Aira (Japan) | 15 August-21 August 2012 | Continuing ActivityCite this Report

JMA reported that during 17-20 August explosions from Sakura-jima's Showa Crater ejected tephra as far as 1,300 m from the crater. Based on information from JMA, the Tokyo VAAC reported that explosions during 17-21 August produced plumes that rose to altitudes of 2.4-3.4 km (8,000-11,000 ft) a.s.l. and drifted N and NW. Pilots observed ash plumes during 18-20 August that rose to altitudes of 2.1-4.3 km (7,000-14,000 ft) a.s.l. and drifted S, SW, and W.

According to a news report, the total amount of ash emitted from Sakura-jima from January to July was more than two times larger than all of 2011, when a record number of eruptions had occurred.

Sources: Japan Meteorological Agency (JMA), Tokyo Volcanic Ash Advisory Center (VAAC)

Batu Tara (Indonesia) | 15 August-21 August 2012 | Continuing ActivityCite this Report

Based on analyses of satellite imagery, the Darwin Volcanic Ash Advisory Centre (VAAC) reported that during 15-21 August ash plumes from Batu Tara rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 35-95 km W, NW, and NNW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Cleveland (United States) | 15 August-21 August 2012 | Continuing ActivityCite this Report

AVO reported that nothing unusual was observed at Cleveland in cloudy to partly cloudy satellite images during 15-16, 18, and 20-21 August. A small explosion was detected on 17 August by seismic and infrasound instruments on neighboring volcanoes. No evidence of an ash cloud was visible in satellite images following the event. Another small explosion on 19 August produced a low-level ash cloud, observed in satellite imagery, that drifted SE. Retrospective analysis of ground-coupled airwaves in seismic data further confirmed the explosion. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Etna (Italy) | 15 August-21 August 2012 | Continuing ActivityCite this Report

Sezione di Catania - Osservatorio Etneo reported that a new phase of activity at Etna's Bocca Nuova summit crater started on 2 July, was virtually continuous for three weeks until 24 July, then rapidly decreased. During the first 10 days explosions were separated by quiet intervals lasting several minutes, then later became more continuous. During periods of the strongest activity, some lava bombs were ejected beyond the crater rim, landing on a gently sloping area E of the crater. Lava was emitted during 4-24 July from vents on the flanks of the pyroclastic cone that had begun to grow around the explosive vent. Rarely, lava was emitted from the main explosive vent. The lava progressively covered the crater floor next to the pyroclastic cone, which had grown 30-40 m, before the activity ceased on 24 July. Frequent ash emissions observed the next day were mostly due to explosions, and possibly from minor collapses of the summit area of the new cone. Concurrent with the decrease in eruptive activity, volcanic tremor amplitude dropped to background levels.

Episodic activity occurred during 26 July-11 August. At daybreak on 26 July, strong incandescence marked the onset of the first episode of activity within Bocca Nuova, which had the same characteristics as the previous activity; frequent Strombolian explosions were accompanied by lava flow emissions from a vent located on the W flank of the cone. The next day, the lava had almost completely filled the central subsidence pit on the floor of Bocca Nuova, and the cone had grown in height. The activity then decreased, and essentially ceased by the evening. There were intermittent ash emissions on 28 July, and volcanic tremor amplitude decreased to background levels.

The second episode, during 29 July-1 August, was characterized by small Strombolian explosions and lava emission from a vent located on the S flank of the pyroclastic cone. Volcanic tremor amplitude showed strong oscillations, but never reached the same peak levels associated with the 26-27 July episode. Volcanic tremor amplitude dropped sharply on 1 August, marking the cessation of the activity; a few ash emissions were observed the next day.

The third episode began on 3 August with a rapid increase in the volcanic tremor amplitude and strong incandescence from Bocca Nuova, signaling the beginning of Strombolian activity and lava emissions onto the crater floor. Activity ceased the next day, and was followed by weak residual activity within Bocca Nuova, which generated small ash clouds. The fourth episode began on 6 August and ended the next day, and showed essentially the same characteristics as the previous episode.

The fifth episode began on 10 August and was again marked by a rapid increase in volcanic tremor amplitude; at nighl, bright glow illuminated the gas plume rising from the crater, which was visible up to tens of kilometers away. Some of the explosions ejected incandescent pyroclastic material well above the crater rim. The activity started to decrease just after midnight and then ended on 11 August. Subsequently, ash emissions resumed, which were particularly frequent on 13 August, and which produced small, brownish-gray clouds of fine-grained tephra. Some of the ash emissions later that evening were accompanied by ejected incandescent material; volcanic tremor amplitude, however, remained at background levels.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

Fuego (Guatemala) | 15 August-21 August 2012 | Continuing ActivityCite this Report

INSIVUMEH reported that during 15-16 and 18-21 August lava flows from Fuego traveled 250-500 m down the Taniluyá drainage (SW), generating block avalanches that reached vegetated areas. On 17 August 20-m-wide lahars traveled SE down the Las Lajas and El Júte drainages, carrying blocks 1.5 m in diameter. Steam rose from the deposits in Las Lajas. Explosions were heard during 18-29 August but weather conditions prevented observations. Explosions during 19-21 August produced ash plumes that rose 100-300 m above the crater and drifted N, NW, W, and SW. Incandescent material was ejected 40-100 m above the crater at night. In a special report issued on 21 August, INSIVUMEH stated that seismicity had increased, along with degassing and rumbling sounds. Incandescent material was ejected 150 m above the crater, and lava flows traveled 500 m down the El Júte and Taniluyá drainages, generating block avalanches that reached vegetated areas.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Galeras (Colombia) | 15 August-21 August 2012 | Continuing ActivityCite this Report

INGEOMINAS reported that both earthquake occurrence and magnitude were low at Galeras during 14-21 August. Sulfur dioxide emissions fluctuated, but remained at moderate levels. An ash plume rose from the crater on 16 August. White plumes were observed during 16 and 18-21 August. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

Source: Servicio Geológico Colombiano (SGC)

Karymsky (Russia) | 15 August-21 August 2012 | Continuing ActivityCite this Report

KVERT reported moderate seismic activity from Karymsky during 10-20 August. Satellite imagery showed a weak thermal anomaly on the volcano during 10-13, 15, and 18-20 August. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Kilauea (United States) | 15 August-21 August 2012 | Continuing ActivityCite this Report

During 15-21 August HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Occasional measurements indicated that the gas plume from the vent continued to deposit variable amounts of spatter and Pele's hair onto nearby areas. There were no significant geologic changes in Pu'u 'O'o Crater; the glowing vent at the base of the SE flank continued to glow brightly, and incandescence emanated from a lava lake in a pit on the NE part of the crater floor. A small, new pit crater opened on the S crater floor on 17 August. Lava flows were active on the pali and the coastal plain. The active lava-flow front was about 2 km from the ocean on 18 August.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Nevado del Ruiz (Colombia) | 15 August-21 August 2012 | Continuing ActivityCite this Report

According to INGEOMINAS, the Observatorio Vulcanológico and Sismológico de Manizales reported that during 15-16 and 18-21 August variations in volcanic tremor amplitude were detected at Nevado del Ruiz, possibly associated with continuing gas and ash emissions. Earthquakes indicative of fracturing rock were located SE at depths of 1.5-4 km, with magnitudes less than 1. One event on 18 August was a M 2, located 1.17 km SW of Arenas Crater at a depth of 3.6 km. Web cameras showed gas-and-ash plumes rising 400 m and drifting W and NW during 15-16 August. A gas plume rose 400 m and drifted NW on 19 August. During 20-21 August field measurements and analysis of satellite imagery showed a significant amount of sulfur dioxide in the atmosphere. The Alert Level remained at II (Orange; "eruption likely within days or weeks").

Source: Servicio Geológico Colombiano (SGC)

Popocatepetl (Mexico) | 15 August-21 August 2012 | Continuing ActivityCite this Report

CENAPRED reported that during 15-21 August seismicity at Popocatépetl indicated continuing gas-and-steam emissions that may have contained ash; cloud cover often prevented visual observations of the volcano. Incandescence from the crater was observed at night. A gas-and-ash plume rose from the crater on 15 August, and steam-and-gas plumes rose as high as 1 km and drifted NW the next day. On 17 August seismicity significantly increased. Incandescent tephra ejected from the crater fell onto the flanks and rolled 800 m. On 18 August an ash plume rose 2 km above the crater and drifted E. Ejected incandescent tephra fell onto the SE flank. A small ash emission and ejected incandescent tephra were observed on 19 August. The next day a steam-and-gas plume rose 900 m and drifted NNW. The Alert Level remained at Yellow, Phase Three.

Source: Centro Nacional de Prevencion de Desastres (CENAPRED)

Santa Maria (Guatemala) | 15 August-21 August 2012 | Continuing ActivityCite this Report

INSIVUMEH reported that during 15-16 and 18-20 August explosions from Santa María's Santiaguito lava-dome complex produced ash plumes that rose 400-900 m above Caliente dome and drifted 10 km W and NW. Block avalanches originated from the fronts of multiple active flows. White gas plumes rose 200 m and drifted WNW and SW. During 18-20 August ashfall was reported in Monte Claro (S), El Rosario (45 km SW), Palajunoj (S), and surrounding areas. Sounds resembling avalanches were reported on 21 August, however weather conditions prevented visual observations.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Sheveluch (Russia) | 15 August-21 August 2012 | Continuing ActivityCite this Report

KVERT reported that during 10-18 August weak seismic activity was detected at Shiveluch. Observers noted gas-and-steam activity during 15-17 August; weather conditions prevented observations of the volcano on the other days. Satellite imagery showed a thermal anomaly on the lava dome during 10, 12-13, and 18-19 August. Seismic activity increased to moderate levels and hot avalanches were observed during 19-20 August. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)