All times are local unless otherwise stated.

Cleveland (United States) | 7 September-13 September 2011 | New Activity / Unrest Cite this Report
Cleveland Aleutian Ridge Volcanic Arc	AVO reported that although cloud cover often prevented observations of Cleveland during 7-12 September, a thermal anomaly on the lava dome was visible during 8-9 and 12 September. A possible anomaly was visible on 10 September. The anomalies suggested that lava-dome growth was continuing, although no activity was observed in partly cloudy satellite images during 12-13 September. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network. Source: US Geological Survey Alaska Volcano Observatory (AVO)
Etna (Italy) | 7 September-13 September 2011 | New Activity / Unrest Cite this Report
Etna Sicily Volcanic Province	Sezione di Catania - Osservatorio Etneo reported that the thirteenth paroxysmal eruptive episode of 2011 took place at the New SE Crater of Etna on the morning of 8 September. Prior to the episode, a few emissions of ash from the New SE Crater occurred on 6 September. Sporadic, very weak Strombolian explosions from the crater started during the late evening on 7 September, and then continued in a subdued manner through the night. On 8 September a series of ash emissions were followed by a rapid increase both in the intensity and frequency of Strombolian explosions. Loud detonations were audible across a vast sector of Etna's densely populated SE to E flanks. Simultaneously the volcanic tremor amplitude sharply increased and shifted from below the NE Crater toward the SE Crater. The Strombolian activity turned into a pulsating lava fountain, accompanied by increasing amounts of volcanic ash. Lava fountaining and ash emissions became more vigorous. Lava flowed through a deep breach in the E crater rim and along the fracture that had opened on the SE side of the cone during 29 August. The lava overflow was accompanied by repeated collapse and rockfalls from unstable portions of the cone in that area. Later brief periods of repeated emissions of brown ash mixed with white water vapor occurred from two or three vents on the N flank of the New SE Crater cone, in an area of the lava overflows from the N rim of the crater that had started shortly after the onset of the activity. The paroxysmal activity ceased in the evening and was followed by a series of progressively more passive ash emissions. Lava flows descended on the W slope of the Valle del Bove; expansion of the most advanced lava fronts continued for some time after feeding of the lava had ceased, mostly due to gravitational flow. Small active lava flows were observed for many hours after the cessation of the paroxysmal activity, remaining confined to the immediate vicinity of the crater. The pyroclastic cone that grew around the New SE Crater during the recent series of eruptive episodes had undergone significant morphological changes. The S and N crater rims had further increased in height, whereas degradation and mass wasting on the SE flank had become more conspicuous. A large chunk of rock on the lower SE flank was rotated and uplifted, forming a steep-sided "spine" about 20-30 m tall, with locally vertical and sub-vertical flanks. Source: Sezione di Catania - Osservatorio Etneo (INGV)
Hierro (Spain) | 7 September-13 September 2011 | New Activity / Unrest Cite this Report
Hierro Canary Volcanic Province	Instituto Geográfico Nacional (IGN) reported that since 16 July, seismicity at Hierro was high above the background levels. Until 7 September more than 6,200 events had been located, most of them in the El Golfo area with hypocenters that were 10 km deep, all magnitudes were below 3. The seismic activity alternated between relatively calm periods and high-energy periods. GPS local network stations showed deformations of about 2 cm. High rates of carbon dioxide flux were measured in the anomalous area. Source: Instituto Geográfico Nacional (IGN)
Ibu (Indonesia) | 7 September-13 September 2011 | New Activity / Unrest Cite this Report
Ibu Halmahera Volcanic Arc	CVGHM reported mostly clear conditions at Ibu during January-8 September and that white-to-gray plumes were observed rising 200-400 m above the craters. On 20 August observers from the nearby villages of Goin and Duono noted multiple eruptions from the S, E, and N craters. Eruption "smoke" rose 50-250 m above the craters and an avalanche traveled 300 m. Seismicity indicating avalanches occurred on average 45 times per day during January-8 September. Other types of seismic signals fluctuated during the time period but stabilized or decreased towards September. Based on visual observations and seismicity, CVGHM lowered the Alert Level to 2 (on a scale of 1-4) on 8 September. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Merapi (Indonesia) | 7 September-13 September 2011 | New Activity / Unrest Cite this Report
Merapi Sunda Volcanic Arc	CVGHM reported that during 29 August-4 September white solfatara plumes rose at most 350 m above Merapi and drifted W. On 4 September small avalanches traveled 700 m SW. The Alert Level remained at 2 (on a scale of 1-4). Based on a pilot observation, the Darwin VAAC reported that on 8 September an ash plume rose to an altitude of 3.7 km (12,000 ft) a.s.l. and drifted almost 30 km N. Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)
Ranakah (Indonesia) | 7 September-13 September 2011 | New Activity / Unrest Cite this Report
Ranakah Sunda Volcanic Arc	Based on visual observations and seismic data analyses of the Anak Ranakah lava dome since December 2010, CVGHM raised the Alert Level on 26 August to 2 (on a scale of 1-4). During 26 August-7 September white plumes rose 5-10 m above the lava dome. Seismic activity continued to increase, prompting CVGHM to again raised the Alert Level, to 3, on 8 September. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Soputan (Indonesia) | 7 September-13 September 2011 | New Activity / Unrest Cite this Report
Soputan Sangihe Volcanic Arc	CVGHM reported that seismicity at Soputan significantly decreased after the eruption on 14 August until 7 September. White plumes rose at most 200 m above the crater during 14-18 August, up to 150 m above the crater during 19-28 August, and as high as 100 m above the crater during 29 August-7 September. The Alert Level was lowered to 2 (on a scale of 1-4) on 8 September. Visitors and residents were prohibited from going within a 4-km radius of the crater, a change from the 6-km restricted zone in place when the Alert level was at 3. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Tambora (Indonesia) | 7 September-13 September 2011 | New Activity / Unrest Cite this Report
Tambora Sunda Volcanic Arc	Based on visual observation and seismic data, CVGHM reported an increase in activity at Tambora that started in April. Therefore, on 30 August, the Alert Level was raised to 2 (on a scale of 1-4). During 30 August-8 September seismicity continued to increase. Diffuse white plumes were observed on 5 September and rose 10 m above the crater rim. On 8 September the Alert Level was raised to 3 (on a scale of 1-4). Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Aira (Japan) | 7 September-13 September 2011 | Continuing ActivityCite this Report
Aira Ryukyu Volcanic Arc	Based on information from JMA, the Tokyo VAAC reported that during 9-13 September explosions from Sakura-jima produced plumes that rose to altitudes of 1.8-2.7 km (6,000-9,000 ft) a.s.l. and drifted NW and N. On 9 September a pilot observed an ash plume that rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted NW. Source: Tokyo Volcanic Ash Advisory Center (VAAC)
Batu Tara (Indonesia) | 7 September-13 September 2011 | Continuing ActivityCite this Report
Batu Tara Sunda Volcanic Arc	Based on analyses of satellite imagery, the Darwin VAAC reported that during 8-13 September ash plumes from Batu Tara rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 37-65 km NW and W. Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Dukono (Indonesia) | 7 September-13 September 2011 | Continuing ActivityCite this Report
Dukono Halmahera Volcanic Arc	Based on analyses of satellite imagery, the Darwin VAAC reported that on 13 September an ash plume from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 75 km NW. Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Karymsky (Russia) | 7 September-13 September 2011 | Continuing ActivityCite this Report
Karymsky Eastern Kamchatka Volcanic Arc	KVERT reported that during 2-9 September moderate seismic activity continued at Karymsky, indicating that possible ash plumes rose to an altitude of 3.5 km (11,500 ft) a.s.l. A thermal anomaly on the volcano was detected daily in satellite imagery. The Aviation Color Code remained at Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Kilauea (United States) | 7 September-13 September 2011 | Continuing ActivityCite this Report
Kilauea Hawaiian-Emperor Hotspot Volcano Group	During 31 August-6 September, HVO reported that the level of the lava-lake surface in the deep pit within Kilauea's Halema'uma'u crater periodically fluctuated and circulated. Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and occasionally fresh spatter nearby. At Pu'u 'O'o' crater, lava from E, W, and S-central sources on the crater floor fed an eastern and a western perched lava lake during 7-8 September. Lava also covered much of the crater floor, rising to within 5 m of a low point on the E crater rim. During 9-10 September a large amount of lava from a new source of effusion at the NE edge of the crater covered most of the crater floor. On 10 September a pilot confirmed that lava overtopped the E rim and fed a short lava flow. Not long after that the effusion rate decreased and lava fed only the two perched lava lakes. During 11-13 September the lava lakes mostly circulated and, by 12 September, had overflowed onto the crater floor. Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Kizimen (Russia) | 7 September-13 September 2011 | Continuing ActivityCite this Report
Kizimen Eastern Kamchatka Volcanic Arc	KVERT reported that during 2-9 September the magnitude of volcanic earthquakes at Kizimen remained high; about 1,000 earthquakes were detected daily. Satellite images showed a large thermal anomaly on the volcano. Lava on the E flank continued to flow and video images showed strong fumarolic activity. The Aviation Color Code remained at Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Puyehue-Cordon Caulle (Chile) | 7 September-13 September 2011 | Continuing ActivityCite this Report
Puyehue-Cordon Caulle Southern Andean Volcanic Arc	Based on seismicity during 7-13 September, OVDAS-SERNAGEOMIN reported that the eruption from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, continued at a low level. Although cloudy weather mostly prevented observations of the vent, plumes detected in satellite imagery during 7-8, 10, and 12 September drifted 10-60 km NE, E, and SE. A plume observed by an area camera on 12 September rose less than 1 km above the crater. The next day a plume rose less than 4 km above the crater and was observed in satellite imagery drifting 35 km NE. The Alert Level remained at Red. Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
Sheveluch (Russia) | 7 September-13 September 2011 | Continuing ActivityCite this Report
Sheveluch Eastern Kamchatka Volcanic Arc	KVERT reported that seismic activity at Shiveluch was moderate during 2-9 September, and indicated that possible ash plumes rose to an altitude of 4.3 km (14,100 ft) a.s.l. during 2-3 September. Ground-based observers noted fumarolic activity during the week, and an ash plume that rose to an altitude of 4 km (19,700 ft) a.s.l. on 3 September. Also on 3 September an ash cloud 19 by 11 km was observed in satellite imagery drifting 20 km E. A thermal anomaly on the volcano was also observed in satellite imagery on 5 and 7 September. The Aviation Color Code remained at Orange. Based on information from KEMSD, the Tokyo VAAC reported that on 10 September an eruption produced a plume that rose to an altitude of 6.7 km (22,000 ft) a.s.l. Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Kamchatkan Volcanic Eruption Response Team (KVERT)
Suwanosejima (Japan) | 7 September-13 September 2011 | Continuing ActivityCite this Report
Suwanosejima Ryukyu Volcanic Arc	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)

Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 20,627 individual reports over 1,243 weeks (average of 17 per week) on 338 different volcanoes.

Use the dropdowns to choose the year and week for archived Weekly Reports.

 News Feeds and Google Placemarks

 Criteria & Disclaimers

The Weekly Volcanic Activity Report does not necessarily include all volcanic activity that occurred on Earth during the week. More than a dozen volcanoes globally have displayed more-or-less continuous eruptive activity for decades or longer, and such routine activity is typically not reported here. Moreover, Earth's sea-floor volcanism is seldom reported even though in theory it represents the single most prolific source of erupted material. The Weekly Volcanic Activity Report summarizes volcanic activity that meets one or more of the following criteria:

- A volcano observatory raises or lowers the alert level at the volcano.
- A volcanic ash advisory has been released by a volcanic ash advisory center (VAAC) stating that an ash cloud has been produced from the volcano.
- A verifiable news report of new activity or a change in activity at the volcano has been issued.
- Observers have reported a significant change in volcanic activity. Such activity can include, but is not restricted to, pyroclastic flows, lahars, lava flows, dome collapse, or increased unrest.

Volcanoes are included in the "New Activity/Unrest" section of the Weekly Volcanic Activity Report if the activity occurs after at least 3 months of quiescence. Once a volcano is included in the "New Activity/Unrest" section, updates will remain in that section unless the activity continues for more than 1 month without escalating, after which time updates will be listed in the "Continuing Activity" section. Volcanoes are also included in the "New Activity/Unrest" section if the volcano is undergoing a period of relatively high unrest, or increasing unrest. This is commonly equal to Alert Level Orange on a scale of Green, Yellow, Orange, Red, where Red is the highest alert. Or alert level 3 on a scale of 1-4 or 1-5.

It is important to note that volcanic activity meeting one or more of these criteria may occur during the week, but may not be included in the Weekly Volcanic Activity Report because we did not receive a report.

1. The Weekly Volcanic Activity Report is intended to provide timely information about global volcanism on a weekly basis. Consequently, the report is generated rapidly by summarizing volcanic reports from various sources, with little time for fact checking. The accuracy of the Weekly Volcanic Activity Report is dependent upon the quality of the volcanic activity reports we receive. Reports published in the Bulletin of the Global Volcanism Network are cover longer time periods and are more carefully reviewed, although all of the volcanoes discussed in the Weekly Volcanic Activity Report are not necessarily reported in the Bulletin. Because of our emphasis on rapid reporting on the web we have avoided diacritical marks. Reports are updated on the Weekly Volcanic Activity Report web page as they are received, therefore information may be included regarding events that occurred before the current report period.

2. Rapidly developing events lead to coverage that is often fragmentary. Volcanoes, their eruptions, and their plumes and associated atmospheric effects are complex phenomena that may require months to years of data analysis in order to create a comprehensive summary and interpretation of events.

3. Preliminary accounts sometimes contain exaggerations and "false alarms," and accordingly, this report may include some events ultimately found to be erroneous or misleading.

4. Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.

5. USGS Disclaimer Statement for this Website:

Information presented on this website is considered public information and may be distributed or copied. Use of appropriate byline/photo/image credit is requested. We strongly recommend that USGS data be acquired directly from a USGS server and not through other sources that may change the data in some way. While USGS makes every effort to provide accurate and complete information, various data such as names, telephone numbers, etc. may change prior to updating. USGS welcomes suggestions on how to improve our home page and correct errors. USGS provides no warranty, expressed or implied, as to the accuracy, reliability or completeness of furnished data.

Some of the documents on this server may contain live references (or pointers) to information created and maintained by other organizations. Please note that USGS does not control and cannot guarantee the relevance, timeliness, or accuracy of these outside materials.

For site security purposes and to ensure that this service remains available to all users, this government computer system employs software programs to monitor network traffic to identify unauthorized attempts to upload or change information, or otherwise cause damage. Unauthorized attempts to upload information or change information on this website are strictly prohibited and may be punishable under the Computer Fraud and Abuse Act of 1986 and the National Information Infrastructure Protection Act. Information may also be used for authorized law enforcement investigations. (Last modified September 21, 1999.)

U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA
URL: https://volcano.si.edu/reports_weekly.cfm

 Acronyms and Abbreviations

a.s.l. - above sea level

AVO - Alaska Volcano Observatory

AVHRR - Advanced Very High Resolution Radiometer

CENAPRED - Centro Nacionale de Prevencion de Desastres (México)

CONRED - Coordinadora Nacional para la Reducción de Desastres

COSPEC - Correlation Spectrometer

CVGHM (formerly VSI) - Center of Volcanology and Geological Hazard Mitigation

CVO - Cascades Volcano Observatory (USGS)

GMS - Geostationary Meteorological Satellite

GOES - Geostationary Operational Environmental Satellite

GVO - Goma Volcano Observatory

GVP - Global Volcanism Program (Smithsonian Institution)

HVO - Hawaiian Volcano Observatory (USGS)

ICE - Instituto Costarricense de Electricidad (Costa Rica)

IG - Instituto Geofísico (Ecuador)

IGNS - Institute of Geological and Nuclear Sciences (New Zealand) - now GNS Science

INETER - Instituto Nicaragüense de Estudios Territoriales (Nicaragua)

INGEMMET - Instituto Geológical Minero y Metalúrgico (Peru)

INGEOMINAS - Instituto Colombiano de Geología y Minería (Colombia)

INGV-CT - Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Catania (Italy)

INSIVUMEH - Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hidrologia (Guatemala)

IRD - Institut de Recherche pour le Développement (France)

JMA - Japanese Meteorological Agency

KEMSD - Kamchatkan Experimental and Methodical Seismilogical Department

KVERT - Kamchatkan Volcanic Eruption Response Team

M - magnitude

METEOSAT - Meteorological Satellite

MEVO - Mount Erebus Volcano Observatory

MODIS - Moderate Resolution Imaging Spectroradiometer

MVO - Montserrat Volcano Observatory

MWO - Meteorological Watch Office

NEIC - National Earthquake Information Center

NIED - National Research Institute for Earth Science and Disaster Prevention (Japan)

NOAA - National Oceanic and Atmospheric Administration

NOTAM - Notice to Airmen

OVDAS - Observatorio Volcanologico de los Andes del Sur (Chile)

OFDA - Office of US Foreign Disaster Assistance

ONEMI - Oficina Nacional de Emergencia - Ministerio del Interior (Chile)

OVPDLF - Observatoire Volcanologique du Piton de la Fournaise (France)

OVSICORI-UNA - Observatorio Vulcanologico y Sismologico de Costa Rica, Universidad Nacional (Costa Rica)

PHIVOLCS - Philippine Institute of Volcanology and Seismology (Philippines)

RSAM - Real-time Seismic Amplitude Measurement

RVO - Rabaul Volcano Observatory

SERNAGEOMIN - Servicio Nacional de Geologia y Mineria (Chile)

SIGMET - Significant Meteorological Information

SNET - Servicio Nacional de Estudios Territoriales (El Salvador)

SVERT - Sakhalin Volcanic Eruption Response Team (Russia)

USAID - US Agency for International Development

USGS - United States Geological Survey

UTC - Coordinated Universal Time

VAAC - Volcanic Ash Advisory Center

VAFTAD - Volcanic Ash Forecast Transport And Dispersion

VDAP - Volcano Disaster Assistance Program (USGS)

VHP - Volcano Hazards Program (USGS)

VRC - Volcano Research Center (Japan)