All times are local unless otherwise stated.

Cerro Hudson (Chile) | 26 October-1 November 2011 | New Activity / Unrest Cite this Report
Cerro Hudson Andean Southern Volcanic Arc	OVDAS-SERNAGEOMIN reported three new craters at Cerro Hudson following increased seismicity that was detected during 25-26 October. At 1908 on 25 October an M 4.6 volcano-tectonic earthquake occurred at a depth of 19 km, followed by a seismic swarm starting at 2149. More than 100 events, with depths ranging from 15 to 25 km, were recorded through the next day; 12 of the events were M 3, and three events were M 4. Scientists aboard an overflight on 26 October observed a white plume with some ash content that rose 1.5 km and lahars in Rio Huemul, to the W. The Alert Level was raised to Level 5 - Red. A very low-frequency M 4.3 earthquake occurred that same day at a depth of 15 km. Five earthquakes per hour were recorded between 1600 on 26 October and 1600 on 27 October. Most of the earthquakes were volcano-tectonic events with magnitudes lower that 3.6 and located W of the caldera at depths between 3 and 25 km. The earthquake hypocenters became shallower with time. The most significant event, a M 3.6, occurred at 0227 on 27 October and was located in the SW edge of the crater. Very low-frequency earthquakes possibly indicated magma movement. SERNAGEOMIN staff aboard an overflight on 27 October observed three craters along the S, SE edge of the caldera, with diameters of 200, 300, and 500 m. Mostly white plumes rose above the two smaller craters. The larger, southern-most crater emitted a plume with a greater ash content that rose 5 km above the crater. Satellite imagery showed a plume drifting 12 km SE. In response to the raised Alert Level, ONEMI reported that 128 people were evacuated from areas within a 45-km radius of the volcano, defined as high-risk zone. One earthquake per hour was recorded between 1600 on 27 October and 1600 on 28 October. The majority of the earthquakes were characterized as long-period with magnitudes less than 2.2. During an overflight on 28 October, scientists observed a gas plume with a very low ash content rise 3-4 km above the craters. Seismicity continued to decrease during 28-29 October. Scientists conducting an overflight noted that a gas plume with some ash rose 1 km above the craters and drifted 5-8 km NE. They also confirmed that a large lahar had traveled down the Rio Huemul and another branch of the river during the initial phase of the eruption. During another observation flight on 30 October, scientists saw plumes with minor ash rising 0.8 km from two of the three craters. ONEMI noted that the total number of evacuees had reached 140. On 31 October scientists observed gas plumes rising 0.5 km above the craters and drifting SE. On 1 November scientists observed an explosion and an accompanying ash plume that rose 1.5 km above the active craters. They also noted subsequent minor explosions and ash emissions. Sources: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI), Servicio Nacional de Geología y Minería (SERNAGEOMIN)
Gaua (Vanuatu) | 26 October-1 November 2011 | New Activity / Unrest Cite this Report
Gaua Vanuatu Volcanic Arc	Based on a hazards assessment during 17-18 October, the Vanuatu Geohazards Observatory reported that Gaua had been emitting ash since September. Ash fell on western parts of the island. The Alert Level remained at 1 (on a scale of 0-4). Source: Vanuatu Meteorology and Geohazards Department (VMGD)
Hierro (Spain) | 26 October-1 November 2011 | New Activity / Unrest Cite this Report
Hierro Canary Volcanic Province	Instituto Geográfico Nacional (IGN) reported that during 26 October-1 November tremor continued to be registered by every seismic station on El Hierro Island; 540 seismic events were registered and located, and the mean amplitude increased slightly during the last two days. Most of the events were located offshore to the N of the island, at depths of 16-23 km. The maximum magnitude was 3.9, and 36 of the total events were felt by residents at a maximum intensity value of IV using EMS-98 (European Macroseismic Scale). The total number of located events since 17 July was 10,930. Preliminary analysis of GPS deformation data showed an inflation-deflation sequence at one station on the N side of the island, with the main deformation trending N-S and in vertical components. GPS stations located in the W and S showed different behavior, with mean deformations to the SW and NE, respectively. Source: Instituto Geográfico Nacional (IGN)

Aira (Japan) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Aira Ryukyu Volcanic Arc	Based on information from JMA, the Tokyo VAAC reported that during 26 October-1 November explosions from Sakura-jima produced plumes that rose to altitudes of 1.8-3.4 km (6,000-11,000 ft) a.s.l. and drifted NW, W, SW, S, and SE. Satellite imagery on 26 October detected ash plumes that later dissipated. A pilot observed an ash plume on 31 October that rose to an altitude of 2.7 km (9,000 ft) a.s.l. Source: Tokyo Volcanic Ash Advisory Center (VAAC)
Batu Tara (Indonesia) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Batu Tara Sunda Volcanic Arc	Based on analyses of satellite imagery, the Darwin VAAC reported that on 27 October an ash plume from Batu Tara rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted about 45 km W. Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Bezymianny (Russia) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Bezymianny Eastern Kamchatka Volcanic Arc	KVERT reported that during 21-28 October seismic activity at Bezymianny was low. A thermal anomaly was observed in satellite imagery during 23-25 October, and fumarolic activity was observed during 23 and 25-26 October. The Aviation Color Code remained at Yellow. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Cleveland (United States) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Cleveland Aleutian Ridge Volcanic Arc	AVO reported that a radar image from 23 October indicated a lowering of the lava dome surface in Cleveland's summit crater. During 26 October-1 November cloud cover prevented views of the lava dome. 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)
Dukono (Indonesia) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Dukono Halmahera Volcanic Arc	Based on analyses of satellite imagery, the Darwin VAAC reported that during 27 October-1 November ash plumes from Dukono rose to altitudes of 2.1-2.7 km (7,000-9,000 ft) a.s.l. and drifted 35-110 km W, NW, and NE. Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Gorely (Russia) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Gorely Kuril Volcanic Arc	KVERT reported that during 21-28 November seismic activity from Gorely was at moderate levels and volcanic tremor was detected. Satellite imagery showed a weak thermal anomaly over the volcano during 21-25 November. The Aviation Color Code level remained at Yellow. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Karymsky (Russia) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Karymsky Eastern Kamchatka Volcanic Arc	KVERT reported that seismic activity continued at a moderate level at Karymsky during 21-28 October, and indicated that possible ash plumes rose to an altitude of 3.7 km (12,100 ft) a.s.l. during 20 and 23-24 October. Satellite imagery showed a daily thermal anomaly on the volcano and an ash plume that rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted 15 km NE on 26 October. The Aviation Color Code remained at Orange. Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Kamchatkan Volcanic Eruption Response Team (KVERT)
Kilauea (United States) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Kilauea Hawaiian-Emperor Hotspot Volcano Group	During 26 October-1 November, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater, remaining below the inner ledge (75 m below the crater floor). Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and fresh spatter nearby. Incandescence emanated from the E and W edges of the Pu'u 'O'o crater floor and from the 21 September fissure on the upper E flank of the Pu'u 'O'o cone. On 30 October incandescence was seen from a new area high on the W edge of a depression in the crater floor. Lava flows remained active to the SE of Pu'u 'O'o during 26-30 October, but were more sluggish during 31 October-1 November. Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Kizimen (Russia) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Kizimen Eastern Kamchatka Volcanic Arc	KVERT reported that during 21-28 October there was moderate seismic activity at Kizimen; the number of volcanic earthquakes decreased from 105 to 30 during 21-24 October. A thermal anomaly on the volcano was detected daily in satellite images. Video observations on 20 October showed a small pyroclastic flow on the NE flank and later ashfall on the flanks. Gas-and-steam activity was observed during 20-21 and 23-26 October. A large lava flow on the NE flank continued to effuse, and incandescence from both the lava flows and the crater was noted at night. The Aviation Color Code remained at Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Lokon-Empung (Indonesia) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Lokon-Empung Sangihe Volcanic Arc	According to a news article, a gray plume rose 1.2 km above Tompaluan crater, in the saddle between the Lokon-Empung peaks, and drifted SW on 26 October, followed by an explosion that sent incandescent material as far as 800 m away from Tompaluan crater. A second eruption produced a plume that rose 500 m above the crater. Source: Kompas.com
Puyehue-Cordon Caulle (Chile) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Puyehue-Cordon Caulle Andean Southern Volcanic Arc	Based on seismicity during 26 October-1 November, 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. During 26-29 October white plumes observed with an area web camera rose 4.5-5 km above the crater. Satellite imagery showed a plume drifting 30 km SW and W on 26 October, and diffuse ash plumes drifting E during 27-28 October. Small incandescent explosions were observed at night during 28-29 October. A plume observed in satellite imagery drifted 180 km N and NW on 29 October, and ashfall was reported in Lonquimay. On 30 October seismicity possibly indicated minor lava effusion. A mostly white plume rose 7.5 km above the crater and ash plumes observed in satellite imagery drifted 350 km NW and N. Ashfall was reported in Río Bueno (80 km WNW). Small incandescent explosions were observed at night during 30-31 October. A mostly white plume rose as high as 6.5 km above the crater on 31 October and ash plumes observed in satellite imagery drifted 270 km S and SSW. On 1 November satellite imagery showed an ash plume that drifted 300 km SE. The Alert Level remained at Red. Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
Santa Maria (Guatemala) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Santa Maria Central America Volcanic Arc	INSIVUMEH reported that during 26-27 October gas plumes from Santa María's Santiaguito lava-dome complex rose 200 m above the crater and lava flows on the SE and SW flanks generated block avalanches that were deposited into the Río Nimá II drainage. Based on analyses of satellite imagery, the Washington VAAC reported that on 26 October an ash plume drifted 16.7 km SW and then rapidly dissipated. The next day satellite imagery showed a possible ash plume and a thermal anomaly. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Sheveluch (Russia) | 26 October-1 November 2011 | Continuing ActivityCite this Report
Sheveluch Eastern Kamchatka Volcanic Arc	KVERT reported strong seismic activity at Shiveluch during 21-23 October and indicated that possible ash plumes rose to altitudes of 7.1-10.6 km (23,300-34,800 ft) a.s.l. Technical reasons prevented seismic data collection during 24-28 October. Ground-based observers noted hot avalanches in the lava dome area during 23-26 October; cloud cover prevented observations on the other days. Satellite imagery showed a large daily thermal anomaly over the lava dome and gas-and-steam plumes that drifted 170 km SE on 24 and 25 October. The Aviation Color Code remained at Orange. Based on information from Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 31 October an ash plume rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted E. Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)

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.

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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)