All times are local unless otherwise stated.

Sierra Negra | 26 October-1 November 2005 | New Activity / Unrest Cite this Report

Sierra Negra Isla Isabela (Galapagos)

According to IG, an eruption began at Sierra Negra on the S end of Isabela Island on 22 October at 1730 when an explosion was heard by many people in the town of Villamil, 20 km SE of the volcano. The eruption was preceded by a seismic event on 22 October at 1438, and by earthquakes on 19 October and 2 weeks earlier. The Washington VAAC recorded an ash cloud on satellite imagery at 1745 at a height of ~15.2 km (50,000 ft) a.s.l. moving SW, and a very large hotspot. The ash cloud may have reached a height of 20 km (65,600 ft) a.s.l. Extensive lava fountains were seen rising to heights of 200-300 m along a segment of the Sierra Negra rim. Incandescent lava flowed several kilometers down the outer NW flank of the volcano's edifice and tourists reported seeing two lava flows descending the N flank. The exact orientation of flows on the volcano's flanks was not clear from early reports. Scientists did not see active lava flows in this area or evidence of flows entering the sea during an overflight on 23 October. During a visit to Sierra Negra on 23 October, scientists saw that the eruption originated from four adjacent craters aligned along a 500-m-long fracture at the base of the inner wall of the volcano's caldera in the NE sector. Lava traveled from four principal vents southwards with exceptional force, volume, and speed downslope in several main channels. Based on observations, the main lava river traveled nearly 20 m/sec as it left its source vents. Two vents mainly supplied lava to the many lava rivers flowing southward over the northern caldera bench and then down onto the caldera floor. The feeding fracture apparently extended westward along the inner wall, but then climbed up onto the caldera rim itself where its trace was not obvious. However, small vents with fountaining and incandescent lava were observed on the rim along this general fracture system, implying that the active fracture extended for about 2 km W of the main vents. By 23 October around 1530, the lava formed one large flow that was 1-1.5 km wide and had progressed ~7 km southeastward along the base of the eastern interior wall of the caldera, then westward along the southern wall reaching a point almost halfway across the caldera. The volume of lava ejected at this time was estimated at 25 million cubic meters. On 26 October, there were reports that lava was no longer emitted from one of the four principal vents. No populated areas on the island were threatened by the eruption. Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

Colima | 26 October-1 November 2005 | Continuing ActivityCite this Report
Colima Mexico	During 26-31 October, several small eruptions occurred at Colima, with ash plumes rising as high as ~6.1 km (20,000 ft) a.s.l. on 27 October. Sources: Centro Universitario de Estudios Vulcanológicos (CUEV) - Universidad de Colima, Washington Volcanic Ash Advisory Center (VAAC)
Dukono | 26 October-1 November 2005 | Continuing ActivityCite this Report
Dukono Halmahera	An ash plume from Dukono was visible on satellite imagery on 27 October, extending NNW. Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Karymsky | 26 October-1 November 2005 | Continuing ActivityCite this Report
Karymsky Eastern Kamchatka (Russia)	During 21-28 October, seismicity at Karymsky was above background levels. Based on interpretations of seismic data, five ash-and-gas plumes may have reached heights of 2.5-3.5 km (8,200-11,500 ft) a.s.l. on several days. A thermal anomaly at the volcano was visible on satellite imagery. Karymsky remained at Concern Color Code Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Kilauea | 26 October-1 November 2005 | Continuing ActivityCite this Report
Kilauea Hawaiian Islands (USA)	During 26-31 October, lava from Kilauea continued to enter the sea at the East Lae`apuki area, and surface lava flows were visible on the Pulama pali fault scarp. Background volcanic tremor was near normal levels at Kilauea's summit. Volcanic tremor reached moderate levels at Pu`u `O`o. Small amounts of inflation and deflation occurred at the volcano during the report period. Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Krummel-Garbuna-Welcker | 26 October-1 November 2005 | Continuing ActivityCite this Report
Krummel-Garbuna-Welcker New Britain (Papua New Guinea)	Based on information from RVO and satellite imagery, the Darwin VAAC reported that on 25 October a pale gray ash cloud rose a few hundred meters above the summit of Garbuna, but no eruption was noted. Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Langila | 26 October-1 November 2005 | Continuing ActivityCite this Report
Langila New Britain (Papua New Guinea)	On 29 October, a plume from Langila was visible on satellite imagery at a height of ~2.7 km (9,000 ft) a.s.l. Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Manam | 26 October-1 November 2005 | Continuing ActivityCite this Report
Manam Northeast of New Guinea	During 29-30 October, low-level eruptive activity continued at Manam with plumes visible on satellite imagery extending NW. Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Nyamulagira | 26 October-1 November 2005 | Continuing ActivityCite this Report
Nyamulagira DR Congo	Beginning on 23 October, GVO recorded heightened seismic activity along the East African Rift and around the Virunga volcanoes when a swarm of long-period earthquakes occurred N of Nyamuragira. More than 140 events were recorded at a station 19 km E of the volcano. On 27 October at 1500, another swarm of long-period earthquakes began beneath the same area. More than 300 events were recorded until at least 28 October. At 2010, a M 4.5 tectonic earthquake occurred N of Lake Tanganika, which was followed by several aftershocks. GVO noted that this activity reinforces the likelihood of an eruption in the near future, but volcanic activity would not pose a threat to inhabited areas. The Alert Level for the nearby city of Goma remained at Yellow. Source: Observatoire Volcanologique de Goma (OVG)
Nyiragongo | 26 October-1 November 2005 | Continuing ActivityCite this Report
Nyiragongo DR Congo	GVO reported that as of 28 October Nyiragongo remained very active, but stable. There was a permanently active large lava lake in the volcano's crater. A gas plume was emitted from the volcano and incandescence was visible at night several tens of kilometers from Nyiragongo. The Alert Level for the nearby city of Goma remained at Yellow. Source: Observatoire Volcanologique de Goma (OVG)
Sangay | 26 October-1 November 2005 | Continuing ActivityCite this Report
Sangay Ecuador	Based on information from IG, the Washington VAAC reported that ash was seen over Sangay on 26 October at 0758. No ash was visible on satellite imagery. Source: Washington Volcanic Ash Advisory Center (VAAC)
Santa Ana | 26 October-1 November 2005 | Continuing ActivityCite this Report
Santa Ana Western El Salvador	During 30-31 October, seismicity increased at Santa Ana. Volcanic activity appeared to slightly increase starting on 28 October. Sulfur-dioxide emission rates during 28 and 29 October averaged 257 metric tons per day. The Alert Level within a 5-km radius around the volcano's central crater was at Red, the highest level. Source: Servicio Nacional de Estudios Territoriales (SNET)
Santa Maria | 26 October-1 November 2005 | Continuing ActivityCite this Report
Santa Maria Southwestern Guatemala	During 26-31 October, small-to-moderate explosions occurred at Santa María's Santiaguito lava-dome complex. Plumes were produced that rose to a maximum height of ~4.9 km (16,000 ft) a.s.l. on the 28th. Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center (VAAC)
Sheveluch | 26 October-1 November 2005 | Continuing ActivityCite this Report
Sheveluch Central Kamchatka (Russia)	The growth of Shiveluch's lava dome continued during 21-28 October. Weak shallow earthquakes, hot avalanches, and low-intensity fumarolic activity occurred at the volcano during the week. On 22 and 24 October, incandescence was visible at the lava dome. A weak ash-and-gas plume extending E was observed on 22 October. Shiveluch remained at Concern Color Code Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Soufriere Hills | 26 October-1 November 2005 | Continuing ActivityCite this Report
Soufriere Hills Montserrat	Volcanic and seismic activity at Soufrière Hills remained at elevated levels during 21-28 October. On 26 October around 2400, a pyroclastic flow traveled ~2 km down the volcano's NE flank. The pyroclastic flow was confined to the Tar River Valley. During the report week, the lava dome continued to grow and incandescence was visible at night. The sulfur-dioxide flux averaged 420 metric tons per day (t/d), below the long-term eruption average of 500 t/d. The hydrogen-chloride to sulfur-dioxide ratio measured on 26 October was at 1.3. According to the Washington VAAC, a pilot reported observing a thin layer of ash at a height of ~2.4 km (8,000 ft) a.s.l. above St. Croix on 28 October at 1010. Sources: Montserrat Volcano Observatory (MVO), Washington Volcanic Ash Advisory Center (VAAC)
St. Helens | 26 October-1 November 2005 | Continuing ActivityCite this Report
St. Helens Washington	Growth of the new lava dome inside the crater of Mount St. Helens continued during 26-31 October, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash. There were no significant changes in seismicity or deformation during the report period. Heavy rain at the volcano increased stream flows and triggered a small debris flow on 31 October that did not extend very far down the fan at the crater mouth. St Helens remained at Volcano Advisory (Alert Level 2); aviation color code Orange. Source: US Geological Survey Cascades Volcano Observatory (CVO)
Tanaga | 26 October-1 November 2005 | Continuing ActivityCite this Report
Tanaga Andreanof Islands (USA)	Elevated seismicity below young volcanic vents on Tanaga Island continued during 21-28 October. Beginning on 24 October, AVO observed weak, nearly continuous volcanic tremor in the vicinity of Takawangha volcano of the Tanaga volcano cluster. This was the first time that tremor of this sort had been observed in the volcanic cluster since the seismic network was installed in 2003. The daily number of small earthquakes continued to diminish from its peak in early October, but stayed above background levels. Tanaga remained at Concern Color Code Yellow. Source: US Geological Survey Alaska Volcano Observatory (AVO)
Tungurahua | 26 October-1 November 2005 | Continuing ActivityCite this Report
Tungurahua Ecuador	During 26-31 October, volcanic activity at Tungurahua remained at low levels with small emissions of steam, gas, and low ash content. On 30 October, clouds with low ash content reached heights of 500-1,000 m above the volcano's crater (or 18,100-19,750 ft a.s.l.) and drifted W. Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 20,019 individual reports over 1,216 weeks (average of 16 per week) on 332 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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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)