All times are local unless otherwise stated.

Anatahan (United States) | 21 May-27 May 2003 | New Activity / Unrest Cite this Report

Anatahan Mariana Volcanic Arc

Volcanic activity that began at Anatahan on 10 May continued during 21-27 May. On 21 May an ash plume was visible on satellite imagery at a height of about 4.9 km a.s.l. drifting W. Around 23 May, typhoon Chan-hom caused a shift in the prevailing wind direction near Anatahan and ash was transported S over the islands of Saipan, Tinian, Rota, and Guam. Due to the ash, airlines cancelled several flights to and from Saipan and Guam international airports. In Saipan and Guam an ash advisory, and a volcanic haze advisory, respectively, were issued on the 23rd stating that residents should be cautious of lower air quality due to the plume of ash, SO2, and other gases over the islands that morning. By 24 May the plume had drifted away from the islands. According to the Washington VAAC, satellite imagery on 24 May at 1413 showed the ash plume at a height around 5.2 km a.s.l. caught up in the cyclonic circulation of the typhoon moving S, then SE. By 27 May the ash cloud was around 3 km a.s.l. and drifting E. Sources: GuamPDN - Pacific Daily News, Saipan Tribune, Washington Volcanic Ash Advisory Center (VAAC), Saipan Tribune

Chikurachki (Russia) | 21 May-27 May 2003 | Continuing ActivityCite this Report
Chikurachki Kuril Volcanic Arc	The eruption that began at Chikurachki on 18 April continued during 16-23 May. On 17 and 18 May ash-rich plumes were visible on satellite imagery drifting SW and NE, respectively. Chikurachki remained at Concern Color Code Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Karangetang (Indonesia) | 21 May-27 May 2003 | Continuing ActivityCite this Report
Karangetang Sangihe Volcanic Arc	A reduction in volcanic activity at Karangetang during 12-18 May led VSI to reduce the Alert Level from 3 to 2. Activity during the week consisted of low-level ash clouds rising above Karangetang's South crater, incandescence extending 25 m above the crater, and incandescent avalanches traveling toward Kali Batang to runout distances of 750-1,000 m. In addition, there was a decrease in the number of multiphase earthquakes compared to the previous week. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Karymsky (Russia) | 21 May-27 May 2003 | Continuing ActivityCite this Report
Karymsky Eastern Kamchatka Volcanic Arc	Intermittent explosions occurred at Karymsky during 16-23 May. Seismicity was above background levels, with 150 to 320 shallow events occurring per day during 18-21 May. Seismic data indicated that ash-and-gas explosions reached heights up to 1 km above the crater, and gas blowouts and hot avalanches possibly occurred. On 18 May ash deposits were seen on snow on the volcano's S and SE flanks. Karymsky remained at Concern Color Code Yellow. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Kilauea (United States) | 21 May-27 May 2003 | Continuing ActivityCite this Report
Kilauea Hawaiian-Emperor Hotspot Volcano Group	During 21-26 May, surface lava flows were visible on Kilauea's coastal flat and the Pulama Pali fault scarp. Small amounts of lava began to flow into the sea on 21 May. Generally, seismicity was at normal levels, with little or no volcanic tremor occurring at Kilauea's summit. A swarm of small, low-frequency earthquakes occurred during 23 May until at least 26 May. The swarm occurred at shallow depths below the caldera floor and was the second such swarm in a 10-day period. No significant deformation occurred during the report period. Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Klyuchevskoy (Russia) | 21 May-27 May 2003 | Continuing ActivityCite this Report
Klyuchevskoy Eastern Kamchatka Volcanic Arc	Volcanic unrest continued at Kliuchevskoi during 16-23 May. Seismicity was above background levels, with five M 2-2.1 earthquakes occurring at depths around 30 km during 15-21 May. Continuous spasmodic volcanic tremor occurred during the report period. Gas-and-steam plumes rose above the crater to low levels. On 18 May during 0000-0500, incandescence was visible above the volcano's crater from the town of Klyuchi. This is the first such observation since 1994. Thermal anomalies were visible on satellite imagery during 15-22 May. On 17 May ash deposits were visible on the volcano's E and SE flanks. Kliuchevskoi remained at Concern Color Code Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Semeru (Indonesia) | 21 May-27 May 2003 | Continuing ActivityCite this Report
Semeru Sunda Volcanic Arc	Volcanic and seismic activity at Semeru continued at relatively high levels during 12-18 May. Several small ash explosions rose to low levels above the summit. Seismicity was dominated by 730 explosion events. Semeru remained at Alert Level 2 (on a scale of 1-4). Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Sheveluch (Russia) | 21 May-27 May 2003 | Continuing ActivityCite this Report
Sheveluch Eastern Kamchatka Volcanic Arc	Seismicity continued to be above background levels at Shiveluch during 16-23 May. Weak, shallow earthquakes were recorded and seismic data indicated that an ash-and-gas explosion reached a height of about 4 km above the lava dome. Incandescent lava avalanches may have occurred on 17 May. Intermittent, spasmodic, volcanic tremor was recorded during 14-22 May. Thermal anomalies were visible on satellite imagery. Shiveluch remained at Concern Color Code Yellow. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Soufriere Hills (United Kingdom) | 21 May-27 May 2003 | Continuing ActivityCite this Report
Soufriere Hills Lesser Antilles Volcanic Arc	Volcanic activity at Soufrière Hills was generally at high levels during 16-23 May, although there was a slight decrease in intensity on 19 and 20 May. Most activity was focused on the lava dome's NE flank, producing rockfalls and numerous pyroclastic flows along the northern side of Tar River Valley. During the last 3 days of the report period, activity increased on the N flank, with pyroclastic flows traveling into the top of Farrell's Plain and entering the top of Tyre's and Tuitt's ghauts. Pulses of vigorous ash venting were observed from the dome's summit. Intense glow was seen on the summit and NE flank on the evenings of 20 and 21 May. Low-level ash plumes were sometimes visible on satellite imagery. Sources: Montserrat Volcano Observatory (MVO), Washington 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.

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 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)