All times are local unless otherwise stated.

Asamayama | 15 September-21 September 2004 | New Activity / Unrest Cite this Report

Asamayama Honshu (Japan)

According to JMA, as reported by the news media, Asama erupted almost continuously for a third straight day on 16 September, causing more than 1,000 earthquakes. Incandescent fragments were ejected ~300 m from the summit and ash columns rose ~1,200 m above the crater. Late that night winds carried ash as far as central Tokyo. The frequency of the eruptions appeared to have tapered off by the afternoon of the 17th, although television footage showed gray smoke mixed with ash billowing over the mountain. By 18 September, JMA was reporting that ash plumes were still rising ~1,200 m, but only about 23 small eruptions and nearly 140 tremors had been recorded that afternoon, a significant change from the nearly consinuous activity of the previous few days. The hazard status remained at 3 on a scale of 5, meaning more small-to-medium eruptions could occur. A radar analysis conducted on 16 September confirmed that there was a lava dome in the crater, the JMA and Geographical Survey Institute reported, the first since 1973. Radar images showed a dome-shaped, layered form several dozen meters high with a radius of about 100 m in the NE part of the crater; it is an estimated 500,000 cubic meters in volume. Sources: Reuters, Associated Press, The Japan Times

Etna | 15 September-21 September 2004 | Continuing ActivityCite this Report
Etna Sicily (Italy)	News reports indicated that INGV scientists, during a helicopter survey on 15 September, noted that both of the effusive openings on the western side of the Valle del Bove had decreased in activity. The lava flow from the vent at 2,620 m a.s.l. had reached a maximum length of 1,450 m but had almost stopped, like the smaller one near Monti Centenari at 1,900 m a.s.l. Source: AGI News - Agenzia Giornalistica Italia
Fuego | 15 September-21 September 2004 | Continuing ActivityCite this Report
Fuego South-Central Guatemala	Ten explosions on 16 September sent ash columns ~400-600 m high; three ejected incandescent lava and caused block avalanches. White fumarolic plumes typically rose 300-500 m. Similar activity was observed through the 20th. Overnight on 19-20 September weak incandescence was seen from the crater. The highest plume during this period rose ~900 m. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Karymsky | 15 September-21 September 2004 | Continuing ActivityCite this Report
Karymsky Eastern Kamchatka (Russia)	Seismic activity was above background levels during 11-17 September. The number of local shallow events was 140-220 events per day. According to seismic data, several possible ash-and-gas explosions up to 2 km a.s.l. occurred on 10-11 September, and up to 2.5-6 km on 12-14 September. Karymsky remained at Concern Color Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Kilauea | 15 September-21 September 2004 | Continuing ActivityCite this Report
Kilauea Hawaiian Islands (USA)	HVO reports noted that all vents in Pu`u `O`o's crater were incandescent during this period, and glow was frequently observed from the upper reaches of the PKK flow. As of the 20th seismicity was weak at Kilauea's summit, with essentially no tremor recorded, and tremor was moderate at Pu`u `O`o. Small episodes of deflation-inflation-deflation were also recorded during 15-21 September. Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Klyuchevskoy | 15 September-21 September 2004 | Continuing ActivityCite this Report
Klyuchevskoy Central Kamchatka (Russia)	Seismic activity was at background levels this week. About 102 earthquakes (M 1.0-2.3) at a depth up to 30 km were recorded this week. A strong ash-and-gas plume rose up to 7 km a.s.l. on 15 September. Weak fumarolic activity was observed the next day. Kliuchevskoi remained at Concern Color Yellow. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Mauna Loa | 15 September-21 September 2004 | Continuing ActivityCite this Report
Mauna Loa Hawaiian Islands (USA)	No changes have been noted by HVO at Mauna Loa through 21 September. Since early July 2004, an increasing number of earthquakes has been recorded from beneath Mauna Loa. From week to week the numbers fluctuate but remain well above the earlier established norm. Through the second week of September, more than 500 earthquakes were centered beneath the summit caldera and the adjacent part of the southwest rift zone. Most of these earthquakes were quite deep, 35-50 km below the surface, and less than M 3. Inflation was continuing at the summit and has so far shown no change during the increased seismic activity. Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Pacaya | 15 September-21 September 2004 | Continuing ActivityCite this Report
Pacaya South-Central Guatemala	During 15-21 September, INSIVUMEH reported that Pacaya displayed weak glow from the MacKenney Cone and variable tremor. White plumes rose to heights 500-700 m from the central crater. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Santa Maria | 15 September-21 September 2004 | Continuing ActivityCite this Report
Santa Maria Southwestern Guatemala	Typical volcanic activity continued at Santa Maria during this report period, with explosive ash eruptions from the Caliente Dome rising up to 1 km above the vent, causing ashfall and triggering lava avalanches. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Sheveluch | 15 September-21 September 2004 | Continuing ActivityCite this Report
Sheveluch Central Kamchatka (Russia)	Unrest at the volcano continues, with a lava dome growing in the active crater and above-background levels of seismicity. On 12 September a gas-and-steam plume extended > 70 km to the ESE. According to seismic data, during 14-16 September there were four possible ash plumes up to 5-6 km a.s.l.. Video data confirmed an ash plume on the 15th. According to satellite data, 1-12-pixel thermal anomalies were registered over the lava dome on 15-16 September. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Shishaldin | 15 September-21 September 2004 | Continuing ActivityCite this Report
Shishaldin Fox Islands (USA)	Low-level seismic tremor continued to be recorded at Shishaldin during 10-17 September. This level of activity is similar to that observed over the past several months. Shishaldin remained at Concern Color Code Yellow. Source: US Geological Survey Alaska Volcano Observatory (AVO)
Soufriere Hills | 15 September-21 September 2004 | Continuing ActivityCite this Report
Soufriere Hills Montserrat	Activity at Soufrière Hills during 10-17 September was slightly elevated. The seismic network recorded one rockfall, one long-period, and 14 hybrid earthquakes. The weekly average for daily sulfur dioxide emissions was 180 metric tons. Unusual winds brought the volcanic plume across inhabited areas from time to time, causing people to experience its characteristic sulfurous smell. Mudflows, due to heavy rain, were recorded on 14 and 16 September. Source: Montserrat Volcano Observatory (MVO)
Spurr | 15 September-21 September 2004 | Continuing ActivityCite this Report
Spurr Alaska Peninsula	Elevated levels of seismicity continue to be recorded, but have not changed significantly from that observed in the past few weeks. During the week ending on 17 September there were about 85 earthquakes located within 30 km of the summit with an average of approximately 12 per day. Observations of the summit during AVO overflights showed no major changes. Spurr remained at Concern Color Code Yellow. Source: US Geological Survey Alaska Volcano Observatory (AVO)
Tungurahua | 15 September-21 September 2004 | Continuing ActivityCite this Report
Tungurahua Ecuador	Throughout this period, Tungurahua exhibited weak gas emissions and crater glow. Tremor and long-period events were associated with steam emissions. The IG daily report on 20 September noted that some explosions generated plumes with ash, casuing ashfall in Bilbao and Pondoa. Columns with moderate ash content reached 1 km above the vent. Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)
Veniaminof | 15 September-21 September 2004 | Continuing ActivityCite this Report
Veniaminof Alaska Peninsula, Alaska	Low-level seismic tremor and intermittent tremor bursts continue to be recorded at Veniaminof. Tremor episodes likely represent low-level ash and steam emissions similar to those observed over the past four months. Minor emissions of volcanic ash and steam were occasionally observed using web camera images during times of clear weather. Veniaminof remained at Concern Color Code Yellow. Source: US Geological Survey Alaska Volcano Observatory (AVO)

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)