 13). As of mid-2009, no thermal alerts had been recorded by MODVOLC since 22 September 2008. The island is often covered by clouds, thwarting detection.
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Figure 13. Image of Suwanose-jima taken on 5 July 2009 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite. A beige-colored plume fans out and remains conspicuous for ~ 18 km to the NE blowing toward the island of Yaku-shima. Courtesy of NASA Earth Observatory and the US Air Force Weather Agency. |
Information Contacts: Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/); Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/); U.S. Air Force Weather Agency (AFWA)/XOGM, Offutt Air Force Base, NE 68113, USA; Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Yukio Hayakawa, Gunma University, Faculty of Education, Aramaki 4-2, Maebashi 371-8510, Japan.
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Many small explosions up to 2 km altitude during mid-2009 to mid-2011
In a previous report (BGVN 34:07) we discussed ash plume data from the Tokyo Volcanic Ash Advisory Center (VAAC) and reports from the Japan Meteorological Agency (JMA) that covered explosive activity based on infrasound measurements and seismicity during October 2008 to July 2009. Many explosions were heard and felt but cloud cover obscured direct observations. From 6 July 2009 to 14 July 2011 the Tokyo VAAC reported 234 explosions; 62 of which produced a measurable ash plume (table 9) from the summit crater, On-take (also called Otake).
Table 9. A summary of Tokyo Volcanic Ash Advisory Center (VAAC) reports on measured ash plumes from Suwanose-jima, 15 July 2009 to 14 July 2011. Courtesy of Tokyo VAAC, based on information from the JMA, pilot reports, and satellite imagery.
| Date (UTC) | Plume Altitude (km) | Drift Direction |
| 15-17 Jul 2009 | 1.5-2.1 | NE, W |
| 16-17 Aug 2009 | 1.8 | E |
| 28-29 Aug 2009 | 1.5-2.4 | W |
| 17-18 Sep 2009 | 1.5 | S |
| 01 Oct 2009 | 1.5 | W |
| 10 Oct 2009 | 1.5 | -- |
| 04-05 Nov 2009 | 1.2-1.8 | SW, W, NE |
| 26 Nov 2009 | 3.0 | E |
| 14 Dec 2009 | 1.2-1.5 | E |
| 22 Dec 2009 | 1.5 | -- |
| 02 Jan 2010 | 1.8 | -- |
| 04-05 Jan 2010 | 1.5-1.8 | NE, E |
| 09 Jan 2010 | 1.8 | E |
| 26-27 Jan 2010 | 1.2-1.5 | SE, W |
| 29 Jan 2010 | 1.8 | -- |
| 17 Feb 2010 | 1.2-1.5 | E, SE |
| 19 Feb 2010 | 1.5 | SE |
| 21 Feb 2010 | 1.8 | -- |
| 15-16 May 2010 | 1.5-1.8 | NW |
| 23 Jul 2010 | 2.4 | NW |
| 26 Jul 2010 | 1.5 | W |
| 22 Sep 2010 | 1.5-2.1 | SE |
| 25 Sep 2010 | 1.5 | E |
| 05 Oct 2010 | 1.5 | E |
| 17 Oct 2010 | 1.5 | SE |
| 10-12 Nov 2010 | 1.5-2.1 | SE, N, SW |
| 18 Nov 2010 | 1.8 | -- |
| 21 Nov 2010 | 2.1 | NE |
| 29 Nov 2010 | 1.2-1.5 | -- |
| 04 Dec 2010 | 1.2 | SE |
| 13 Jan 2011 | 1.2 | SE |
| 22 Jan 2011 | 1.5 | S |
| 05 Feb 2011 | 0.6 | SW |
| 12 Apr 2011 | 1.8 | -- |
| 14 Jul 2011 | 3.7 | -- |
JMA stated that this volcano has erupted every year since 1956. The activity alert status for Suwanose-jima was Level 2 (on a 1 to 5 scale where 5 is the highest) from December 2007 to July 2011; this status indicates that the crater is too dangerous to visit.
Activity during late 2009. The Tokyo VAAC reported frequent plumes from mid-August through December 2009. The tallest plumes, above 1.5 km altitude, occurred on 16-17 and 29 August, and 5 and 26 November (table 9). According to JMA, a visitor during 29-30 December 2009 saw Strombolian eruptions.
Activity during 2010. Ash plumes up to ~ 2.4 km altitude were reported by the Tokyo VAAC on many days throughout the year (table 9).
Based on the seismic record, JMA was able to infer when explosions occurred within the crater. The number of these explosions decreased from 64 in January to 0 in June; from July to September there were less than 20 monthly explosions, but activity appeared to peak in November when 94 explosions were recorded.
Aerial observations were made in collaboration with the Japan Maritime Self Defense Force (JMSDF) on 14 December (figure 14). The flight confirmed high temperature areas at both the summit crater's center and at the lower, outer rim. Thes results were congruent with those obtained earlier, in December 2009, and JMA concluded that similar conditions prevailed in the crater during this interval.
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Figure 14. Thermal imaging of Suwanose-jima's summit crater, On-take, taken on 14 December 2010. On the false-color scale (calibrated at right), the highest temperatures are white, the lowest temperatures are blue, showing values in Celsius. The maximum temperature from photo B is 442.5°C; maximum temperature from photo D is 106.1°C. Courtesy of JMA; photos by the Japan Maritime Self Defense Force (JMSDF), Kanoya Air Base. |
Activity during 2011. Ash plumes were reported by the Tokyo VAAC for January, February, April, and July; the tallest occurred on July 14 and reached ~ 3.6 km altitude (table 9). From January to July 2011, volcanic earthquakes and tremor remained relatively high (figure 15).
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Figure 15. Geophysical data recorded for Suwanose-jima from 2003 to July 2011. The uppermost plot indicates eruptions (red arrows, at top) and the daily maximum plume height in meters (histogram). High-frequency (A-type) earthquakes are separated from low-frequency (B-type) earthquakes. JMA also reported monthly tremor durations (not shown here). Courtesy of JMA. |
A 2.9-magnitude earthquake centered below Suwanose-jima occurred on 3 February 2011 at 2206. That month, local inhabitants reportedly felt 17 earthquakes. No surface change was observed before or after the earthquakes. Surveillance in February 2011 included visual observations by the Coast Guard.
Immediately after the 11 March 2011 Tohoku Earthquake (M 9.0, located offshore of Honshu, Japan) instruments at Suwanose-jima recorded increases in high-frequency (A-type) earthquakes. A-type earthquakes are generally considered to have shallow focal depths; B-type earthquakes, deeper focal depths.
Ash explosions seemingly rarely occurred through March 2011, but reports from [the village 4 km SSW of the crater] stated that observers there had seen ballistics thrown from the summit crater. Due to prolonged poor weather, surveillance cameras did not record this activity. JMA reported that plume heights for April, May, and June 2011 remained at background levels, with maximum heights of 0.4?1.0 km. Intermittent incandescence was recorded with surveillance cameras when clear weather allowed observations at night from March through June.
Information Contacts: Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/); Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/); Yukio Hayakawa, Gunma University, Faculty of Education, Aramaki 4-2, Maebashi 371-8510, Japan.
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2011-2012 eruptions with plumes rising up to 1 km above crater rim
Our last report covered beharior at Suwanose-jima through July 2011 (BGVN 36:07). This report, compiling translated material from the Japan Meteorological Agency (JMA), covers ongoing activity through June 2012, with minor magnitude venting at Otake crater and the tallest plume rising to 1 km over the crater rim. Throughout the reporting period, the volcano's crater produced weak glow at night that was imaged by a high-sensitivity camera. The Alert Level remained at Level 2 (on a scale from 1-5, access to the crater area prohibited due to threat of eruption). As summarized in the text, numbers of A- and B-type events were in the ranges of 11-24 and 62-205, respectively. There were multiple cases of ashfall at [the village 4 km SSW] from the summit crater.
The table below summarizes some other information reported by JMA, including a tally of small eruption heights. Tremor duration extended to over 50 hours during several months and to 132 hours in June 2012.
Monthly coverage. Volcanic earthquakes and tremor continued during July and August 2011 (table 10). In August, seismic activity decreased; A- and B-type events occurred 24 and 62 times, respectively. A-type earthquakes are generally considered to have shallow focal depths; B-type earthquakes, deeper focal depths.
Table 10. A compilation of data on Suwanose-jima during July 2011 through June 2012. "--" indicates data not reported. Data courtesy of JMA.
| Month | Explosive Eruptions | Tremor Duration (hh:mm) | Max. plume height above rim (m) | Other Activity |
| Jul 2011 | 0 | -- | 400 | Prolonged activity |
| Aug 2011 | 0 | 15:23 | 300 | Prolonged activity |
| Sep 2011 | 2 | 64:00 | 300-1,300 | Small eruptions on 8,9,11, and 12 Sep |
| Oct 2011 | 0 | 18:51 | 1,000 | Small eruption on 1 Oct |
| Nov 2011 | 0 | 28:30 | 600 | Small eruption on 15 Nov |
| Dec 2011 | 0 | -- | 400 | -- |
| Jan 2012 | 1 | 69:24 | 300 | -- |
| Feb 2012 | 1 | 00:58 | 400 | -- |
| Mar 2012 | 1 | 00:17 | ~200 | -- |
| Apr 2012 | 0 | 09:26 | 300 | -- |
| May 2012 | 0 | 40:11 | 600 | Very small eruptions on 25,26, and 28-30 May |
| Jun 2012 | 0 | 132:24 | 300 | Very small eruptions |
Explosive eruptions from Otake crater occurred on 9 and 12 September 2011. A temporal increase in seismicity, including intermittent tremor, was observed during 9-14 September, later dropping to background level. Ash fell [in the village] on 7, 9, 12, 15, and 18 September.
Small-scale eruptions were observed in October and November 2011. Ashfall was reported [in the village] on 15 November.
Aerial observations were conducted in cooperation with the Japan Maritime Self Defense Force (JMSDF) on 19 December 2011. They revealed a high temperature area at the center of Otake crater.
GPS measurements showed no remarkable crustal change between January and June 2012. GPS data from Tongama ceased starting in mid-May due to a technical failure.
No explosive eruptions occurred in April 2012. Instruments detected 21 A-type events and 85 B-type events.
During May, there were 11 A-type events and 205 B-type events. Noteable volcanic tremor occurred on 5 and 25-26 May. [Residents in the village] registered ashfall on 25 and 28-30 May.
[Village residents] again reported ashfall on 11 and 13-14 June 2012. During June instruments detected 21 A-type events and 116 B-type events. Volcanic tremor was registered during 2?22 June 2012 (table 10).
Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/).
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Near continuous tremor between July 2012 and March 2013
This report discusses Suwanose-jima (figure 16) during July 2012 through April 2013, an interval with generally abundant tremor, low numbers of earthquakes, weak plumes (less than 0.7 km above the crater rim), and occasional intermittent eruptions. Our previous report on Suwanose-jima discussed seismicity through June 2012 that included volcanic earthquakes and tremor, minor explosions, and plumes which occasionally deposited ash [in the residential area ~4 km SSW of the active crater, administratively part of the multi-island Toshima Village,] as late as June 2012 (BGVN 37:08).
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Figure 16. Satellite image showing the location of Suwanose-jima. Courtesy of Google Earth. |
Recent monthly reports of volcanic activity from the Japan Meteorological Agency (JMA) translated into English resumed in October 2010. Since June 2012, English-translated JMA reports on Suwanose-jima were available online every month through March 2013.
According to JMA, seismic activity at Suwanose-jima remained at low levels between July 2012 and March 2013. Although explosive eruptions have occurred repeatedly in the past, no such eruption occurred during the reporting period. However, JMA reported infrequent tiny eruptions. Volcanic tremor occurred almost continually between 28 September 2012 and March 2013. A high-sensitivity camera often detected a weak night glow during every month. No unusual ground deformation was seen in GPS observation data. Table 11 summarizes tremor activity and other information reported by JMA.
Table 11. A compilation of data on Suwanose-jima between July 2012 and March 2013. '--' indicates data not reported. A-type earthquakes are generally considered to have shallow focal depths; B-type earthquakes, deeper focal depths. An asterisk "*" in the earthquake column indicates that the number of events reported for a specific month conflicts with the number reported for that same month in the sequential monthly JMA report. Data courtesy of JMA.
| Month | Earthquakes | Tremor duration (hours:minutes) | Max plume height (m above crater rim) | Comments |
| Jul 2012 | 29 A-type events, 123 B-type events | 38:5 | 400 | Eruption. |
| Aug 2012 | 17 A-type events, 39 B-type events (or 60 events)* | 0:0 (or 0:1)* | 300 | No eruption. Plume on 19 Aug only. |
| Sep 2012 | 37 A-type events, 86 B-type events (or 74 events)* | 0:1 (or 67:52)* | 300-400 | No eruption. White plumes. 11 Sep aerial observation spotted white plume above Otake crater. |
| Oct 2012 | 22 A-type events, 78 B-type events. | 705:19 | 700 | Tiny intermittent eruptions at Otake crater. According to Tokyo VAAC, an ash plume on 3 Oct drifted SW at altitude of 3 km (i.e. 1.5 km higher than the JMA reported). Ashfall [in the village], 4 km SSW of Otake, on 2 and 5 Oct. |
| Nov 2012 | -- | 720:0 | 500-600 | Tiny intermittent eruptions. Tiny amount of ashfall [in the village] on 25 Nov. |
| Dec 2012 | -- | 622:23 | 500 | Tiny intermittent eruptions on 26th, red hot mass seen. |
| Jan 2013 | -- | 744:0 | 500 | White plumes. |
| Feb 2013 | -- | 672:0 | 500 | M 3.6 earthquake on 19 Feb with aftershocks. Tiny intermittent eruption on 3 Feb. Tiny amount of ashfall [in the village] on 3 Feb. |
| Mar 2013 | -- | -- | 500 | Tremor data unavailable. |
| Apr 2013 | -- | -- | 700 | Small eruption on 13 April. Tremor data unavailable. |
On 8 November 2012, a field survey at Bunka crater revealed no remarkable change in the crater's shape. Infrared images showed no significant change in the crater's temperature distribution. On 26 December 2012, an aerial observation revealed a red-hot lava mass inside Otake crater. This phenomenon has occasionally been observed in past observations.
On 19 February 2013, a M 3.6 earthquake occurred (apparently at Suwanose-jima). The earthquake's maximum seismic intensity on JMA's scale was 3 (felt indoors by most or all people, objects rattle and fall off tables, houses shake strongly and may receive slight damage). In addition, a swarm of ten earthquakes (aftershocks?) with seismic intensities of 1 or greater on JMA's scale were recorded. These earthquakes caused no significant changes in surface phenomena or tiltmeter data. Seismicity remained at low levels, with hypocenters located just beneath the Otake crater.
Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/); Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/).
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Periods with several eruptions per day during April 2013-December 2014
This report covers activity at Suwanose-jima from 1 April 2013 to 31 December 2014. The previous Bulletin report (BGVN 38:04) detailed near-continuous tremor, a few earthquakes, and occasional ash plumes and eruptions during July 2012 through April 2013. This reporting period includes continuous tremor, intervals with several explosions per day, and plumes rising up to 5.5 km altitude. The data was gathered primarily from two key sources: the Tokyo Volcanic Ash Advisory Center (VAAC) and the Japan Meteorological Agency (JMA), who publishes monthly reports on Japanese volcanic activity (URL in Information contacts section).
The map in figure 17 highlights the location of the Otake crater, which was the source of the plumes, explosions, and other activity at Suwanose-jima during this reporting interval. The map was published by the JMA and also depicts the locations of monitoring sites for the volcano.
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Figure 17. A map indicating monitoring sites and topography, with a contour interval of 20 m. The Otake crater is located in the center of the island. Seismometers (circles), infrasonic microphones (circles with crosses), tiltmeters (triangles), GPS (stars), and visual cameras (binoculars) were situated on the nearby slopes by several agencies. The Disaster Prevention Research Institute (DPRI) utilizes the light blue units, the JMA the red units, and the Geospatial Information Authority of Japan (GSI) the orange unit. Source: Iguchi and Ito (date unknown) with slight changes by Bulletin editors. |
Activity during 2013. According to the JMA (monthly reports), the Alert Level at Suwanose-jima constantly remained at 2 (on an increasing scale of 1-5). At night, high-sensitivity cameras regularly observed weak crater glow. A series of almost-continuous tremors began on 28 September 2012 and persisted through 2013.
During the month of April, the JMA noted that the tremor lasted for a total of 677 hours and 50 minutes. On 13 April 2013, the Otake crater had a minor eruption with plumes rising to 0.7 km above the crater.
The Otake crater did not erupt during May and June 2013. In May, white plumes generally rose to 0.2-0.3 km above the crater; the tallest plume reached 0.5 km. There was "no remarkable change in plume activity" in June, according to the JMA. During the month of May, a nearly continuous tremor lasted for a total duration of 704 hours and 54 minutes. It stopped on 1 June 2013 and then resumed on 12 June.
On 9 July 2013, a pilot reported an ash plume to 1.5 km altitude. However, the Tokyo VAAC was unable to detect ash in satellite images. Continuous tremor occurred from mid-June to 15 July and from 24 to 30 July. On 29 July, an earthquake occurred near Suwanose-jima, with a magnitude of 3.2 and a seismic intensity of 2 (an increasing scale of 0-7).
The International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) conducted a field trip to the volcano during 15 and 18 July 2013 (figure 18). They found the volcano quiet, releasing only short, white plumes.
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Figure 18. Photos taken from 16-18 July during a field trip associated with the IAVCEI 2013 Scientific Assembly. Additional photos can be found on Volcano Discovery. (Top) Otake crater, facing NE. A thin, white plume rises from the crater and is shown in greater detail in the zoomed photo on the upper right. (Bottom, left) Crater from which the 1813 subplinian Bunka eruption originated. (Bottom, middle) Flank of old cinder cone within the rift zone. The ground in this area was covered by spatter agglutinate from the 1813 eruption. (Bottom, right) Scoria and ash deposits in the NE cliff of the island. Source: Pfeiffer (2013), labeled by Bulletin editors. |
On 25 August 2013 at 1904 LT, the Otake crater erupted, and intermittent explosive eruptions continued from 26 August onwards. On 27 August, plumes rose to ~1.2 km altitude and drifted NE/SE. On 28 August, ash plumes beginning at 0910 LT rose to altitudes of 1.8-2.1 km, drifting NE and 3-3.7 km altitude, drifting E/NW. There was a total of 16 explosive eruptions during August. The above crater height of the resultant grayish white plumes generally ranged from 0.5-0.8 km, with the tallest plumes reaching ~1.5 km above the crater. Tremor occurred near continuously during 2-4, 11-14, and 25-31 August. Satellites utilized by the VAAC detected ash on 29 August, and from 30 August to 1 September, they detected explosions as well.
During September 2013, the Otake crater erupted explosively six times. Explosions occurred from 5-6 September with ash plumes rising to 1.8-2.1 km altitude, beginning at 0655 LT on the 5th and drifting NNW. On 12 September, ash plumes rose to 1.8 km altitude, drifting NW. During 29-30 September, ash plumes rose to 1.5 km altitude, drifting W and volcanic blocks were scattered around the crater on the 29th. Plumes in September generally rose above the crater to less than 1 km and the maximum height was 1.4 km. Earthquakes were felt near to Suwanose-jima on 10, 21, and 26 September 2013. The seismic intensity was 1 and tremor occurred intermittently.
During October, minor explosions occurred at the Otake crater during 13-15 and 21-22 October. Gray plumes from those eruptions generally rose above the crater to less than 0.6 km, with a maximum height of 1 km above the crater. Earthquakes were felt near the volcano on 9 October 2013. The seismic intensity was 2 and tremor occurred intermittently. On 21 October, an ash plume rose to 1.5 km altitude, heading S.
On 27 November 2013, the Otake crater erupted explosively 7 times, causing a scattering of volcanic projectiles around the crater. The eruption formed a plume that rose 1.8 km altitude, drifting E. In addition, Otake erupted occasionally throughout the month, with gray plumes above the crater generally rising to less than 0.6 km and a maximum plume height of 1 km. Tremor occurred intermittently.
Between 26 and 31 December 2013, Otake erupted 247 times, according to the JMA December 2013 report. From 27-28 December, plumes from Suwanose-jima rose to ~1.5 km altitude, drifting SE. On 28 December, small amounts of ashfall were observed [in the village ~4 km SSW] of Otake. According to the village administration, air shocks rattled windows and sliding doors from 28-29 December and crater glow was observable at night. On 29 December 2013, 125 explosions occurred, along with tremor and airshocks from about 0000 to 0300 LT. This indicated "consecutive eruptions," according to the JMA, with gray plumes rising to 0.6 km above the crater. The eruption ejected volcanic projectiles around the crater.
Activity during 2014. Information for activity during May, July, and October 2014 was unavailable, with an absence of VAAC reports for these intervals. During January, the Otake crater exploded 23 times, with volcanic projectiles scattering around the crater. The Tokyo VAAC noted explosions during 1-3 and 6 January. Between 1 and 2 January, explosions formed plumes to 0.9-1.8 km altitude, drifting SE. The explosions were heard in [the] village until the 3rd. During 8 to 9 January, explosions generated plumes, which rose to 1.2 km altitude and drifted NE/SE. The VAAC noted an explosion on 24 January, generating a plume that rose to 1.8 km altitude. Minor ashfall was observed on 1, 6, and 23 January.
During February 2014, the Otake crater exploded 7 times (on 2, 12, 19, and 23-24 February), with plumes reaching a maximum height of 1.2 km above the crater. On 2 February, the explosion at 1638 LT formed an ash plume to 1.8-3 km altitude that blew SE/SSE. On 12 February, the generated plume rose to 1.2 km altitude and drifted SE, and on 14 February, a plume rose to an altitude of 1.8 km altitude. During 23 to 24 February, plumes rose to 1.8 km altitude and drifted E. Volcanic seismicity for February was high and tremor occurred occasionally.
On 1 March 2014, the Otake crater erupted explosively. All other eruptions during March were minor and sporadic in occurrence. Plumes rose to a maximum height of 0.8 km above the crater. The volcanic seismicity was high and tremor occurred occasionally.
On 29 April, the Otake crater erupted explosively twice and the resulting plumes rose to 1.2 km altitude, heading E. All other eruptions during April were once again minor and sporadic in occurrence. Plumes reached a maximum height of 0.8 km above the crater.
During June 2014, the Otake crater erupted several times, with explosions on 18 June at 2246 LT, on 19 June at 1734 LT with a plume heading E, and on 20 June at 0933 LT. VAAC satellite imagery did not indicate any ash within the plumes.
Between 28 August and 1 September, eruptions resulted in ash plumes rising to 1.8-2.7 km altitude and drifting S, SE, E, and NE. Several eruptions occurred during the first week of September, with ash plumes rising to 1.8-5.5 km altitude on 3 September beginning at 1109 LT, 5.5 km altitude on 4 September at 1833 LT, and 2.1 km altitude on 9 September at 2233 LT.
On 14 November 2014, the Tokyo VAAC reported an explosion, with a plume rising to 1.8 km altitude and drifting SE.
Explosions at Suwanose-jima on 7 December 2014 formed plumes rising to 1.5-1.8 km altitude, drifting E/SE. On 14 December, plumes rose to 1.8 km altitude. and drifted SE.
SO2 emissions. Morita and others (2013) conducted an analysis of SO2 emissions at Suwanose-jima between 20 January and 7 May 2013. Using a UV spectrometer, Ocean Optics USB2000+, they obtained 3 to 15 minute long scans from between 0800 and 1700 LT. The average daily SO2 emission rate was ~700 tons/day (t/d), and ranged between 300 and 1300 t/d. These emission numbers are comparable to those at Suwanose-jima between 1975 and 2006, when the SO2 fluctuated between 300 and 1,130 t/d (Mori and others, 2013). The researchers also found positive correlations between seismic amplitude and released puffs with associated increases in SO2 emissions.
References. Iguchi, M., Ito, K., date unknown, 97. Suwanosejima, Japan Meteorological Agency (URL: http://www.data.jma.go.jp/svd/vois/data/tokyo/STOCK/souran_eng/volcanoes/097_suwanosejima.pdf) [accessed in April 2015]
Mori, T., Shinohara, H., Kazahaya, K., Hirabayashi, J., Matsushima, T., Mori, T., Ohwada, M., Masanobu, O., Iino, H., Miyashita, M., 2013, Time-averaged SO2 fluxes of subduction-zone volcanoes: Example of a 32-year exhaustive survey for Japanese volcanoes, 16 August 2013, Journal of Geophysical Research: Atmospheres (URL: http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50591/full)
Morita, M., Mori, T., Iguchi, M., Nishimura, T., 2013, Continuous monitoring of sulfur dioxide emission rate at Suwanosejima volcano, Japan, Fall 2013, American Geophysical Union (URL: http://adsabs.harvard.edu/abs/2013AGUFM.V43B2875M)
Pfeiffer, T., 2013, Excursion to Suwanose-jima volcano (Tokara Islands, Japan) - photos from the IAVCEI 2013 field trip A3, July 2013, Volcano Discovery (URL: http://www.volcanodiscovery.com/suwanosejima/photos/july2013/fieldtrip.html) [accessed in April 2015]
Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html; Monthly report URL: http://www.data.jma.go.jp/svd/vois/data/tokyo/eng/volcano_activity/monthly.htm); Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/)
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Occasional ash plumes during January-September 2015
Continuous tremor, intervals with several explosions per day, and plumes rising to 5.5 km altitude were observed at Suwanosejima between 1 April 2013 and 14 December 2014 (BGVN 39:11). The data for this report, covering 5 January-11 September 2015, was gathered primarily from two key sources: the Tokyo Volcanic Ash Advisory Center (VAAC) and the Japan Meteorological Agency (JMA). Throughout the entire reporting period, no MODVOLC thermal anomalies were recorded, although the hazard status remained at Alert Level 2 (Do not approach the crater), on an increasing scale of 1-5. The Otake (also O-take) crater (figure 1) was the site of much of the activity during 2015.
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Figure 19. Simplified map of the geology of Suwanosejima. The active crater, O-take (Oc), appears in the center of the small, sparsely populated island. Courtesy of Taketo Shimano. |
In its Monthly Volcanic Activity Report for January 2015, JMA noted four explosive eruptions at the Otake crater, in addition to other occasional non-explosive eruptions. Grayish plumes accompanying the eruption rose as high as 1 km above the crater rim. On 25 January a field survey revealed a pit in the southeastern portion of the Otake crater which had formed since the previous survey on 8 November 2012.
Plumes in 2015 were reported by the VAAC in the months of January, February, April, July, August, and September. JMA served as the primary source for all of these VAAC notices; any additional sources are noted. The Tokyo VAAC reported that on 5 January ash plumes rose to altitudes of 1.5-1.8 km and drifted NE and SE, and were also observed by pilots. The VAAC also reported an explosion on 25 January, the same day as the field survey.
The Tokyo VAAC reported that during 11-12 and 14-15 February ash plumes rose to altitudes of 1.8-2.1 km and drifted E. JMA's monthly report for February 2015 indicated that twelve explosions occurred at Otake crater, in addition to occasional, non-explosive events. Grayish plumes accompanying the explosions rose as high as 1,500 m above the crater rim. According to the Suwanosejima branch of the Toshima Village administration, ash fall was observed at Kiriishi port (located ~3.5 km S. of Otake) on 26 February.
A very small eruption at the Otake crater on 5 March 2015 was noted by JMA. An event on 13 April reported by the Tokyo VAAC generated a plume that rose to an altitude of 2.1 km and drifted N. Explosions during 24-25 April generated plumes that rose to altitudes of 1.8-2.1 km and drifted N and SE.
JMA reported a continued high activity level at the Otake crater with very small eruptions recorded on 5 and 17 May 2015. No explosions were observed at the Otake crater in June. The Tokyo VAAC reported that ash plumes from small eruptions at Otake on 30-31 July rose to altitudes of 2.1-3 km and drifted E, SW, and W, as reported by pilots and seen in satellite data. Grayish plumes accompanying the eruption rose as high as 1,300 m above the crater rim. According to the Suwanosejima branch of the Toshima Village administration, ashfall was observed in a village ~4 km SSW of Otake on 31 July.
JMA's August 2015 report described small, occasional, non-explosive events at the Otake crater, with accompanying grayish plumes rising as high as 1.2 km above the crater rim. Volcanic "glow" was observed at the Otake crater occasionally at night with a high-sensitivity camera. According to the Toshima Village administration, ashfall 4 km SSW of Otake was again present on 1, 2, and 9 August. The Tokyo VAAC reported that ash plumes identified in satellite images rose to an altitude of 4 km on 2 August, and to 1.8 km on 21 August that drifted SE.
In the September 2015 report, JMA noted that volcanic activity had remained at high levels, with 89 explosions recorded at the Otake crater; 69 of those were on 24 September, the first time more than 50 explosions a day had been observed since 30 December 2013. Plumes accompanying the events rose as high as 1,500 m above the crater rim. Crater incandescence was observed at night with a thermal camera. According to the Toshima Village administration, ashfall was once again observed in a village 4 km SSW on 7 September. The Tokyo VAAC reported that on 13 September ash plumes rose to an altitude of 1.8 km and drifted SE. JMA noted that parts of local structures shook in association with explosions that occurred on 24 September. Explosions and rumbling were heard on the island.
Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/); Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/).
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Persistent ash plumes, explosions, and Strombolian activity during September 2015-December 2016
Suwanosejima, an andesitic stratovolcano in Japan's northern Ryukyu Islands, was intermittently active for much of the 20th century, producing ash plumes, Strombolian eruptions, and ash deposits. Continuous activity since October 2004 has consisted generally of multiple ash plumes most months rising a few hundred meters above the summit to altitudes between 1 and 2 km, and tens of reported explosions. Activity between January and September 2015 included small eruptions in July and August that produced ash plumes rising to 3-4 km altitude. Increased activity beginning in August 2015 included incandescence at the crater and increased explosive activity with incandescence in September; 89 explosions occurred that month, and ash fell in the village 4 km SSW (BGVN 42:01). Eruptive activity for the period of September 2015-December 2016 included intermittent explosions, ash plumes up to 4.3 km altitude, ashfall within a 5-km radius, and Strombolian activity. Information is provided primarily by the Japan Meteorological Agency (JMA), and the Tokyo Volcanic Ash Advisory Center (VAAC).
Activity during September-December 2015. Numerous explosions were reported by the JMA during 24-30 September. The Tokyo VAAC reported a plume at 2.1 km altitude extending SE on 24 September; subsequent reports noted there were no observations of ash emissions or plumes in satellite data during that time, and no further VAAC reports were issued after 30 September (until January 2016).
JMA reported that explosions at the Otake crater on 2, 13, and 31 October 2015 produced gray-and-white emissions and rose a maximum of 800 m above the summit (at ~800 m elevation). Explosions occurred on 1 and 20 November as well; the plume rose 1 km above the crater rim on 1 November. Ashfall was confirmed in the small village 4 km SSW after both events. There were no explosions reported during December 2015; only steam emissions rose 600 m above the summit crater, and rumbling was heard on 12 December from the nearby settlement. Incandescence was visible with a thermal camera at night during September-December 2015.
Activity during 2016. According to JMA, explosions and intermittent emissions occurred during most months of 2016 (table 12). Ashfall in the village 4 km SSW of the summit was reported during January-April, July-August, and October-November. Steam-and-ash plume heights ranged from 800 to 2,700 m above the crater rim. The number of monthly seismic events was low in January (25), increasing to a maximum of 1,195 in April. It dropped below 200 by July, and below 100 during November and December. Incandescence at night was reported often every month. An overflight on 31 May 2016 revealed a steam plume rising 400 m above Otake crater (figure 20). Strombolian activity on 15 September and 23 November 2016 ejected incandescent blocks onto the crater rim (figure 21). An ash emission on 25 November sent gray and white ash and steam 1,800 m above the crater rim (figure 22). Incandescent blocks from an explosion were also observed on 17 December.
Table 12. Activity at Suwanosejima during 2016 reported by JMA. Times are local.
| Month | No. of explosions | Emission events | Max plume height (m above crater) | Dates of ashfall in village 4 km SSW | No. of seismic events | Other activity detail |
| Jan 2016 | 1 | Yes, small | -- | 22, 23 | 25 | Occasional incandescence at night; explosion at 2114 on 6 Jan. |
| Feb 2016 | 0 | Occasional small | 800 m | 22 | 64 | Occasional incandescence at night. |
| Mar 2016 | 13 | 1,700 m | 7, 20, 21 | 170 | Incandescence at night; shockwaves felt 20-21 Mar. | |
| Apr 2016 | 14 | -- | 1,700 m | 11, 15, 18, 19 | 1,195 | Incandescence at night; occasional rumbling; seismicity increased 24-26 Apr. |
| May 2016 | 5 | Steam plumes | 1,200 m | None | 396 | Incandescence at night; overflight (figure 20); steam plume 400 m above crater on 31 May drifted NE. |
| Jun 2016 | 0 | Occasional | 1,900m | None | 606 | Incandescence at night. |
| Jul 2016 | 0 | Occasional | 1,900 m | 23 | 142 | Incandescence at night. |
| Aug 2016 | 26 | -- | 2,700 m on 12 and 28 | 1, 2 | 171 | Incandescence at night; tephra around crater on 12 and 28 Aug; infrasound on 13, 14 Aug; rumbling on 25 Aug. |
| Sep 2016 | 1 | 3 | Ash to 1,900 m on 17, steam to 2,400 m on 5 | None | 106 | Incandescence almost every day; Strombolian activity and explosion at 2305 on 15 Sep (figure 21). |
| Oct 2016 | 0 | Occasional | 1,200 m | 6, 30 | 102 | Incandescence almost every day. |
| Nov 2016 | 11 | Occasional ash emissions | 1,800 m | 5, 6, 26, 29 | 56 | Constant incandescence; Strombolian explosion at 2325 on 23 Nov sent blocks around crater (figure 22). |
| Dec 2016 | 7 | Occasional ash emissions | 2,500 m at 1356 on 13 | None | 33 | Incandescence at night; large explosion at 2020 on 13 Dec; incandescent blocks on 17 Dec. |
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Figure 20. Aerial photos of Otake crater at Suwanosejima on 31 May 2016. Upper image is the close-up view outlined in red below. Courtesy of JMA (Volcanic activity commentary on Suwanosejima, May 2016). |
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Figure 21. Strombolian activity and explosion at Suwanosejima on 15 September 2016 sent a large incandescent block outside the crater rim (center left). Courtesy of JMA "Paris tree" webcam (Volcanic activity commentary on Suwanosejima, September 2016). |
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Figure 22. Explosive activity at Suwanosejima during November 2016 produced Strombolian activity and ash emissions. A Strombolian explosion on 23 November (top photo) sent incandescent blocks around the crater rim (left center, viewed by the JMA "Nogi" webcam). An ash emission on 25 November (bottom photo) sent ash and steam 1,800 m above the crater rim (viewed by the JMA "Campsite" webcam). Courtesy of JMA (Volcanic activity commentary on Suwanosejima, November 2016). |
The Tokyo VAAC also reported information about ash plumes and explosions during 2016 (table 13). Explosions were reported during every month of 2016 except February, and ranged from two in January to 19 in August. Most plume heights were lower than 2.7 km altitude. Exceptions included: an explosion on 1 August produced an ash plume that rose to 3.4 km altitude and drifted S; a plume rose to 3 km on 29 November and also drifted S; and the largest of the year, an ash plume that rose to 4.3 km altitude and drifted E, on 13 December (figure 23).
MODVOLC thermal alerts were reported on 20 April, 4 May (3), and 17 May 2016.
Table 13. Summary of activity reported at Suwanosejima during 2016 by the Tokyo VAAC. Time in UTC.
| Month | Explosion Count | Explosion Days | Plume Heights | Drift Directions |
| Jan 2016 | 2 | 4, 6 | 1.5 km | SE |
| Feb 2016 | 0 | -- | -- | -- |
| Mar 2016 | 14 | 2 (2), 4, 6, 7 (2), 10, 21, 22 (2), 23, 26 (2), 30 | 1.2-2.4 km | SE, W, N |
| Apr 2016 | 13 | 5, 10, 14 (2), 15, 17 (2), 18, 19 (3), 20, 21 | 1-2.4 km | E, W, SE, S, N |
| May 2016 | 5 | 3 (2), 4 (2), 18 | 1.5-2.1 km | E, SE, W |
| Jun 2016 | 4 | 13 (3), 14 | 1.8-2.7 km | E |
| Jul 2016 | 4 | 18 (2), 22, 31 | 1.5-2.7 km | NE, E, N, NW, W |
| Aug 2016 | 19 | 1 (3), 10 (3), 11, 12, 14 (2), 17, 25, 26 (2), 27 (2), 28 (2), 31 | 1.0-3.4 km | SW, SE, W, NW |
| Sep 2016 | 2 | 15, 16 | 2.7 km | W |
| Oct 2016 | 5 | 6 (2), 25 (2), 26 | 1.5-1.8 km | E, S, NE |
| Nov 2016 | 18 | 5, 6, 8, 10 (2), 11 (3), 12 (2), 16, 17, 19, 20, 23, 25 (2), 29 | 1.2-2.1, 3.0 km on 29 | E, SW, SE, S, W |
| Dec 2016 | 4 | 13 (2), 16, 17 | 4.3 on 13, 1.8 km | NE, SE, SW, W |
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Figure 23. The largest ash explosion of 2016 at Suwanosejima (viewed from the JMA "Parquet" webcam) occurred on 13 December 2016 and sent a plume to 4.3 km altitude (3,500 m above the crater rim). Courtesy of JMA (Volcanic activity commentary on Suwanosejima, December 2016). |
Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).
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Large explosions with ash plumes and Strombolian activity continue during 2017
Suwanosejima, an andesitic stratovolcano in Japan's northern Ryukyu Islands, was intermittently active for much of the 20th century, producing ash plumes, Strombolian explosions, and ash deposits. Continuous activity since October 2004 (figure 24) has consisted generally of multiple ash plumes most months rising hundreds of meters above the summit to altitudes between 1 and 3 km, and tens of reported explosions. The rate of activity began increasing during 2014; the frequency of explosions and the height of the plumes have continued to increase through 2017, which is covered in this report. Information is provided primarily by the Japan Meteorological Agency (JMA), and the Tokyo Volcanic Ash Advisory Center (VAAC).
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Figure 24. Eruptive history at Suwanosejima from January 2003-December 2017. Black bars represent the height of the emissions in meters above the crater rim, gray volcanoes indicate an explosion, usually accompanied by an ash plume, and the red volcanoes represent large explosions with ash plumes. Courtesy of JMA (Suwanosejima volcanic activity report, December 2017). |
Activity at Suwanosejima has been persistent and generally increasing during 2014-2017 (figure 25). During 2017, ash emissions rose from a few hundred to nearly 3 km above the Otake crater rim. Large explosions were reported 32 times by JMA, including 12 during August. Most explosions sent ash emissions to less than 1,000 m above the crater rim, but the highest ash plume, on 3 August 2017, rose 2.8 km above the crater rim, and was the highest recorded since observations began in 2003. Incandescence was observed at the crater from a thermal camera throughout the year and was witnessed locally many times. Many of the explosions, large and small, were heard in the nearby village. Ashfall was confirmed in the village to the SSW on nine different occasions during the year.
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Figure 25. Eruptive history at Suwanosejima for 2014-2017. Black bars represent height of steam, gas, or ash plumes in meters above crater rim, gray arrows or volcanoes represent an explosion, usually accompanied by an ash plume, red arrows or volcanoes represent a large explosion with an ash plume, red bars or orange diamonds indicate incandescence observed in webcams. From top to bottom: Eruptive activity during 2014, 2015, 2016, and 2017. Courtesy of JMA (Suwanosejima volcanic activity reports, December 2014, 2015, 2016, and 2017). |
Activity during January-April 2017. There were no large explosions at Suwanosejima during January 2017, but occasional minor ash emissions rose as high as 1,300 m above the Otake crater rim. Incandescence was visible from the webcam on most clear nights. Ashfall was reported in the village 4 km S on 17 and 26 January. The Tokyo VAAC reported ash emissions four times in January. Ash plumes rose to 1.2 km altitude and drifted SE on 4 January; to 1.8 km and drifted W on 5 January; to 1.2 km and drifted S on 16-17 January; and to 2.1 km and drifted SE on 25 January.
In contrast with January, five large explosions were reported by JMA during February 2017. The first, on 9 February, sent an ash plume to 700 m above the crater rim. An ash emission on 18 February rose to 1,200 m above the rim (figure 26). People in the nearby village reported hearing explosions on 18, 20, 27, and 28 February. The largest explosions occurred during 27-28 February when ejecta was scattered 600 m from the crater rim. The Tokyo VAAC reported ash emissions drifting SE several times: on 9 February at 1.5 km altitude, on 16 and 17 February at 1.8 km, and during 27-28 February at 1.5 km.
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Figure 26. An ash emission from Suwanosejima was captured by the 'Campground' webcam on 18 February 2017. Courtesy of JMA (Suwanosejima volcanic activity report, February 2017). |
Intermittent ash emissions occurred during March 2017, but no large explosive events were reported. Ejecta was scattered around the edge of the crater on 4 March and an ash plume rose 1,000 m. Small ash plumes were noted rising 900 m on 12 and 15 March; explosions were heard in the village on 14 and 16 March, and ashfall was reported there on 25 March. Incandescence was observed at the summit intermittently throughout the month. During a field survey on 21 and 22 March, JMA noted minor thermal anomalies at the Otake Crater, the N slope of the Otake crater, and just above the coastline on the E flank (figure 27). The Tokyo VAAC reported ash emissions three times during March; on 3 March ash plumes rose to 1.5-1.8 km altitude and drifted SE and on both 28 and 31 March they rose to 1.8 km altitude and drifted SE and E.
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Figure 27. Thermal anomalies were apparent from the Otake crater (upper left), the north slope of the crater (upper right), and just above the coastline on the E flank (lower left) in this thermal image of Suwanosejima taken on 22 March 2017 from the NE. Courtesy of JMA (Suwanosejima volcanic activity report, March 2017). |
Only minor ash emissions and occasional incandescence was reported during April 2017. Two emission events on 1 April sent ash plumes to 1,200 m above the crater rim. A tremor that lasted nine minutes occurred on 11 April and a small seismic swarm was recorded on 13 April. Small explosions were also reported on 17 and 19 April, with the 19 April event heard at the nearby village; another small explosion was reported on 30 April. There were no reports issued by the Tokyo VAAC.
Activity during May-August 2017. Activity increased slightly during May 2017; two large explosions were recorded by JMA. A small explosion was reported on 1 May, and the highest plume rose to 1,900 m above the crater rim on 10 May during a larger event. Incandescence was observed from the local village on 16 May, and explosions were heard from the village on 16 and 18 May, and again on 28 and 29 May; no ashfall was reported. The Tokyo VAAC reported ash emissions on 7, 8, and 10 May. On 7 May they reported an ash plume located 45 km S at 1 km altitude extending SW. A few hours later ash extended N at 1.5 km. An explosion on 8 May sent an ash plume to 2.1 km where it remained stationary over the volcano for much of the day before dissipating. A higher ash plume was reported on 10 May at 2.7 km altitude drifting E.
Small ash explosions occurred at Otake Crater on 8 and 21 June 2017, but there were no larger explosive events. Ash plume heights rose to only 600 m above the crater rim, and occasional nighttime incandescence was reported. No reports were issued by the Tokyo VAAC. JMA reported that the highest ash plume during July rose 2.1 km above the summit crater on 17 July, but no large explosions were recorded. Incandescence was observed intermittently throughout the month. A small explosion on 2 July sent an ash plume to 1.9 km above the crater rim. Intermittent ash emissions were noted during 17-19, 22 and 25 July. The Tokyo VAAC reported ash emissions during 2 and 16-18 July. They reported the plumes on 2 July at 1.8-2.4 km altitude, extending N for most of the day. A new explosion on 16 July sent an ash plume to 2.7 km altitude that drifted E. Intermittent ash emissions continued to drift E through 18 July at altitudes ranging from 1.8-2.1 km.
Activity increased substantially during August 2017; JMA reported 12 large explosions, nine of which occurred during the last week. Ashfall was reported in the nearby village on 2 August. The highest plume of the month was reported on 3 August, 2.8 km above the crater rim. Explosions were heard in the village on 3 and 19 August. A small explosion was reported on 12 August. Large explosions occurred on 19, 20, and 24 August in addition to the nine events during the last week. A single MODVOLC thermal alert was reported on 18 August, and the MIROVA system reported thermal anomalies during several days of the last week of the month (figure 28). The Washington VAAC reported ash on 1 August that rose to 2.4 km altitude and drifted SW. A higher plume on 3 August rose to 3.7 km and drifted W. They reported another ash plume that first rose to 3.0 km on 24 August; subsequent emissions that day were drifting NE at 2.1-2.4 km altitude. A new plume on 25 August extended E at 2.4 km. Continuing ash emissions from multiple explosions during 28-31 August rose to 1.2-3.0 km altitude and drifted SE.
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Figure 28. Log Radiative Power plot from the MIROVA project for Suwanosejima for 24 May 2017-15 February 2018 shows increased thermal activity during late August 2017, and intermittent pulses of activity from late May-September. Courtesy of MIROVA. |
Activity during September-December 2017. Four large explosions were recorded during the first week of September 2017, after which a number of smaller ash emission events were reported. Ashfall was reported four times in the nearby village on 2, 4, 29, and 30 September. The Tokyo VAAC reported explosions on 1, 4, 6, and 29 September. The ash plume from the explosion on 6 September rose to 1.5 km altitude and drifted E; on 29 September, it rose to 2.4 km altitude, also drifting E.
JMA reported four large explosions during October 2017. Two explosions occurred on 11 October; one of the ash plumes rose 1,900 m above the crater rim (figure 29). Explosions were heard in the nearby village on 12 and 31 October, and ashfall was reported on 13 October. During the large explosion of 31 October incandescent ejecta was scattered around the crater rim and the ash plume rose 1,900 m. The Tokyo VAAC reported an explosion with ash on 10 October (UTC) that rose to 2.7 km altitude and remained stationary until dissipating a few hours later. They noted that the explosion on 31 October produced a plume that rose over 1.5 km and drifted NW.
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Figure 29. An ash plume from an explosion on 11 October 2017 rises 1.9 km above the Otake crater of Suwanosejima. Courtesy of JMA (Suwanosejima volcanic activity report, October 2017). |
JMA reported five large explosions during November 2017. Incandescent ejecta was seen around the crater rim during the explosion of 1 November, and the plume rose to 2 km above the rim. Loud explosions were heard from the nearby village on 3, 5, 6, 15, and 16 November, and ashfall was reported there on 14, 15, and 20 November. A small explosion was reported on 10 November; intermittent explosions with ash plumes rising 700 m were observed on 20 and 21 November. The Tokyo VAAC reported ash plumes at 1.5 km drifting W on 1 and 5 November, and at 1.8 km altitude drifting NW on 10 November, the last VAAC report issued for 2017.
Only small explosions were reported from Otake crater during December 2017. The highest plume rose 700 m above the crater rim. Small explosions were heard a number of times in the nearby village on 8-9, 11-13, and 26-30 December. JMA scientists visiting during 8-10 December heard intermittent explosions and witnessed incandescence visible to the naked eye. They also observed ashfall in the village on the morning of 10 December. During a field survey on 14 December, no significant changes were noted from the previous survey in March 2017 (figures 30 and 31).
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Figure 30. The summit of Suwanosejima with steam rising from Otake Crater taken from the W on 14 December 2017. Courtesy of JMA (Suwanosejima volcanic activity report, December 2017). |
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Figure 31. Steam rises from the Otake Crater of Suwanosejima viewed from the E on 14 December 2017. Courtesy of JMA (Suwanosejima volcanic activity report, December 2017). |
Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); Tokyo Volcanic Ash Advisory Center (VAAC), 1-3-4 Otemachi, Chiyoda-ku, Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).
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Intermittent ash emission continues from January through June 2018
Suwanosejima volcano is located in the northern Ryukyu Islands in the south of Japan and has been on Alert Level 2 since December 2007. This report is a summary of activity for the period January to June 2018 and is based on information from the Japan Meteorological Agency (JMA) along with Tokyo VAAC notices.
During the reporting period, the active Otake crater produced intermittent explosions that scattered ejecta around the crater and ash plumes to an altitude of 1.5-3 km. Ashfall was reported in a village 4 km away on 10 days during January-May 2018 (table 14). Incandescence was visible at night using monitoring equipment. Ash plumes were noted by the Tokyo Volcanic Ash Advisory Center (VAAC) throughout the reporting period (figure 32, table 15).
Table 14. Reported explosion information for Suwanosejima recorded in JMA monthly reports.
| Month | No. of explosions | Max plume height (m above crater) | Dates of ashfall in village 4 km SSW | No. of seismic events | Other daily activity detail |
| Jan 2018 | 0 | 1,100 | 27, 31 | 97 | Incandescence at night. |
| Feb 2018 | 1 | 1,100 | 2, 3 | 100 | Incandescence at night. |
| Mar 2018 | 9 | 2,200 | 25, 29 | 251 | Incandescence at night. Ejecta scattered around the crater. |
| Apr 2018 | 8 | 2,000 | 18, 28, 29 | 62 | Incandescence at night. |
| May 2018 | 2 | 1,100 | 14 | 90 | Incandescence at night. Ejecta scattered around the crater. |
| Jun 2018 | -- | 900 | -- | 275 | Incandescence at night. |
Table 15. Number of Volcanic Ash Advisories, explosion dates, and plume heights for activity at Suwanosejima. The numbers in parentheses indicate the number of events on that date; the VAACs issued column does not include advisories that note a continued episode. Drift directions were highly variable. Data courtesy of Tokyo VAAC.
| Month | VAAs issued | VAA dates | Plume heights |
| Jan 2018 | 1 | 15 | 1.8 km |
| Feb 2018 | 1 | 2 | 1.2 km |
| Mar 2018 | 22 | 17, 22(3), 23, 25(2), 26(5), 27(5), 28(3), 29(2) | 1.2-3.6 km |
| Apr 2018 | 16 | 1, 2, 3, 4(4), 5(2), 8, 11, 24, 27, 28(2) | 1.2-2.4 km |
| May 2018 | 3 | 1, 4, 15 | 1-1.8 km |
| Jun 2018 | 1 | 1 | -- |
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Figure 32. An ash plume at Suwanosejima reached 1 km above the crater on 3 February 2018. Image captured by the Kyanpuba webcam, courtesy of JMA (February 2018 monthly report). |
Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); Tokyo Volcanic Ash Advisory Center (VAAC), 1-3-4 Otemachi, Chiyoda-ku, Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/).
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Multiple explosive events with incandescence and ash plumes during November 2018
Suwanosejima, an andesitic stratovolcano in Japan's northern Ryukyu Islands, was intermittently active for much of the 20th century, producing ash plumes, Strombolian explosions, and ash deposits. Continuous activity since October 2004 has produced intermittent explosions, generating ash plumes in most months that rise hundreds of meters above the summit to altitudes between 1 and 3 km. Ongoing activity for the second half of 2018 is covered in this report with information provided by the Japan Meteorological Agency (JMA) and the Tokyo Volcanic Ash Advisory Center (VAAC).
Activity during July-December 2018 was intermittent with explosions reported twice in September and 21 times during November. Incandescent activity was observed a few times each month, increasing significantly during November. Thermal data support a similar pattern of activity; the MIROVA thermal anomaly graph indicated intermittent activity through the period that was most frequent during October and November (figure 33). MODVOLC thermal alerts were issued once in September (9), three times in October (7, 21), and four times on 14 and 15 November.
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Figure 33. MIROVA thermal data for Suwanosejima from 7 February through December 2018 indicated intermittent activity at the summit that increased to more significant activity during October and November before declining by the end of the year. Courtesy of MIROVA. |
There were no explosions at Suwanosejima during July or August 2018; steam plumes rose 900-1,000 m above the crater rim and incandescence was intermittently observed on clear nights. During September incandescence was also observed at night; in addition, explosions were reported on 12 and 13 September, with ash plumes rising 1,100 m above the crater rim. October was again quiet with no explosions, only steam plumes rising 800 m, and occasional incandescence at night, although thermal activity increased (figure 33).
More intense activity resumed during November 2018 with 21 explosions reported. On 9 and 14 November tephra was ejected up to 700 m from the Otake crater. The Tokyo VAAC reported an ash plume visible in satellite imagery at 2.4 km altitude moving E on 14 November. The next day, a plume was reported at 2.7 km altitude drifting NW but it was not visible in satellite imagery. JMA reported gray ash plumes that rose up to 2,000 m above the crater rim on 16 and 23 November (figure 34). The ash plume on 23 November was visible in satellite imagery drifting N at 2.7 km altitude. On 30 November the Tokyo VAAC reported an ash plume visible in satellite data drifting SE at 2.4 km altitude. Incandescence was often observed at night from the webcams throughout the month. Ashfall was confirmed in the village 4 km SSW on 14, 17, and 23 November, and sounds were reported on 20 November.
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Figure 34. Ash plumes rose 2,000 m above the crater rim at Suwanosejima on 23 November 2018 as seen with the 'campsite' webcam. Courtesy of JMA (Volcanic activity commentary (November, 2018) of Suwanose Island). |
During December 2018, no explosive eruptions were reported, but an ash plume rose 1,800 m above the summit on 26 December. Incandescence was observed on clear nights in the webcam. Throughout 2018, a total of 42 explosive events were reported; 21 of them occurred during November (figure 35).
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Figure 35. Eruptive activity at Suwanosejima during 2018. Black bars represent heights of steam, gas, or ash plumes in meters above crater rim (left axis), gray volcanoes along the top represent explosions, usually accompanied by ash plumes, red volcanoes represent large explosions with ash plumes, orange diamonds indicate incandescence observed in webcams. Courtesy of JMA (Volcanic activity of Suwanose Island in 2018). |
Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); Tokyo Volcanic Ash Advisory Center (VAAC), 1-3-4 Otemachi, Chiyoda-ku, Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/).
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Small ash plumes continued during January through June 2019
Suwanosejima is an active volcanic island south of Japan in the Ryuku islands with recent activity centered at Otake crater. The current eruption began in October 2004 and activity has mostly consisted of small ash plumes, ballistic ejecta, and visible incandescence at night. This report summarizes activity during January through June 2019 and is based on reports by the Japan Meteorological Agency (JMA), and various satellite data.
Thermal activity recorded by the MIROVA system was low through January and February after a decline in November (figure 36), shown in Sentined-2 thermal infrared imagery as originating at a vent in the Otake crater (figure 37). During January an explosive event was observed at 1727 on the 3rd, producing a gray plume that rose 600 m above the crater. A white gas-and-steam plume rose to 1.5 km above the crater and nighttime incandescence was observed throughout the month. Reduced activity continued through February with no reported explosive eruptions and light gray plumes up to 900 m above the crater. Incandescence continued to be recorded at night using a sensitive surveillance camera.
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Figure 36. MIROVA log radiative power plot of MODIS thermal infrared data at Suwanosejima during September 2018 through June 2019. There was reduced activity in 2019 with periods of more frequent anomalies during March and June. Courtesy of MIROVA. |
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Figure 37. A Sentinel-2 thermal satellite image shows Suwanosejima with the active Otake crater in the center with elevated temperatures shown as bright orange/yellow. There is a light area next to the vent that may be a gas plume. False color (urban) satellite image (bands 12, 11, 4) courtesy of Sentinel Hub Playground. |
There was an increase in thermal energy detected by the MIROVA system in mid-March and there was a MODVOLC thermal alert on the 15th. Occasional small explosions occurred but no larger explosive events were recorded. A white plume was noted on the 27th rising to 900 m above the crater and an event at 1048 on the 30th produced a light-gray plume that rose to 800 m. Incandescence was only observed using a sensitive camera at night (figure 38).
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Figure 38. Incandescence from the Suwanosejima Otake crater reflecting in clouds above the volcano. Courtesy of JMA (Volcanic activity of Suwanosejima March 2019). |
No explosive events were observed through April. A white gas-and-steam plume rose to 1,200 m above the crater on the 19th and incandescence continued intermittently. Minor explosions were recorded on 5, 30, and 31 May, but no larger explosive events were observed during the month. The event on the 30th produced ash plume that reached 1.1 km above the crater. Similar activity continued through June with one explosive event occurring on the 2nd. Overall, there was a reduction in the number of ash plumes erupted during this period compared to previous months (figure 39).
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Figure 39. Observed activity at Suwanosejima for the year ending in July 2019. The black vertical bars represent steam, gas, or ash plume heights (scale in meters on the left axis), yellow diamonds represent incandescence observed in webcams, gray volcano symbols along the top are explosions accompanied by ash plumes, red volcano symbols represent large explosions with ash plumes. Courtesy of JMA (Volcanic activity of Suwanosejima June 2019). |
Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).
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Explosions, ash emissions, and summit incandescence in July-December 2019
Suwanosejima, located south of Japan in the northern Ryukyu Islands, is an active andesitic stratovolcano that has had continuous activity since October 2004, typically producing ash plumes and Strombolian explosions. Much of this activity is focused within the Otake crater. This report updates information during July through December 2019 using monthly reports from the Japan Meteorological Agency (JMA), the Tokyo Volcanic Ash Advisory Center (VAAC), and various satellite data.
White gas-and-steam plumes rose from Suwanosejima on 26 July 2019, 30-31 August, 1-6, 10, and 20-27 September, reaching a maximum altitude of 2.4 km on 10 September, according to Tokyo VAAC advisories. Intermittent gray-white plumes were observed rising from the summit during October through December (figure 40).
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Figure 40. Surveillance camera images of white gas-and-steam emissions rising from Suwanosejima on 10 December 2019 (left) and up to 1.8 km above the crater rim on 28 December (right). At night, summit incandescence was also observed on 10 December. Courtesy of JMA. |
An explosion that occurred at 2331 on 1 August 2019 ejected material 400 m from the crater while other eruptions on 3-6 and 26 August produced ash plumes that rose up to a maximum altitude of 2.1 km and drifted generally NW according to the Tokyo VAAC report. JMA reported eruptions and summit incandescence in September accompanied by white gas-and-steam plumes, but no explosions were noted. Eruptions on 19 and 29 October produced ash plumes that rose 300 and 800 m above the crater rim, resulting in ashfall in Toshima (4 km SW), according to the Toshima Village Office, Suwanosejima Branch Office. Another eruption on 30 October produced a similar gray-white plume rising 800 m above the crater rim but did not result in ashfall. Similar activity continued in November with eruptions on 5-7 and 13-15 November producing grayish-white plumes rising 900 m and 1.5 km above the crater rim and frequent crater incandescence. Ashfall was reported in Toshima Village on 19 and 20 November; the 20 November eruption ejected material 200 m from the Otake crater.
Field surveys on 14 and 18 December using an infrared thermal imaging system to the E of Suwanose Island showed hotspots around the Otake crater, on the N slope of the crater, and on the upper part of the E coastline. GNSS (Global Navigation Satellite Systems) observations on 15 and 17 December showed a slight change in the baseline length. After 2122 on 25-26 and 31 December, 23 eruptions, nine of which were explosive were reported, producing gray-white plumes that rose 800-1,800 m above the crater rim and ejected material up to 600 m from the Otake crater. JMA reported volcanic tremors occurred intermittently throughout this reporting period.
Incandescence at the summit crater was occasionally visible at night during July through December 2019, as recorded by webcam images and reported by JMA (figure 41). MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data showed weak thermal anomalies that occurred dominantly in November with little to no activity recorded between July and October (figure 42). Two Sentinel-2 thermal satellite images in early November and late December showed thermal hotspots within the summit crater (figure 43).
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Figure 41. Surveillance camera image of summit incandescence at Suwanosejima on 31 October 2019. Courtesy of JMA. |
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Figure 42. Weak thermal anomalies at Suwanosejima during January-December 2019 as recorded by the MIROVA system (Log Radiative Power) dominantly occurred in mid-March, late May to mid-June, and November, with two hotspots detected in late September and late December. Courtesy of MIROVA. |
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Figure 43. Sentinel-2 thermal satellite images showing small thermal anomalies (bright yellow-orange) within the Otake crater at Suwanosejima on 8 November 2019 (left) and faintly on 23 December 2019 behind clouds (right). Both images with "Atmospheric penetration" (bands 12, 11, 8A) rendering; courtesy of Sentinel Hub Playground. |
Information Contacts: Japan Meteorological Agency (JMA), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Tokyo Volcanic Ash Advisory Center (VAAC), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).
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Frequent explosions, ash plumes, and summit incandescence in January-June 2020
Suwanosejima is an active stratovolcano located in the northern Ryukyu Islands. Volcanism has previously been characterized by Strombolian explosions, ash plumes, and summit incandescence (BGVN 45:01), which continues to occur intermittently. A majority of this activity originates from vents within the large Otake summit crater. This report updates information during January through June 2020 using monthly reports from the Japan Meteorological Agency (JMA), the Tokyo Volcanic Ash Advisory Center (VAAC), and various satellite data.
During 3-10 January 2020, 13 explosions were detected from the Otake crater rising to 1.4 km altitude; material was ejected as far as 600 m away and ashfall was reported in areas 4 km SSW, according to JMA. Occasional small eruptive events continued during 12-17 January, which resulted in ash plumes that rose 1 km above the crater rim and ashfall was again reported 4 km SSW. Crater incandescence was visible nightly during 17-24 January, while white plumes rose as high as 700 m above the crater rim.
Nightly incandescence during 7-29 February, and 1-6 March, was accompanied by intermittent explosions that produced ash plumes rising up to 1.2 km above the crater rim (figure 44); activity during early February resulted in ashfall 4 km SSW. On 19 February an eruption produced a gray-white ash plume that rose 1.6 km above the crater (figure 45), resulting in ashfall in Toshima village (4 km SSW), according to JMA. Explosive events during 23-24 February ejected blocks onto the flanks. Two explosions were recorded during 1-6 March, which sent ash plumes as high as 900-1,000 m above the crater rim and ejected large blocks 300 m from the crater.
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Figure 44. Surveillance camera images of summit incandescence at Suwanosejima on 29 January (top left), 21 (middle left) and 23 (top right) February, and 25 March (bottom left and right) 2020. Courtesy of JMA (Monthly bulletin reports 511, January, February, and March 2020). |
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Figure 45. Surveillance camera images of which and white-and-gray gas-and-steam emissions rising from Suwanosejima on 5 January (top), 19 February (middle), and 24 March 2020 (bottom). Courtesy of JMA (Monthly bulletin reports 511, January, February, and March 2020). |
Nightly incandescence continued to be visible during 13-31 March, 1-10 and 17-24 April, 1-8, 15-31 May, 1-5 and 12-30 June 2020; activity during the latter part of March was relatively low and consisted of few explosive events. In contrast, incandescence was frequently accompanied by explosions in April and May. On 28 April at 0432 an eruption produced an ash plume that rose 1.6 km above the crater rim and drifted SE and E, and ejected blocks as far as 800 m from the crater. The MODVOLC thermal alerts algorithm also detected four thermal signatures during this eruption within the summit crater. An explosion at 1214 on 29 April caused glass in windows to vibrate up to 4 km SSW away while ash emissions continued to be observed following the explosion the previous day, according to the Tokyo VAAC.
During 1-8 May explosions occurred twice a day, producing ash plumes that rose as high as 1 km above the crater rim and ejecting material 400 m from the crater. An explosion on 29 May at 0210 produced an off-white plume that rose as high as 500 m above the crater rim and ejected large blocks up to 200 m above the rim. On 5 June an explosion produced gray-white plumes rising 1 km above the crater. Small eruptive events continued in late June, producing ash plumes that rose as high as 900 m above the crater rim.
MIROVA (Middle InfraRed Observation of Volcanic Activity) analysis of MODIS satellite data showed relatively stronger thermal anomalies in late February and late April 2020 with an additional six weaker thermal anomalies detected in early January (2), early February (1), mid-April (2), and mid-May (1) (figure 46). Sentinel-2 thermal satellite imagery in late January through mid-April showed two distinct thermal hotspots within the summit crater (figure 47).
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Figure 46. Prominent thermal anomalies at Suwanosejima during July-June 2020 as recorded by the MIROVA system (Log Radiative Power) occurred in late February and late April. Courtesy of MIROVA. |
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Figure 47. Sentinel-2 thermal satellite images showing small thermal anomalies (bright yellow-orange) from two locations within the Otake summit crater at Suwanosejima. Images with “Atmospheric penetration” (bands 12, 11, 8A) rendering; courtesy of Sentinel Hub Playground. |
Information Contacts: Japan Meteorological Agency (JMA), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); Tokyo Volcanic Ash Advisory Center (VAAC), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).
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Explosion rate increases during July-December 2020, bomb ejected 1.3 km from crater on 28 December
Suwanosejima, an andesitic stratovolcano in Japan's northern Ryukyu Islands, was intermittently active for much of the 20th century, producing ash plumes, Strombolian explosions, and ashfall. Continuous activity since October 2004 has included intermittent explosions which generate ash plumes that rise hundreds of meters above the summit to altitudes between 1 and 3 km. Incandescence is often observed at night and ejecta periodically reaches over a kilometer from the summit. Ashfall is usually noted several times each month in the nearby community on the SW flank of the island. Ongoing activity for the second half of 2020, which includes significantly increased activity in December, is covered in this report with information provided by the Japan Meteorological Agency (JMA), the Tokyo Volcanic Ash Advisory Center (VAAC), and several sources of satellite data.
A steady increase in activity was reported during July-December 2020. The number of explosions recorded increased each month from only six during July to 460 during December. The energy of the explosions increased as well; ejecta was reported 600 m from the crater during August, but a large bomb reached 1.3 km from the crater at the end of December. After an increased period of explosions late in December, JMA raised the Alert Level from 2 to 3 on a 5-level scale. The MIROVA graph of thermal activity indicated intermittent anomalies from July through December 2020, with a pulse of activity in the second half of December (figure 48).
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Figure 48. MIROVA thermal activity for Suwanosejima for the period from 3 February through December 2020 shows pulses of activity in February and April, with intermittent anomalies until another period of frequent stronger activity in December. Courtesy of MIROVA. |
Six explosions were recorded during July 2020, compared with only one during June. According to JMA, the tallest plume rose 2,000 m above the crater rim. Incandescent ejecta was occasionally observed at night. The Tokyo VAAC reported a number of ash plumes that rose to 1.2-2.7 km altitude and drifted NW and W during the second half of the month (figure 49). Activity increased during August 2020 when thirteen explosions were reported. The Tokyo VAAC reported a few ash plumes during 1-6 August that rose to 1.8-2.4 km altitude and drifted NW; a larger pulse of activity during 18-22 August produced plumes that rose to altitudes ranging from 1.8 to over 2.7 km. Ashfall was reported on 19 and 20 August in the village located 4 km SSW of the crater; incandescence was visible at the summit and ash plumes drifted SW in satellite imagery on 19 August (figure 50). A MODVOLC thermal alert was issued on 19 August. On 21 August a large bomb was ejected 600 m from the Otake crater in an explosion early in the day; later that afternoon, an ash plume rose to more than 2,000 m above the crater rim. During 19-22 August, SO2 emissions were recorded each day by the TROPOMI instrument on the Sentinel-5P satellite (figure 51).
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Figure 49. An ash emission at Suwanosejima rose to 2.7 km altitude and drifted NW on 27 July 2020. Courtesy of JMA (Volcanic activity commentary material on Suwanosejima, July 2020). |
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Figure 50. Ash drifted SW from the summit crater of Suwanosejima on 19 August 2020 and a bright thermal anomaly was present at the summit. Residents of the village 4 km SW reported ashfall that day and the next. Courtesy of Sentinel Hub Playground. |
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Figure 51. A period of increased activity at Suwanosejima during 19-22 August 2020 produced SO2 emissions that were measured by the TROPOMI instrument on the Sentinel-5P satellite. Nishinoshima, was also producing significant SO2 at the same time. Courtesy of NASA Global Sulfur Dioxide Monitoring Page. |
Thirteen explosions were recorded during September 2020, with the highest ash plumes reaching 2,000 m above the crater rim, and bombs falling 400 m from the crater. Ashfall was recorded on 20 September in the community located 4 km SSW. The Tokyo VAAC reported intermittent ash plumes during the month that rose to 1.2-2.1 km altitude and drifted in several directions. Incandescence was frequently observed at night (figure 52). Explosive activity increased during October with 22 explosions recorded. Ash plumes rose over 2,000 m above the crater rim, and bombs reached 700 m from the crater. Steam plumes rose 2,300 m above the crater rim. Ashfall and loud noises were confirmed several times between 2 and 14 October in the nearby village. A MODVOLC thermal alert was issued on 6 October. The Tokyo VAAC reported multiple ash plumes throughout the month; they usually rose to 1.5-2.1 km altitude and drifted in many directions. The plume on 28 October rose to over 2.7 km altitude and was stationary.
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Figure 52. Incandescence at night and ash emissions were observed multiple times at Suwanosejima during September and October 2020 including on 21 and 26 September (top) and 29 October 2020. Courtesy of JMA (Volcanic activity commentary material on Suwanosejima, September and October 2020). |
Frequent explosions occurred during November 2020, with a sharp increase in the number of explosions to 105 events compared with October. Ash plumes rose to 1,800 m above the crater rim and bombs were ejected 700 m. Occasional ashfall and loud noises were reported from the nearby community throughout the month. Scientists measured no specific changes to the surface temperature around the volcano during an overflight early on 5 November compared with the previous year. At 0818 on 5 November a small ash explosion at the summit crater was photographed by the crew during an observation flight (figure 53). On 12 and 13 November, incandescent ejecta fell 600 m from the crater and ash emissions rose 1,500 m above the crater rim (figure 54).
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Figure 53. A minor explosion produced a small ash plume at Suwanosejima during an overflight by JMA on the morning of 5 November 2020. The thermal activity was concentrated at the base of the explosion (inset). Image taken from off the E coast. Courtesy of JMA (Volcanic activity commentary material on Suwanosejima, November 2020). |
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Figure 54. On 12 and 13 November 2020 incandescent ejecta from Suwanosejima reached 600 m from the crater (top) and ash emissions rose 1,500 m above the crater rim (bottom). Courtesy of JMA (Volcanic activity commentary material on Suwanosejima, November 2020). |
During December 2020 there were 460 explosions reported, a significant increase from the previous months. Ash plumes reached 1,800 m above the summit. Three MODVOLC thermal alerts were issued on 25 December and two were issued the next day. The number of explosions increased substantially at the Otake crater between 21 and 29 December, and early on 28 December a large bomb was ejected to 1.3 km SE of the crater (figure 55). A second explosion a few hours later ejected another bomb 1.1 km SE. An overflight later that day confirmed the explosion, and ash emissions were still visible (figure 56), although cloudy weather prevented views of the crater. Ashfall was noted and loud sounds heard in the nearby village. A summary graph of observations throughout 2020 indicated that activity was high from January through May, quieter during June, and then increased again from July through the end of the year (figure 57).
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Figure 55. Early on 28 December 2020 a large explosion at Suwanosejima sent a volcanic bomb 1.3 km SE from the summit (bright spot on left flank in large photo). Thermal imaging taken the same day showed the heat at the eruption site and multiple fragments of warm ejecta scattered around the crater area (inset). Courtesy of JMA (Volcanic activity commentary material on Suwanosejima, December 2020). |
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Figure 56. Ash emissions were still visible midday on 28 December 2020 at Suwanosejima during a helicopter overflight by the 10th Regional Coast Guard. Image taken from the SW flank of the volcano. Two large explosions earlier in the day had sent ejecta more than a kilometer from the crater. Courtesy of JMA (Volcanic activity commentary material on Suwanosejima, December 2020). |
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Figure 57. Activity summary for Suwanosejima for January-December 2020 when 764 explosions were recorded. Black bars represent the height of steam, gas, or ash plumes in meters above the crater rim, gray volcano icons represent explosions, usually accompanied by an ash plume, red icons represent large explosions with ash plumes, orange diamonds indicate incandescence observed in webcams. Courtesy of JMA (Suwanosejima volcanic activity annual report, 2020). |
Information Contacts: Japan Meteorological Agency (JMA), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground); NASA Global Sulfur Dioxide Monitoring Page, Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center (NASA/GSFC), 8800 Greenbelt Road, Goddard, Maryland, USA (URL: https://so2.gsfc.nasa.gov/).
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Intermittent explosions send incandescent ejecta 1 km from summit during January-June 2021
Suwanosejima, an andesitic stratovolcano in Japan's northern Ryukyu Islands, was intermittently active for much of the 20th century, producing ash plumes, Strombolian explosions, and ashfall. Ongoing activity since October 2004 has included explosions which generate incandescent ejecta and ash plumes that rise hundreds of meters above the summit to altitudes between 1 and 3 km. Incandescence is often observed at night and ejecta periodically reaches as far as a kilometer from the summit. Ashfall is usually noted several times each month in the nearby community on the SW flank of the island. Ongoing activity for January-June 2021 is covered in this report with information provided by the Japan Meteorological Agency (JMA), the Tokyo Volcanic Ash Advisory Center (VAAC), and several sources of satellite data.
Intermittent pulses of explosive activity continued during January-June 2020. Ashfall was reported a few times each month in the village 4 km SW of the summit. Vibrations were felt there during the stronger explosive events, and summit incandescence was frequently observed with the surveillance camera located in the town. Most of the daily multiple explosions reached 1.2-1.8 km altitude and drifted in multiple directions, but several times each month ash emissions reached 2 km altitude or higher. Twice in March and once in June incandescent ejecta reached almost one kilometer from the summit crater, prompting JMA to raise the alert level. The MIROVA Log Radiative Power graph of the MODIS thermal anomaly data through June 2021 indicates intermittent pulses of increased thermal activity in late December 2020, March, and April 2021 that appear to correspond to increased periods of explosive activity (figure 58).
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Figure 58. The MIROVA Log Radiative Power graph of the MODIS thermal anomaly data from 28 October 2020 through June 2021 indicates intermittent pulses of increased thermal activity in late December 2020, March 2021, and April 2021 that appear to correspond to increased periods of explosive activity. Courtesy of MIROVA. |
After a pulse of explosive activity at the end of December 2020, there was a decrease in activity during January 2021. This fact, along with no significant changes in the crustal movement data, led JMA to reduce the Alert Level from 3 (Mountain-entry restrictions) to 2 (Crater-area restrictions) on 14 January. No ejecta had traveled more than 1 km from the crater since late December. Only seven explosions were recorded during January compared with 460 in December 2020. Ash emissions rose up to 2,500 m above the crater rim, and ejecta traveled 400 m from the crater edge. During an overflight on 19 January JMA confirmed gray and white emissions at the summit and noted no particular changes to the crater since the previous observation on 28 December 2020. Numerous small explosions reported by the Tokyo VAAC rose to 1.2-1.8 km altitude and drifted in multiple directions, often S or SE, on most days during the month. During 15-16 January ash plumes rose to 2.0-2.4 km altitude and drifted NE. The highest plumes in January were reported on 20 and 21 January when they rose to 2.4 km and drifted W and E (figure 59).
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Figure 59. Ash emissions at Suwanosejima rose 2.5 km above the summit, according to JMA, on 20 January 2021 (left). The next day, incandescent ejecta traveled 400 m NE of the crater during explosive activity (right). Courtesy of JMA (Volcanic activity commentary for Suwanosejima, January 2021). |
Seven explosions were also recorded during February 2021; they produced ash plumes that rose 1,800 m above the crater rim, and scattered ejecta up to 500 m from the Mitake crater. Ashfall and vibrations were reported several times in the nearby village, and incandescence was sometimes visible at night. From 2-9 February the Tokyo VAAC reported intermittent ash emissions on most days that rose to 1.2-1.8 km altitude and drifted S or SE. On 13 February an ash plume rose to 2.1 km altitude and drifted W. Ash emissions appeared in Sentinel-2 satellite imagery drifting E on 20 February (figure 60). The Tokyo VAAC reported the emissions at 1.2-1.5 km altitude. During 23-26 February ash emissions were reported at 1.5-1.8 km altitude drifting S, SW, NW, and SE.
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Figure 60. Ash emissions were captured drifting E in Sentinel-2 satellite imagery at Suwanosejima on 20 February 2021. Image uses Atmospheric penetration rendering (bands 12, 11, 8a). Courtesy of Sentinel Hub Playground. |
Two periods of increased explosive activity occurred during 2-7 and 30-31 March 2021; the number of explosions increased to 212 from the seven recorded during February. The Tokyo VAAC reported explosions with ash emissions that rose to 1.2-1.5 km altitude and drifted S and W during 1-5 March. Early on 6 March ejecta was thrown 900 m SE from the crater, followed by additional explosions that sent ejecta 400 m (figure 61). Ash plumes rose to 1.8-2.1 km altitude during 6-9 March. An ash emission reached 1,500 m above the crater (2.3 km altitude) on 15 March and an ash plume on 17 March reached 2.4 km altitude and drifted NE. Between 18 March and the end of the month the explosions sent plumes to 1.2-2.1 km altitude in multiple directions. A distinct thermal anomaly was recorded inside the summit crater on 27 March in Sentinel-2 satellite imagery (figure 62), likely from multiple explosions of incandescent ejecta. Large blocks of ejecta traveled up to 1 km multiple times during 30-31 March, resulting in JMA raising the Alert Level from 2 to 3 (on a scale of 1-5). In addition, ash emissions rose 800 m high with the explosions. During an overflight on 31 March JMA noted ash emissions (figure 63) and multiple high temperatures areas around the crater interpreted to be from incandescent ejecta. Vibrations were felt in the nearby village on both 6 and 31 March, and ashfall was reported several times.
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Figure 61. Incandescent ejecta and ash emissions increased significantly during March 2021 at Suwanosejima. Ejecta was thrown 900 m SE from the summit on 6 March; note the bright spot to the left of summit. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, March 2021). |
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Figure 62. A bright thermal anomaly and ash plume drifting NW were recorded in Sentinel-2 satellite imagery at Suwanosejima on 27 March 2021. Image uses Atmospheric penetration rendering (bands 12, 11, 8a). Courtesy of Sentinel Hub Playground. |
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Figure 63. Gray ash emissions were visible at the Mitake Crater of Suwanosejima during an overflight by JMA on 31 March 2021; view is from the SSE flank. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, March 2021). |
A decrease in activity in early April 2021 led JMA to reduce the Alert Level from 3 to 2 on 5 April; 64 explosions were reported for the month. Incandescent ejecta reached 600 m from the crater. Ashfall was occasionally reported at the village 4 km away, and summit incandescence was occasionally observed from there as well. The Tokyo VAAC reported explosions on 1 and 2 April, and then multiple explosions daily during 6-12 April with ash plumes that rose to 1.5-2.7 km altitude and drifted SW and W. Multiple daily explosions continued during 19-21 and 23-30 April, with most plumes rising to 1.5-1.8 km altitude and drifting W or SW. Emissions reached 2.4 km altitude on 28 April and drifted NE and N. A very small thermal anomaly inside the summit crater was recorded in Sentinel-2 imagery on 21 April.
One hundred explosions were reported by JMA during May 2021. Incandescent ejecta reached 700 m from the crater rim on 6 May. Ashfall was recorded and vibrations were felt a number of times in the village 4 km SSW along with occasional incandescence visible at the summit crater with the surveillance camera located in the village. Higher altitude ash plumes were observed in May than during previous months; plumes reached heights over 2 km above the summit crater at least 13 times. The highest plume, on 30 May, reached 2.6 km above the summit (3.4 km altitude). The Tokyo VAAC reported multiple explosions almost every day of the month; on several days more than five explosions occurred. While the ash plumes often rose to 1.2-1.8 km altitude, they were significantly higher a number of times. During 2-3 May they rose to 2.4-3.0 km altitude and drifted SE and S. During 5-7 and 9-13 May they rose over 2 km each day. On 17 May a pilot reported ash 185 km SSW at 3.7 km altitude. Additional explosions that rose to over 2 km altitude occurred on 21-23 and 26-31 May. Plumes rose to 3.0-3.4 km altitude on 30 May and ten explosions were recorded the next day rising to 1.2-2.4 km altitude. One of them was recorded in Sentinel-2 satellite imagery (figure 64).
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Figure 64. A dense ash emission drifted W from Suwanosejima on 31 May 2021 as seen in Sentinel-2 satellite imagery with Atmospheric penetration rendering (bands 12, 11, 8a). Courtesy of Sentinel Hub Playground. |
Ash emissions during June 2021 rose as high as 2,400 m above the crater; there were 157 explosions reported. Larger explosions on 21 and 23 June resulted in incandescent ejecta being thrown about 900 m NW and SE from the crater (figure 65). This prompted JMA to raise the Alert Level on 23 June from 2 to 3. The Japan Meteorological Agency Mobile Survey Team (JMA-MOT) conducted an aerial observation that day and confirmed that a part of the floor of the Mitake crater was still incandescent (figure 66); in addition, thermal anomalies were measured from scattered ejecta around the crater. The Tokyo VAAC reported multiple daily explosions and ash plumes throughout the month, most of which rose to 1.2-2.1 km altitude and drifted in various directions. Nine explosions were recorded on 1 June with plumes that rose as high as 2.4 km altitude and drifted W. Reports of plumes visible at 3.0 km altitude were noted on 1 and 2 June. During 4-9 June the multiple daily explosions rose to 1.2-2.1 km altitude drifting SE and NE; they were higher on 8 June, rising to 2.4-3.0 km altitude and drifting NW. Explosions on 14 June rose to 2.4 km altitude, and on 23 June ten explosions were recorded; two of them reached 3.0 km altitude and drifted SW. For the remainder of June, most days included explosions over 2 km altitude.
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Figure 65. Large blocks of incandescent ejecta were sent about 900 m NW and SW from the Mitake crater at Suwanosejima on 21 June 2021. Note the bright spots both to the left and right of the summit. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, June 2021). |
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Figure 66. An aerial observation flight by JMA on 23 June 2021 at Suwanosejima confirmed the presence of incandescent ejecta inside the summit crater. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, June 2021). |
Information Contacts: Japan Meteorological Agency (JMA), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground);
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Frequent explosions with ash plumes and ejecta
Suwanosejima is an 8-km-long island located in the northern Ryukyu Islands, Japan, consisting of a stratovolcano and two historically active summit craters. Volcanism was intermittent for much of the 20th century, characterized by Strombolian explosions, ash plumes, and ashfall. The current eruption began in October 2004 and has recently consisted of intermittent explosions, ash emissions, and incandescent ejecta (BGVN 46:09). Incandescence is often observed at night and ejecta periodically reaches as far as a kilometer from the summit. Ashfall is usually noted several times each month in the nearby community on the SW flank of the island. This report covers activity from July 2021 through March 2022 using information from the Japan Meteorological Agency (JMA), the Tokyo Volcanic Ash Advisory Center (VAAC), and several sources of satellite data.
Intermittent explosions were detected in the Otake crater, generating ash plumes that rose 5.4 km above the crater rim. Larger volcanic bombs were ejected as far as 1.9 km from the crater. Crater incandescence was frequently visible at night. The MIROVA Log Radiative Power graph of the MODIS thermal anomaly data through March 2022 indicates intermittent pulses of increased thermal activity in in late April to early May 2021, July 2021, September 2021, two small pulses in early and late November 2021, and early January 2022 that appear to correspond to increased periods of explosive activity (figure 67). According to data from the MODVOLC thermal algorithm, a total of eight hotspots were detected: one on 29 August, one on 10 September, two on 21 September, one on 23 September 2021, one on 4 January 2022, and two on 6 January. Reports of eruption sounds were heard in Toshima village (4 km SSW), in addition to occasional ashfall events.
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Figure 67. The MIROVA Log Radiative Power graph of the MODIS thermal anomaly data from 4 April 2021 through March 2022 indicates intermittent pulses of increased thermal activity in late April to early May 2021, July 2021, September 2021, two small pulses in early and late November 2021, and early January 2022 that appear to correspond to increased periods of explosive activity. Courtesy of MIROVA. |
Ongoing explosions during July generated ash plumes that rose 1.6-3.6 km high (figure 68). Bombs were ejected as far as 1 km from the crater, accompanied by occasional crater incandescence that was visible at night. An explosion on 8 July at 0439 ejected bombs 800 m NW. An explosion at 1319 on 12 July generated an ash plume that rose 3 km high and later at 2330 a second explosion produced an ash plume 3.6 km high. Eruption sounds were heard in Toshima village; ashfall deposits were reported in the village during 12-19 July. On 29 July JMA lowered the Volcano Alert Level to 2 (on a 5-level scale) at 1100 and warned the public to stay 1 km from the crater.
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Figure 68. Photo of an eruption plume rising 3.8 km high above Suwanosejima at 1814 on 31 July 2021. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, July 2021). |
During August, explosions continued, producing ash plumes that rose 2.2-4.8 km high. Large blocks were ejected as far as 500 m from the crater, accompanied by nightly crater incandescence. Ashfall was occasionally reported in Toshima village. On 19 August an explosion at 0137 and 1613 produced an ash plume that rose 3 km and 2.2 km NE and N above the crater, respectively. A third explosion at 2059 generated an ash plume that rose 2.5 km above the crater and drifted N. A small amount of ashfall was reported in Yakushima, Nishinoomote, and Nakatane, as well as Toshima village. Explosions at 0628 and 0713 on 20 August produced ash plumes that rose 2.5-3 km above the crater and drifted N, resulting in ashfall in Toshima village, with smaller amounts in Yakushima, Mishima, Ibusuki, Minamikyushu, and Makurazaki. An explosion at 0617 on 21 August resulted in an ash plume 3.2 km above the crater that drifted N; a large amount of ash (over 1 mm) was detected in Toshima village and a smaller amount (less than 0.1 mm) was detected in Makurazaki, Minamisatsuma, Minamikyushu, Kagoshima, Ibusuki, and Hioki. A second explosion that day at 0906 produced an ash plume up to 3.2 km high that drifted N. On 28 August an explosion occurred at 1231 that produced an ash plume 4.8 km above the crater, though weather clouds prevented clear views of the summit.
Explosions persisted during September, with ash plumes rising 2.4-5.4 km high. Some crater incandescence was visible at night, which was also detected in Sentinel-2 infrared satellite imagery on clear weather days (figure 69). On 17 September explosions were detected at 0212 and 0218, which ejected material 1 km SE from the crater. JMA raised the Alert Level to 3 at 0235. On 20 September an explosion ejected material as far as 1.2 km SE from the crater. An eruptive event at 0711 on 26 September produced an ash plume that rose 5.4 km high, though weather clouds prevented a clear view of the summit. As a result, ejecta traveled 800 m from the crater and a large amount of ash was reported in Toshima village.
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Figure 69. A thermal anomaly (bright yellow-orange) and occasional gray ash plumes were recorded in Sentinel-2 satellite imagery at Suwanosejima on 23 September (top left), 28 October (top right) 2021, 26 January (bottom left), and 12 March (bottom right) 2022. The size of the hotspot visibly decreased during 2022. Image uses Atmospheric penetration rendering (bands 12, 11, 8a). Courtesy of Sentinel Hub Playground. |
During October, frequent explosions continued, generating ash plumes up to 3.3 km high and ejecting bombs as far as 1.1 km from the crater. Occasional crater incandescence was noted at night, as well as ashfall in Toshima village. On 26 October an explosion at 1317 produced an ash plume that rose 3.3 km above the crater and ejected material was reported up to 1.9 km from the crater (figure 70). Similar activity continued in November with explosions that produced ash plumes 1.2-2.7 km above the crater. Large volcanic bombs were ejected 800 m from the crater and occasional ashfall was reported in Toshima village. During late November crater incandescence was visible nightly.
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Figure 70. Photo of an eruption plume rising 3.3 km above Suwanosejima at 1317 on 26 October 2021. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, October 2021). |
Explosions during December generated ash plumes 1.5-3.1 km high and ejected large blocks as far as 800 m from the crater. Some ash plumes rose 1-3.4 km high in early December but were not associated with explosive events. Occasional crater incandescence was visible at night. Hundreds of explosions persisted during January 2022 with ash plumes rising 1.4-3 km high and nighttime crater incandescence. Material was ejected 1.1 km from the crater. During the latter half of the month, rumbling sounds and ashfall were reported in Toshima village.
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Figure 71. Photo of crater incandescence from Suwanosejima at 0106 on 9 January 2022. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, January 2022). |
Similar activity continued during February and March with intermittent explosions and ash plumes rising 1.3-2.8 km high. Bombs were ejected 900 m from the crater and crater incandescence persisted. Ashfall also was also intermittently reported in Toshima village.
Information Contacts: Japan Meteorological Agency (JMA), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).
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Intermittent explosions, eruption plumes, ashfall, and incandescent ejecta during April-December 2022
Suwanosejima, located in the northern Ryukyu Islands, Japan, is an 8-km-long island that consists of a stratovolcano and two historically active summit craters. Volcanism was intermittent for much of the 20th century, characterized by Strombolian explosions, ash plumes, and ashfall. The current eruption began in October 2004 and has recently consisted of frequent explosions, ash plumes, thermal activity, and ashfall (BGVN 47:04). This report updates similar activity of explosions, eruption plumes, ashfall, thermal activity, and seismicity during April-December 2022 based on information from the Japan Meteorological Agency (JMA) and satellite data.
Intermittent explosions were reported in the Otake crater, producing volcanic plumes that rose as high as 3.3 km above the crater rim, which occasionally resulted in ashfall in the nearby Toshima village (3.5 km SSW). Large volcanic blocks were ejected 900 m from the crater center and nighttime crater incandescence was frequently reported. Two thermal hotspots were detected by the MODVOLC thermal alerts system on the NW and NE flanks on 19 October 2022. The MIROVA (Middle InfraRed Observation of Volcanic Activity) Log Radiative Power graph of the MODIS thermal anomaly data showed three brief periods of thermal activity during early July, mid-August, and late September through October (figure 72). Sentinel-2 infrared satellite imagery showed three clear weather days with a thermal anomaly during the reporting period on 28 September, 8 October, and 27 November (figure 73).
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Figure 72. Low thermal activity was detected at Suwanosejima briefly in early July, mid-August, and late September through October 2022, according to this MIROVA graph (Log Radiative Power). Courtesy of MIROVA. |
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Figure 73. Sentinel-2 infrared satellite images showed a gray ash emission rising above Suwanosejima on 16 April 2022 (top left), and a thermal anomaly was visible on 28 September (top right), 8 October (bottom left), and 27 November 2022 (bottom right). Images use “Atmospheric penetration” rendering (bands 12, 11, 8a). Courtesy of Sentinel Hub Playground. |
Eruptive activity in the Otake crater continued during April; about 123 explosions were detected during the first half of the month. Crater incandescence was visible each night during 1-5 April. The sounds of rumbling and ashfall were occasionally reported in Toshima village, as well as sometimes in areas up to 5 km from the crater. Seismicity consisted of 491 volcanic earthquakes, not including explosion-related earthquakes. An explosion on 4 April at 2241 generated an eruption plume that rose 3.3 km above the crater rim. Large volcanic blocks were ejected as far as 900 m SE from the crater. No eruptive activity was reported during 9-11 and 15-18 April, although emissions rose 700-1,100 m above the crater rim. According to observations conducted by the University of Tokyo, Kyoto University, Toshima village, and JMA, the amount of sulfur dioxide released ranged from 300 to 1,600 tons per day (t/d), which was lower compared to March (3,400 t/d).
One explosion was detected during early May, followed by three more during 20-23 May; there were 33 explosions reported after 22 May through the end of the month. An explosion on 28 May at 0327 produced an eruption plume that rose 1.9 km above the crater rim. Large volcanic blocks were ejected about 500 m S from the crater. Nighttime incandescence was intermittently captured with a high-sensitivity surveillance camera. Rumbling sounds and ashfall were occasionally reported in Toshima village. A total of 417 volcanic earthquakes were detected during the month. Sulfur dioxide emissions had increased slightly compared to April, with 1,200-2,000 t/d emitted.
According to JMA, the number of explosions had decreased after April; there were 21 explosions that were detected dominantly during 2-6 and 30 June. The explosions ejected large volcanic blocks as far as 600 m S from the crater. On 7 June ashfall was observed in Toshima village. During 10-13 June eruption plumes rose as high as 1.5 km above the crater rim and ejected material as far as 300 m from the vent. On 26 June at 1418 an explosion generated an eruption plume that rose 2 km above the crater rim. Nighttime crater incandescence continued. There were 314 volcanic earthquakes detected throughout the month. The amount of sulfur dioxide emissions ranged between 1,000 t/d and 3,700 t/d.
Since mid-April, eruptive activity continued to decrease and as a result, JMA lowered the Volcano Alert Level (VAL) to 2 (on a 5-level scale) on 11 July. The number and intensity of explosions had been variable since early April, but showed an overall decline, and material had not been ejected more than 1 km. Eruption plume heights occasionally exceeded 3 km above the crater rim since July 2021, but these heights had not been observed since mid-April 2022. The number of volcanic earthquakes temporarily increased on 17 May but were generally low. The number of recorded explosions during July was 34 and large volcanic blocks accompanied by explosions were ejected as far as 700 m SW from the crater. Nighttime crater incandescence persisted during both July and August. On 26 July at 2351 a volcanic plume rose more than 1.8 km above the crater rim. Resulting ashfall was reported in Toshima village. The number of volcanic earthquakes detected in the vicinity increased to 526 compared to the previous months. Sulfur dioxide measurements showed that 700-2,500 t/d were released during July and 600-2,200 t/d during August.
Beginning on 2 August, the number of explosions increased; there were 24 explosions detected during 2-7 August. On 11 and 28 August explosions at 0416 and 2151, respectively, ejected large blocks 800 m from the vent. Eruption plumes during 7-8 August rose 2 km above the crater and mixed with weather clouds (figure 74). During 28-29 August three explosions generated ash plumes that rose as high as 1.3 km above the crater rim. Intermittent explosions occurred during August (51 total) and the number of volcanic earthquakes increased to 615.
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Figure 74. Webcam image showing an eruption plume rising 2 km above the crater rim of Suwanosejima at 2340 on 8 August 2022. Photo has been color corrected. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, August 2022). |
During September, 88 explosions were recorded; 25 occurred during 24-28 September. The frequency of explosions was greater in September than August. Thermal activity continued to be reported during the night, based on high-sensitivity surveillance cameras. Occasional rumbling sounds and ashfall were observed as well. On 24 September at 1819 an eruption plume rose more than 2 km above the crater rim. An aerial survey was conducted by the Japan Meteorological Agency Mobile Research Team (JMA-MOT) on 29 September in cooperation with the Kagoshima Prefecture reported that a gray-white plume was observed rising above the Mitake crater (figure 75). Additionally, observations made using an infrared thermal imaging device confirmed high temperature areas near the summit, which were interpreted to be the scattered ejecta around the crater. The VAL was raised to 3 (on a 5-level scale) on 28 September. On 30 September at 2141 an explosion ejected large volcanic blocks 900 m S from the crater. The number of volcanic earthquakes around the volcano increased significantly to 1,351 and sulfur dioxide emissions ranged between 500-1,600 t/d.
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Figure 75. A gray-white plume was visible during an aerial survey of Suwanosejima at the Mitake crater at 1502 on 29 September 2022 (left). Higher temperature (red color is higher in temperature) areas based on an image from an infrared thermal imaging device was reported to be incandescent volcanic blocks (right). Photo on the left has been color corrected. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, September 2022). |
The number of detected explosions continued to increase during October, particularly with 119 detected during 17-19 October, and a total of 244 recorded through the month. An eruption at 1342 on 8 October produced a volcanic plume that rose 2.4 km above the crater rim. An aerial survey was conducted on 11 October in cooperation with the Kagoshima Prefecture and reported that gray-white plumes continued to rise above the Mitake crater. An explosion at 0513 on 20 October ejected large volcanic blocks to 800 m SW from the crater. Nighttime crater incandescence continued, in addition to occasional rumbling sounds and ashfall in Toshima village. There was an increase in the number of volcanic earthquakes during 25-31 October, with a total of 2,034 events detected. Sulfur dioxide emissions measured between 400 and 2,100 t/d; there were multiple days in which the amount of sulfur dioxide emissions exceeded 2,000 t/d, according to JMA.
Eruptive activity during November and December had notably decreased; 3 explosions were detected. Nighttime crater incandescence persisted, as well as occasional rumbling sounds and ashfall in Toshima village. There were 465 volcanic earthquakes detected during the month. On 4 November at 0137 a volcanic plume rose 2.4 km above the crater rim. An explosion was detected at 2238 on 11 November that generated an eruption plume that rose 1.6 km above the crater rim. An explosion at 0251 on 15 November produced volcanic plumes that rose 1-1.3 km above the crater rim and drifted SE; associated large volcanic blocks were ejected 500 m S from the crater. JMA reported that 700-2,000 t/d of sulfur dioxide emissions were measured during November. During December, activity remained relatively low compared to previous months; no explosions were observed during the month, though nighttime crater incandescence remained visible, according to JMA. Ashfall was occasionally reported in Toshima village. There were 184 volcanic earthquakes detected during the month. An eruption at 0421 on 2 December ejected material as far as 300 m E of the crater. An eruption plume on 3 December rose more than 1.8 km above the crater. Approximately 400-800 t/d sulfur dioxide emissions were measured, which was lower compared to November.
Information Contacts: Japan Meteorological Agency (JMA), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground).
Cite this Report
Frequent eruption plumes, explosions, and incandescent ejecta during January-June 2023
Suwanosejima is located in the northern Ryukyu Islands, Japan, and is an 8-km-long island that consists of a stratovolcano and two active summit craters. Volcanism during the 20th century is characterized by Strombolian explosions, ash plumes, and ashfall. The current eruption began in October 2004 and has more recently consisted of intermittent explosions, eruption plumes, ashfall, and incandescent ejecta (BGVN 48:01). Similar activity continued during this reporting period of January through June 2023, based on monthly report from the Japan Meteorological Agency (JMA) and satellite data.
The MIROVA (Middle InfraRed Observation of Volcanic Activity) Log Radiative Power graph of the MODIS thermal anomaly data showed low thermal activity throughout the reporting period (figure 76). Three anomalies were detected during February, four during March, three during April, one during late May, and two during early June. A single thermal hotspot was detected by the MODVOLC thermal alerts system on the NE flank on 7 February. There were only two clear weather days in infrared satellite imagery that showed a thermal anomaly on 7 March and 5 June (figure 77).
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Figure 76. Low thermal activity was detected at Suwanosejima during January through June 2023, based on this MIROVA graph (Log Radiative Power). Three anomalies were detected during February, four during March, three during April, one during late May, and two during early June. Courtesy of MIROVA. |
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Figure 77. Infrared (bands B12, B11, B4) satellite imagery showing two thermal anomalies at the Otake crater of Suwanosejima on 7 March 2023 (left) and 5 June 2023 (right). Courtesy of Copernicus Browser. |
Activity in the Otake crater during January 2023 was relatively low, which prompted JMA to lower the Volcano Alert Level (VAL) from 3 to 2 (on a 5-level scale) on 24 January. The number of explosions recorded during the month was 13. There were 50 volcanic earthquakes detected on the W side of the island, which was roughly comparable to December (44), although near the Otake crater, there were 188 earthquakes recorded, which excluded earthquakes associated with explosions. An aerial overflight conducted on 11 January by the Japan Maritime Self-Defense Force Air Group (JMSDF) reported a gray-white plume rising from the Otake crater. During 26-30 January there was a brief increase in the number of explosions. An eruption at 0331 on 26 January generated an eruption plume that rose 1.7 km above the crater rim and ejected large blocks 400 m S from the crater. Nighttime crater incandescence was visible in a highly sensitive surveillance camera starting on 26 January. According to the Toshima Village Office, Suwanosejima Branch Office, ashfall was occasionally observed in the village (3.5 km SSW). According to observations conducted by the University of Tokyo Graduate School of Science, Kyoto University Disaster Prevention Research Institute, Toshima Village, and JMA, the amount of sulfur dioxide emissions released during the month was 200-600 tons per day (t/d).
Eruptive activity in the Otake crater continued during February; the total number of explosions increased during this month from 13 to 56. There were 119 volcanic earthquakes detected on the W side of the island and 449 near the Otake crater, excluding earthquakes associated with explosions. During 15-21 February there was a brief increase in the number of explosions, and large blocks were ejected as far as 1 km from the crater. An explosion at 2131 on 15 March ejected material 900 m SE (figure 78). Eruptions on 18 and 27 February generated plumes that rose 2 km above the crater (figure 79). By 21 February the number of explosions reached 42, though no large-scale volcanic earthquakes were reported. Nighttime crater incandescence continued from late January through February. Ashfall was also occasionally observed in Toshima Village. The amount of sulfur dioxide emissions released during the month was 700 t/d.
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Figure 78. Webcam image of the explosion at Suwanosejima’s Otake crater at 2131 on 15 February 2023. Crater incandescence was visible, and large blocks were ejected 900 m from the crater (white dashed line). Courtesy of JMA (Volcanic activity commentary for Suwanosejima, February 2023). |
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Figure 79. Webcam image of the explosion at Suwanosejima’s Otake crater at 1606 on 18 February 2023. The eruption plume rose 2 km above the crater rim. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, February 2023). |
The number of explosions at the Otake crater increased during 2-5 March; 28 explosions were detected during this time. Large volcanic blocks were ejected 500 m from the crater. As a result, the VAL was increased to 3 on 5 March. There were 65 explosions recorded throughout the month. On the W side of the island, 63 volcanic earthquakes were reported, and closer to the Otake crater, 422 were detected, excluding earthquakes associated with explosions. Nighttime crater incandescence continued, as well as occasional ashfall in Toshima Village. On 16 March an eruption produced a volcanic plume that rose 2.4 km above the crater rim (figure 80). The amount of sulfur dioxide emissions released during the month was 200-1,100 t/d.
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Figure 80. Webcam image of an eruption plume rising 2.4 km above the Otake crater at Suwanosejima at 0644 on 16 March 2023. Photo has been color corrected. Courtesy of JMA (Volcanic activity commentary for Suwanosejima, March 2023). |
Eruptive activity continued at the Otake crater during April. Eruption plumes rose as high as 2 km above the crater rim and large blocks were ejected as far as 500 m from the crater. The number of explosions decreased to one throughout the month, although nighttime crater incandescence remained visible in the surveillance camera. Rumbling and ashfall continued intermittently in Toshima Village. There were 32 volcanic earthquakes detected, and 129 volcanic earthquakes near the Otake crater, not including those associated with explosions. According to JMA, the amount of sulfur dioxide released during the month was 200-1,400 t/d. On 16 April at 0402 an eruption ejected incandescent material 500 m S from the crater.
Activity continued at the Otake crater in May. An eruption plume rose 1.8 km above the crater rim and large volcanic blocks were ejected 300 m from the crater. The number of explosions remained low throughout the month (7) and nighttime crater incandescence persisted. Occasional ashfall was reported in Toshima Village. As many as 44 volcanic earthquakes were recorded on the W side of the island, and 205 were recorded closer to the Otake crater, which was higher compared to the previous month. Generally, the amount of sulfur dioxide released during the month ranged 400-700 t/d, but on 19 May the amount increased to 2,600 t/d. On 16 May an eruption produced a volcanic plume that rose 1.8 km above the crater rim.
Eruptive activity was relatively low in June; the number of explosions generally decreased and on 9 June the VAL was lowered to 2. Nighttime crater incandescence continued, and according to the Toshima Village Office, rumbling and ashfall were also noted occasionally. There were 31 explosions throughout the month and 28 volcanic earthquakes detected on the W side of the island and as many as 722 volcanic earthquakes were recorded near the Otake crater. During 13-19 June, JMA reported a brief increase in the number of explosions. On 15 June at 2200 an eruption generated a volcanic plume that rose 2 km above the crater rim. An eruption on 16 June at 2147 ejected material 400 m SE from the crater. The amount of sulfur dioxide emitted was relatively low, at 100 t/d on 27 June.
Information Contacts: Japan Meteorological Agency (JMA), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Copernicus Browser, Copernicus Data Space Ecosystem, European Space Agency (URL: https://dataspace.copernicus.eu/browser/).
This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.
Synonyms |
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| Suwanose-zima | Moe-shima | Suwanose-jima | ||||
Cones |
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| Feature Name | Feature Type | Elevation | Latitude | Longitude |
| Makko-dai | Stratovolcano | |||
|
Nabedao
Negami-dake |
Stratovolcano | 409 m | ||
|
Otake
Ontake Mitake |
Stratovolcano | 796 m | 29° 38' 18" N | 129° 42' 50" E |
| Susaki | Cone | |||
| Suwanosejima Oki | Submarine cone | 29° 38' 30" N | 129° 50' 0" E | |
|
Tondachi
Tondati |
Cone | 536 m | ||
Craters |
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| Feature Name | Feature Type | Elevation | Latitude | Longitude |
| Sakuchi | Caldera | |||
| Tongama | Crater | |||
|
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There is data available for 24 confirmed Holocene eruptive periods.
2004 Oct 23 - 2024 Oct 17 (continuing) Confirmed Eruption VEI: 2
| Episode 1 | Eruption | O-take | ||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2004 Oct 23 - 2024 Oct 17 (continuing) | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||
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List of 5 Events for Episode 1 at O-take
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2000 Dec 19 - 2004 Jul 5 (?) Confirmed Eruption VEI: 3 (?)
| Episode 1 | Eruption | O-take (Upper NE flank) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2000 Dec 19 - 2004 Jul 5 (?) | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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List of 11 Events for Episode 1 at O-take (Upper NE flank)
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2000 Feb 24 ± 4 days - 2000 Feb 24 ± 4 days Confirmed Eruption VEI: 2 (?)
| Episode 1 | Eruption | O-take | |||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2000 Feb 24 ± 4 days - 2000 Feb 24 ± 4 days | Evidence from Observations: Reported | |||||||||||||||||||||||||||||||||||||||||||||||||
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List of 8 Events for Episode 1 at O-take
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1999 Jun 15 ± 5 days - 1999 Jun 30 ± 4 days Confirmed Eruption VEI: 1 (?)
| Episode 1 | Eruption | O-take | ||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1999 Jun 15 ± 5 days - 1999 Jun 30 ± 4 days | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||||||||||||
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List of 7 Events for Episode 1 at O-take
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1999 Jan 5 ± 5 days - 1999 Feb 24 ± 4 days Confirmed Eruption VEI: 1 (?)
| Episode 1 | Eruption | O-take | |||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1999 Jan 5 ± 5 days - 1999 Feb 24 ± 4 days | Evidence from Observations: Reported | |||||||||||||||||||||||||||||||||||||||||||||||||
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List of 8 Events for Episode 1 at O-take
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1996 Dec 26 - 1997 Apr 17 Confirmed Eruption VEI: 1
| Episode 1 | Eruption | O-take | ||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1996 Dec 26 - 1997 Apr 17 | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||
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List of 5 Events for Episode 1 at O-take
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1990 Apr 16 ± 15 days - 1996 Jul 14 Confirmed Eruption VEI: 2
| Episode 1 | Eruption | O-take | |||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1990 Apr 16 ± 15 days - 1996 Jul 14 | Evidence from Observations: Reported | |||||||||||||||||||||||||||||||||||||||
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List of 6 Events for Episode 1 at O-take
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1988 Jan 16 ± 15 days - 1989 Dec 16 ± 15 days Confirmed Eruption VEI: 2
| Episode 1 | Eruption | O-take | |||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1988 Jan 16 ± 15 days - 1989 Dec 16 ± 15 days | Evidence from Observations: Reported | |||||||||||||||||||||||||||||
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List of 4 Events for Episode 1 at O-take
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1985 Sep 16 ± 15 days - 1987 Jun 16 ± 15 days Confirmed Eruption VEI: 2
| Episode 1 | Eruption | O-take | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1985 Sep 16 ± 15 days - 1987 Jun 16 ± 15 days | Evidence from Observations: Reported | ||||||||||||||||||||||||
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List of 3 Events for Episode 1 at O-take
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1984 Oct 16 ± 15 days - 1984 Oct 16 ± 15 days Confirmed Eruption VEI: 2
| Episode 1 | Eruption | O-take | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1984 Oct 16 ± 15 days - 1984 Oct 16 ± 15 days | Evidence from Observations: Reported | ||||||||||||||||||||||||
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List of 3 Events for Episode 1 at O-take
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1960 Jul 2 (?) ± 182 days Confirmed Eruption VEI: 0
| Episode 1 | Eruption | Submarine E flank (Suwanose-jima Oki) | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1960 Jul 2 (?) ± 182 days - Unknown | Evidence from Observations: Reported | ||||||||||||||
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List of 1 Events for Episode 1 at Submarine E flank (Suwanose-jima Oki)
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1956 Nov 16 ± 15 days - 1984 May 16 ± 15 days Confirmed Eruption VEI: 2
| Episode 1 | Eruption | O-take | ||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1956 Nov 16 ± 15 days - 1984 May 16 ± 15 days | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||||||||||||
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List of 7 Events for Episode 1 at O-take
| |||||||||||||||||||||||||||||||||||||||||||||
1954 Jul 2 (?) ± 182 days Confirmed Eruption VEI: 0
| Episode 1 | Eruption | Submarine E flank (Suwanose-jima Oki) | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1954 Jul 2 (?) ± 182 days - Unknown | Evidence from Observations: Reported | ||||||||||||||
|
List of 1 Events for Episode 1 at Submarine E flank (Suwanose-jima Oki)
| |||||||||||||||
1949 Oct - 1954 Jul 2 ± 182 days Confirmed Eruption VEI: 2
| Episode 1 | Eruption | O-take | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1949 Oct - 1954 Jul 2 ± 182 days | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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List of 9 Events for Episode 1 at O-take
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||
1940 Nov 29 Confirmed Eruption VEI: 2 (?)
| Episode 1 | Eruption | O-take | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1940 Nov 29 - Unknown | Evidence from Observations: Reported | |||||||||||||||||||
|
List of 2 Events for Episode 1 at O-take
| ||||||||||||||||||||
1938 Mar 11 - 1938 Mar 11 Confirmed Eruption VEI: 2 (?)
| Episode 1 | Eruption | O-take | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1938 Mar 11 - 1938 Mar 11 | Evidence from Observations: Reported | |||||||||||||||||||
|
List of 2 Events for Episode 1 at O-take
| ||||||||||||||||||||
[ 1934 Jan 11 ] Uncertain Eruption
| Episode 1 | Eruption | O-take | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1934 Jan 11 - Unknown | Evidence from Unknown | |||||||||||||||||||
|
List of 2 Events for Episode 1 at O-take
| ||||||||||||||||||||
1925 May 13 Confirmed Eruption VEI: 2 (?)
| Episode 1 | Eruption | O-take | |||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1925 May 13 - Unknown | Evidence from Observations: Reported | |||||||||||||||||||||||||||||||||||||||||||||||||
|
List of 8 Events for Episode 1 at O-take
| ||||||||||||||||||||||||||||||||||||||||||||||||||
1921 Dec 8 - 1922 Jan 26 Confirmed Eruption VEI: 2 (?)
| Episode 1 | Eruption | O-take | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1921 Dec 8 - 1922 Jan 26 | Evidence from Observations: Reported | |||||||||||||||||||
|
List of 2 Events for Episode 1 at O-take
| ||||||||||||||||||||
[ 1915 Jul - 1915 Sep ] Uncertain Eruption
| Episode 1 | Eruption | O-take | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1915 Jul - 1915 Sep | Evidence from Unknown | |||||||||||||||||||
|
List of 2 Events for Episode 1 at O-take
| ||||||||||||||||||||
[ 1914 Mar 21 ] Uncertain Eruption
| Episode 1 | Eruption | O-take | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1914 Mar 21 - Unknown | Evidence from Unknown | |||||||||||||||||||
|
List of 2 Events for Episode 1 at O-take
| ||||||||||||||||||||
1889 Oct 2 - 1889 Oct 13 Confirmed Eruption VEI: 4
| Episode 1 | Eruption | O-take | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1889 Oct 2 - 1889 Oct 13 | Evidence from Observations: Reported | ||||||||||||||||||||||||
|
List of 3 Events for Episode 1 at O-take
| |||||||||||||||||||||||||
1885 Jan - 1885 May Confirmed Eruption VEI: 2 (?)
| Episode 1 | Eruption | O-take | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1885 Jan - 1885 May | Evidence from Observations: Reported | |||||||||||||||||||
|
List of 2 Events for Episode 1 at O-take
| ||||||||||||||||||||
1884 Confirmed Eruption VEI: 1
| Episode 1 | Eruption | Northeastern summit crater (O-take) | ||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1884 - Unknown | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||
|
List of 5 Events for Episode 1 at Northeastern summit crater (O-take)
| |||||||||||||||||||||||||||||||||||
1877 Confirmed Eruption VEI: 4 (?)
| Episode 1 | Eruption | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1877 - Unknown | Evidence from Observations: Reported | |||||||||||||||||||
|
List of 2 Events for Episode 1
| ||||||||||||||||||||
1813 - 1814 Confirmed Eruption VEI: 4
| Episode 1 | Eruption | SW ridge fissure and O-take | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1813 - 1814 | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
List of 15 Events for Episode 1 at SW ridge fissure and O-take
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1600 (?) Confirmed Eruption VEI: 4
| Episode 1 | Eruption | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1600 (?) - Unknown | Evidence from Correlation: Tephrochronology | |||||||||||||||||||
|
List of 2 Events for Episode 1
| ||||||||||||||||||||
There is data available for 1 deformation periods. Expand each entry for additional details.
| Start Date: 2003 Nov 02 | Stop Date: 2003 Nov 02 | Direction: Variable (uplift / subsidence) | Method: Seismometer |
| Magnitude: Unknown | Spatial Extent: Unknown | Latitude: Unknown | Longitude: Unknown |
Remarks: Vertical displacement seismograms show uplift 100 seconds before an explosive eruption, followed by subsidence during the eruption. | |||
Reference List: Iguchi et al. 2008.
Full References:
Iguchi M, Yakiwara H, Tameguri T, Hendrasto M, Hirabayashi J-I, 2008. Mechanism of explosive eruption revealed by geophysical observations at the Sakurajima, Suwanosejima and Semeru volcanoes. J. Volcanol. Geotherm. Res., 178, 1-9. https://doi.org/10.1016/j.jvolgeores.2007.10.010
There is no Emissions History data available for Suwanosejima.
A plume rises above Ontake, the summit crater of Suwanosejima. The 8-km-long island consists of a stratovolcano with two historically active summit craters. The dipping scarp at the top of the image opens towards the sea on the E flank and formed by edifice collapse. This is one of Japan's most frequently active volcanoes and has been in a state of intermittent Strombolian activity since 1949.
An ash plume erupts from the Suwanosejima summit crater, seen from a helicopter on 12 May 2001. Eruptions on the evening of 12 May and the morning of the 13th deposited up to 3 cm of ash in Toshima village, about 4 km NNW of the crater. After a quiet period of about 10 months eruptive activity had resumed on 19 December 2000 and continued intermittently until July 2004.
This photo of the NE slope of Suwanosejima was taken on 20 December 2000, the day after the onset of an explosive eruption. It shows the main active crater, Ontake (labeled 1), and two subsidiary craters (2 and 3). Explosive activity continued intermittently until July 2004.Maps are not currently available due to technical issues.
There are no samples for Suwanosejima in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.
| Copernicus Browser | The Copernicus Browser replaced the Sentinel Hub Playground browser in 2023, to provide access to Earth observation archives from the Copernicus Data Space Ecosystem, the main distribution platform for data from the EU Copernicus missions. |
| MIROVA | Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity. |
| MODVOLC Thermal Alerts | Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales. |
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WOVOdat
Single Volcano View Temporal Evolution of Unrest Side by Side Volcanoes |
WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
GVMID Data on Volcano Monitoring Infrastructure The Global Volcano Monitoring Infrastructure Database GVMID, is aimed at documenting and improving capabilities of volcano monitoring from the ground and space. GVMID should provide a snapshot and baseline view of the techniques and instrumentation that are in place at various volcanoes, which can be use by volcano observatories as reference to setup new monitoring system or improving networks at a specific volcano. These data will allow identification of what monitoring gaps exist, which can be then targeted by remote sensing infrastructure and future instrument deployments. |
| Volcanic Hazard Maps | The IAVCEI Commission on Volcanic Hazards and Risk has a Volcanic Hazard Maps database designed to serve as a resource for hazard mappers (or other interested parties) to explore how common issues in hazard map development have been addressed at different volcanoes, in different countries, for different hazards, and for different intended audiences. In addition to the comprehensive, searchable Volcanic Hazard Maps Database, this website contains information about diversity of volcanic hazard maps, illustrated using examples from the database. This site is for educational purposes related to volcanic hazard maps. Hazard maps found on this website should not be used for emergency purposes. For the most recent, official hazard map for a particular volcano, please seek out the proper institutional authorities on the matter. |
| IRIS seismic stations/networks | Incorporated Research Institutions for Seismology (IRIS) Data Services map showing the location of seismic stations from all available networks (permanent or temporary) within a radius of 0.18° (about 20 km at mid-latitudes) from the given location of Suwanosejima. Users can customize a variety of filters and options in the left panel. Note that if there are no stations are known the map will default to show the entire world with a "No data matched request" error notice. |
| UNAVCO GPS/GNSS stations | Geodetic Data Services map from UNAVCO showing the location of GPS/GNSS stations from all available networks (permanent or temporary) within a radius of 20 km from the given location of Suwanosejima. Users can customize the data search based on station or network names, location, and time window. Requires Adobe Flash Player. |
| DECADE Data | The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the Mapping Gas Emissions (MaGa) Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO2 to the atmosphere, but installing CO2 monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere. |
| Large Eruptions of Suwanosejima | Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA). |
| EarthChem | EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS). |
