All times are local unless otherwise stated.

Erta Ale | 28 September-4 October 2005 | New Activity / UnrestCite this Report
Erta Ale Ethiopia	A group of scientists assessed the visible changes at Erta Ale on 26 September after activity began around 24 September. In comparison to observations made in November 2004, they found that the southern main crater/pit had widened significantly, with portions of the previous crater walls having collapsed into the lava lake. A new cone-shaped construct had grown within the southern main crater where there had been a platform. A lava lake occupied the entire width of the inner crater/pit. In the northern crater/pit, there was a solidified lava bulge and abundant "smoking" along the crater walls. No incandescent lava was visible in the pit. Based on descriptions by local residents of seeing "red and glowing light shooting and rising into the air above the volcano," the scientists believe that a Strombolian eruption probably occurred, emitting a significant volume of fresh magma within, and possibly out of, the pit. According to news reports, about 50,000 nomads in Ethiopia's Afar region were displaced after the eruption. Sources: Gezahegn Yirgu, Department of Earth Sciences, Addis Ababa University, Agence France-Presse (AFP)
Santa Ana | 28 September-4 October 2005 | New Activity / UnrestCite this Report
Santa Ana Western El Salvador	SNET reported that a sudden eruption at Santa Ana (also called Ilamatepec) on 1 October around 0820 produced an ash-and-gas plume to a height of ~10 km above the volcano (or 40,600 ft a.s.l.). According to the Washington VAAC, ash was visible on satellite imagery at a height of ~14 km (46,000 ft) a.s.l. Ash fell in towns W of the volcano, including in Naranjos, Nahuizalco, Juayúa, Ahuachapán, and La Hachadura. Volcanic blocks up to a meter in diameter fell as far as 2 km S of the volcano's crater. Lahar deposits were seen SE of the volcano. The Alert Level within a 4-km radius around the volcano's central crater was raised to Red, the highest level. According to news reports, two people were killed by landslides (possibly caused by heavy rain in the area) in the town of Palo Campana, and thousands of residents near the volcano were evacuated. As many as 1,400 hectares of crops were damaged by ash. Prior to the eruption, significant changes in seismicity were not noted. On 3 October, after the eruption, seismicity fluctuated and small explosions occasionally occurred. Earthquakes associated with explosions were recorded. In addition, there was a decrease in the amount of sulfur dioxide emitted from the volcano. SNET noted that eruptive activity could continue at the volcano. Sources: Associated Press, Servicio Nacional de Estudios Territoriales (SNET), Reuters, ReliefWeb

Barren Island | 28 September-4 October 2005 | Continuing ActivityCite this Report
Barren Island Andaman Islands (India)	Low-level plumes from Barren Island were visible on satellite imagery on 28 September and 2 October. The current eruption of Barren Island began on 28 May 2005. Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Cayambe | 28 September-4 October 2005 | Continuing ActivityCite this Report
Cayambe Ecuador	A cluster of earthquakes that had been recorded at Cayambe since 16 September, with about 300 small earthquakes occurring during 16-18 September, decreased in number significantly after 19 September. During 19-25 September, an average of 5.3 earthquakes occurred daily. Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
Colima | 28 September-4 October 2005 | Continuing ActivityCite this Report
Colima Mexico	During 28 September to 3 October, several small explosions occurred at Colima. Based on information from the Mexico City MWO, the Washington VAAC reported that a plume was emitted on 28 September that rose to a height of ~6.1 km (20,000 ft) a.s.l. and drifted NNW. Sources: Washington Volcanic Ash Advisory Center (VAAC), Centro Universitario de Estudios e Investigaciones de Vulcanologia - Universidad de Colima
Dukono | 28 September-4 October 2005 | Continuing ActivityCite this Report
Dukono Halmahera	A thin low-level plume from Dukono was visible on satellite imagery on 28 September extending NE. Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Kilauea | 28 September-4 October 2005 | Continuing ActivityCite this Report
Kilauea Hawaiian Islands (USA)	During 28 September- 2 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. During the report period, 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)
Manam | 28 September-4 October 2005 | Continuing ActivityCite this Report
Manam Northeast of New Guinea	On 1 October, a pilot observed ash from Manam below a height of ~3 km (10,000 ft) a.s.l. extending NW. Ash was not visible on satellite imagery. Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Reventador | 28 September-4 October 2005 | Continuing ActivityCite this Report
Reventador Ecuador	During 19-25 September, several small explosions occurred at Reventador. An explosion on 20 September produced an ash plume to a height of ~5.8 m (19,000 ft) a.s.l. Small amounts of ash fell in the towns of El Chaco, San Francisco de Borja, and Baeza. During the report week, there was a reduction in the number of earthquakes at the volcano. Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
Sheveluch | 28 September-4 October 2005 | Continuing ActivityCite this Report
Sheveluch Central Kamchatka (Russia)	Growth of Shiveluch's lava dome and heightened seismicity continued at the volcano during 23-30 September. Weak gas-and-steam plumes, thermal anomalies at the lava dome, and new pyroclastic-flow deposits, were noted during the report week. Shiveluch remained at Concern Color Code Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Soufriere Hills | 28 September-4 October 2005 | Continuing ActivityCite this Report
Soufriere Hills Montserrat	Volcanic and seismic activity at Soufrière Hills remained at elevated levels during 23-30 September. Slow lava-dome growth continued at the volcano. The daily sulfur-dioxide flux averaged 950 metric tons per day (t/d), above the long-term eruption average of 500 t/d. Source: Montserrat Volcano Observatory (MVO)
St. Helens | 28 September-4 October 2005 | Continuing ActivityCite this Report
St. Helens Washington	Growth of the new lava dome inside the crater of Mount St. Helens continued during 28 September to 4 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 and the level of eruptive activity remained similar to previous weeks. Reanalysis of late September time-series photographs of the active part of the new lava dome indicated that points on the dome moved northwestward and upward at about 5.5 meters per day as extrusion continued. St Helens remained at Volcano Advisory (Alert Level 2); aviation color code Orange. Source: US Geological Survey Cascades Volcano Observatory (CVO)
Tungurahua | 28 September-4 October 2005 | Continuing ActivityCite this Report
Tungurahua Ecuador	During 28 September to 3 October, volcanic activity at Tungurahua remained at low levels with small emissions of steam, gas, and variable ash content. A pilot reported an ash plume on 29 September at a height of ~6.1 km (20,000 ft) a.s.l. Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
Veniaminof | 28 September-4 October 2005 | Continuing ActivityCite this Report
Veniaminof Alaska Peninsula, Alaska	AVO decreased the Concern Color Code at Veniaminof from Yellow to Green (the lowest level) on 28 September after seismicity at the volcano had been at background levels for over a week and there was no evidence to suggest that minor ash explosions were continuing. Source: US Geological Survey Alaska Volcano Observatory (AVO)

Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 18,793 individual reports over 1,160 weeks (average of 16 per week) on 329 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)