All times are local unless otherwise stated.

Cleveland (United States) | 31 August-6 September 2011 | New Activity / Unrest Cite this Report
Cleveland Aleutian Ridge Volcanic Arc	On 30 August, AVO reported that satellite observations during the previous two weeks indicated that lava-dome growth at Cleveland had paused. AVO lowered the Volcano Alert Level to Advisory and the Aviation Color Code to Yellow. During 31 August-2 September cloud cover prevented views of the summit crater, but a thermal anomaly at the summit was observed during 3-5 September. Observations on 6 September indicated that the lava dome had resumed growth, reaching 120 m in diameter and filling the floor of the crater. AVO raised the Volcano Alert Level to Watch and the Aviation Color Code to 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)
Kilauea (United States) | 31 August-6 September 2011 | New Activity / Unrest Cite 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 but remained mostly stable below the inner ledge 75 m below the crater floor. Periodic 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 sources on the E portion of the crater floor fed a perched lava lake. Lava from a source at the W edge of the crater floor spread N and S along the base of the W crater wall and up to the base of the W, inactive wall of the perched pond. During 2-3 September a new perched pond fed from the W-edge source had formed. Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Kizimen (Russia) | 31 August-6 September 2011 | New Activity / Unrest Cite this Report
Kizimen Eastern Kamchatka Volcanic Arc	KVERT reported that during 26 August-1 September the number and magnitude of volcanic earthquakes at Kizimen continued to increase; about 1,000 earthquakes were detected daily. Satellite images showed a large bright thermal anomaly on the volcano all week and gas-and-steam plumes that drifted 60 km E on 26 and 29 August. Lava on the E flank continued to flow. In addition to strong fumarolic activity, video images from the previous week showed a new long fissure at the top of the volcano. The Aviation Color Code remained at Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Lewotobi (Indonesia) | 31 August-6 September 2011 | New Activity / Unrest Cite this Report
Lewotobi Sunda Volcanic Arc	CVGHM reported that during 26-31 August seismicity at Lewotobi increased. Plumes of "smoke" rose 15-50 m above the Lewotobi Perampuan crater rim; no other significant changes were visibly apparent. Based on the seismic data, the Alert Level was raised to 2 (on a scale of 1-4) on 31 August. Visitors and residents were advised not to approach the volcano within 1 km of the Lewotobi Perampuan crater. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Poas (Costa Rica) | 31 August-6 September 2011 | New Activity / Unrest Cite this Report
Poas Central America Volcanic Arc	On 31 August OVSICORI-UNA reported that since mid-July incandescence was visible during the day on the lava dome of Poás, which had not occurred since 1981, and was the result of changes in activity that had started several months before. OVSICORI-UNA speculated that the changes could be either from recent magma intrusion or a change in the hydrothermal plumbing system and noted the need to further analyze data from seismic, deformation, geochemical, and field measurements. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
Popocatepetl (Mexico) | 31 August-6 September 2011 | New Activity / Unrest Cite this Report
Popocatepetl Trans-Mexican Volcanic Belt	CENAPRED reported that on 29 August instances of emissions of gas, steam, and some ash from Popocatépetl increased. The next day an ash plume rose 1 km above the crater and drifted WNW, producing ashfall in San Pedro Nexapa (14 km NW) and Amecameca (19 km NW). CENAPRED noted that recent rain in the area may have contributed to the recent increase in activity. During 30-31 August there were 111 plumes of gas, steam, and some ash detected by the network, in addition to periods of harmonic tremor. Signals from detectors near drainages possibly indicated lahars. During 1-4 September the monitoring network registered 4-12 instances daily of emissions of gas, steam, and some ash. Periods of tremor continued to be detected. Source: Centro Nacional de Prevencion de Desastres (CENAPRED)

Aira (Japan) | 31 August-6 September 2011 | Continuing ActivityCite this Report
Aira Ryukyu Volcanic Arc	Based on information from JMA, the Tokyo VAAC reported that during 31 August-6 September explosions from Sakura-jima produced plumes that rose to altitudes of 1.2-3 km (4,000-10,000 ft) a.s.l. and drifted SW, S, and SE. According to a news article, the 660th explosive eruption in 2010 occurred on 3 September. The article also noted that as of 2 September, 607 grams of ash per square meter had fallen in Kagoshima (10 km W), compared to 753 grams for all of 2010, when the volcano had a record-high 896 explosive eruptions. Sources: Tokyo Volcanic Ash Advisory Center (VAAC), The Japan Times
Karymsky (Russia) | 31 August-6 September 2011 | Continuing ActivityCite this Report
Karymsky Eastern Kamchatka Volcanic Arc	KVERT reported that during 26 August-1 September moderate seismic activity continued at Karymsky, indicating that possible ash plumes rose to an altitude of 3 km (10,000 ft) a.s.l. Gas-and-steam plumes containing ash drifted 40 km E on 26 and 29 August. A thermal anomaly on the volcano was detected by satellite during 26 and 29-30 August. The Aviation Color Code remained at Orange. Based on information from Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 2 September an ash plume rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted NE. Ash plumes rose to an altitude of 2.1 km (7,000 ft) a.s.l. during 5-6 September and drifted SE and SW. Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Kamchatkan Volcanic Eruption Response Team (KVERT)
Kirishimayama (Japan) | 31 August-6 September 2011 | Continuing ActivityCite this Report
Kirishimayama Ryukyu Volcanic Arc	Based on notifications from JMA, the Tokyo VAAC reported that during 31 August-6 September ash plumes from Kirishima's Shinmoe-dake (Shinmoe peak) rose to altitudes of 1.5-2.1 km (5,000-7,000 ft) a.s.l. and drifted N, S, and SW. Source: Tokyo Volcanic Ash Advisory Center (VAAC)
Pagan (United States) | 31 August-6 September 2011 | Continuing ActivityCite this Report
Pagan Mariana Volcanic Arc	A Northern Mariana Islands status report noted that during 26 August-2 September low-level vapor plumes from Pagan, possibly containing minor amounts of ash, were visible in satellite imagery. Reports from people on Pagan Island also indicated intermittent low-level but diffuse ash emissions and trace amounts of ashfall on parts of the island. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory. Source: Emergency Management Office of the Commonwealth of the Mariana Islands and United States Geological Survey Volcano Hazards Program
Puyehue-Cordon Caulle (Chile) | 31 August-6 September 2011 | Continuing ActivityCite this Report
Puyehue-Cordon Caulle Andean Southern Volcanic Arc	Based on seismicity during 31 August-5 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 satellite and camera observations of the vent, plumes detected in satellite imagery during 31 August-1 September drifted SE and SW. A plume observed by an area camera on 1 September rose 1 km above the crater. On 3 and 5 September plumes observed in satellite imagery drifted 30-80 km SE and E. The Alert Level remained at Red. Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
Sheveluch (Russia) | 31 August-6 September 2011 | Continuing ActivityCite this Report
Sheveluch Eastern Kamchatka Volcanic Arc	KVERT reported that seismic activity at Shiveluch was moderate during 26 August-1 September, and indicated that possible ash plumes rose to an altitude of 8.6 km (28,200 ft) a.s.l. on 28 August. Ground-based observers noted fumarolic activity during 26, 28, and 30-31 August, and an ash plume that rose to an altitude of 6 km (19,700 ft) a.s.l. on 28 August. A thermal anomaly on the volcano was observed in satellite imagery on 29 and 31 August. The Aviation Color Code remained at Orange. Based on information from Yelizovo Airport (UHPP) and KVERT, the Tokyo VAAC reported that on 3 September an ash plume rose to an altitude of 5.8 km (19,000 ft) a.s.l. and drifted NE. Subsequent images that day showed that the ash had dissipated. Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Kamchatkan Volcanic Eruption Response Team (KVERT)

Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 20,322 individual reports over 1,229 weeks (average of 17 per week) on 336 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)