All times are local unless otherwise stated.

Rinjani (Indonesia) | 6 October-12 October 2004 | New Activity / Unrest Cite this Report
Rinjani Sunda Volcanic Arc	An eruption occurred at Rinjani on 1 October at 1730 following an increase in seismicity that began on 5 September (0-7 earthquakes occurred per day). DVGHM raised the Alert Level to 3 (on a scale of 1-4) or Orange. During 2-4 October, explosions produced thick gray ash plumes to heights of ~300-800 m above the post-caldera cone, Barujari. The explosions occurred on the NE slope of Barujari cone every 5 to 160 minutes. Seismicity was dominated by explosion earthquakes. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
St. Helens (United States) | 6 October-12 October 2004 | New Activity / Unrest Cite this Report
St. Helens High Cascades Volcanic Arc	Following a steam-and-ash emission at St. Helens on 5 October, seismicity dropped to low levels and CVO reduced the warning from Volcano Alert (Alert Level 3: aviation color code Red), to Volcano Advisory (Alert Level 2: aviation color code Orange). During 6-12 October, seismicity was at low-to-moderate levels, with the highest magnitude earthquakes (M 2.4) occurring at a rate of one every 2 minutes on 8 October. On 6 October only weak steam puffs were emitted from the volcano and CVO scientists confirmed that the top of the area of intense uplift was at or slightly above the highest point on the lava dome, which suggested that some uplift occurred during the period of low seismicity. Scientists also confirmed that small lahars spilled out of the crater and onto the Pumice Plain during a rainstorm the evening of 5 October. Lahars traveled a short distance toward Spirit Lake and the North Fork Toutle River. CVO received reports that a light dusting of ash from the emission on 5 October affected the eastern part of Mount Rainier National Park, ~110 km NNE of St. Helens. A new steam vent opened during the evening of 6 October, joining two that had been present for several days. Measurements from recent photographs and LIDAR (LIght Detection And Ranging) showed that as of 7 October the intensely deformed and uplifted area on the S side of the 1980-86 lava dome was ~400 m (N-S) by ~490 m (E-W) with a maximum uplift of about 90-120 m. Additional analysis revealed that the total volume change represented by the deformation between late September and 6 October was ~16 million cubic meters. The average rate of change was ~2 million cubic meters per day. On 11 October, thermal imaging of the western part of the uplifting area revealed temperatures of 500 to 600 degrees C on a large pinkish-gray fin of rock and in nearby fumaroles and cracks. These observations are consistent with new lava having reached the surface of the uplift. A gas-sensing flight on 11 October measured fluxes of sulfur dioxide and carbon dioxide that were similar to, or slightly smaller than, those measured on 7 October. CVO reported on 13 October, "As a result of the intense unrest of the past two and one-half weeks and recent observations, we infer that magma is at a very shallow level and is extruding onto the surface. Incandescence from hot rock or gases reflects off steam clouds and is visible from north of the volcano. During times of unrest, Mount St. Helens and similar volcanoes elsewhere typically go through episodic changes in level of unrest over periods of days to weeks, or even months. Such changes are in part driven by variations in the rate of magma movement. We expect fluctuations in the level of unrest to continue during coming days. Escalation in the degree of unrest could occur suddenly or with very little warning. There may be little time to raise the alert level before a hazardous event occurs." Source: US Geological Survey Cascades Volcano Observatory (CVO)

Asamayama (Japan) | 6 October-12 October 2004 | Continuing ActivityCite this Report
Asamayama Northeast Japan Volcanic Arc	Based on information from JMA, the Tokyo VAAC reported that an eruption at Asama at 2310 on 10 October produced a plume to an unknown height. Source: Tokyo Volcanic Ash Advisory Center (VAAC)
Colima (Mexico) | 6 October-12 October 2004 | Continuing ActivityCite this Report
Colima Trans-Mexican Volcanic Belt	During 6-11 October, block-lava flows continued to travel down Colima's N, NW, W, and S flanks as they have since 30 September. On 6 October, the block-lava flows on the N flank reached a length of ~600 m and a width of 150 m, and on the WNW flank the block-lava reached a length of ~250 m. About 32 explosions occurred that day, producing plumes to ~400 m above the volcano. On 11 October, a block-lava flow on the N flank reached a length of ~900 m and a width of ~150 m, and on the WNW flank the block-lava flow reached a length of ~300 m and a width of ~200 m. About 27 small explosions again produced plumes to a height of ~400 m above the volcano. During the report period, block-and-ash flows spilling from the fronts of the advancing block-lava flows reached ~ 2 km from the summit. Source: Centro Universitario de Estudios Vulcanológicos (CUEV) - Universidad de Colima
Etna (Italy) | 6 October-12 October 2004 | Continuing ActivityCite this Report
Etna Sicily Volcanic Province	According the Etna Volcan Sicilen website, lava emission continued at Etna during 6-11 October from vents around 2,620 m and 2,350 m elevations. Lava emission from the 2,620-m-elevation vent flowed in several arms down Valle del Bove. At the 2,350-m-elevation vent, lava flowed in tunnels for tens of meters. Source: Etna Volcan Sicilien (Charles Rivière)
Fuego (Guatemala) | 6 October-12 October 2004 | Continuing ActivityCite this Report
Fuego Central America Volcanic Arc	During the evening of 9 October, a narrow lava flow traveled ~800 m down Fuego's SSW flank towards the head of the Taniluyá River. A small sustained lava fountain reached ~75 m above the volcano during the evening of 10 October. On 12 October, a narrow lava flow traveled ~400 m from an area about 20 m below the S edge of the crater. Small avalanches occurred from the lava-flow fronts. Six explosions produced plumes to ~600 m above the volcano's summit. A small lahar traveled towards the Zanjón Barranca Seca Ravine. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Galeras (Colombia) | 6 October-12 October 2004 | Continuing ActivityCite this Report
Galeras Andean Northern Volcanic Arc	During 8-11 October, emissions of gas and fine ash continued at Galeras. Plumes rose to a maximum height of ~1.5 km above the volcano. Small-amplitude tremor associated with gas-and-ash emissions was recorded. Source: Servicio Geológico Colombiano (SGC)
Kilauea (United States) | 6 October-12 October 2004 | Continuing ActivityCite this Report
Kilauea Hawaiian-Emperor Hotspot Volcano Group	On 11 and 12 October, patches of incandescent lava were visible on the PKK lava flow on the Pulama Pali fault scarp and all vents in the crater of Pu`u `O`o were incandescent. Tremor was at moderate levels at Pu`u `O`o. Essentially no tremor was recorded at Kilauea's summit. A M 4.0 earthquake occurred at Kilauea's summit at a depth of ~32 km on 11 October at 1030 that affected tilt meters. Taking earthquake- and rainfall-induced tilts into account, the volcanic tilt was minor. Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Mauna Loa (United States) | 6 October-12 October 2004 | Continuing ActivityCite this Report
Mauna Loa Hawaiian-Emperor Hotspot Volcano Group	According to HVO, since early July 2004 an increased number of earthquakes had been recorded from beneath Mauna Loa. From week to week, the numbers fluctuated but remained well above the norm. Through September, more than 580 earthquakes were centered beneath Mauna Loa's summit caldera and the adjacent part of the southwest rift zone. Most of these earthquakes were quite deep, from 35 to 50 km below the ground surface and small, less than M 3. They were "long-period" (LP) earthquakes, which means that their signals gradually rise out of the background rather than appearing abruptly. Such a concentrated number of deep LP earthquakes from this part of Mauna Loa is unprecedented, at least in the modern earthquake record dating back to the 1960s. During about 4-11 October, however, only 23 earthquakes were located under the summit. Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Santa Maria (Guatemala) | 6 October-12 October 2004 | Continuing ActivityCite this Report
Santa Maria Central America Volcanic Arc	On 11 October, a partial lava-dome collapse to the SW at Santa Maria's Santiaguito lava-dome complex produced a pyroclastic flow that traveled toward the Nimá Segundo River. An ash cloud formed that rose to a height of ~500 m and covered most of the dome complex. The collapse was preceded by an explosion that produced an ash-and-gas cloud to ~1.5 km above the volcano. Small explosions on 12 October produced small lava-dome collapses to the SW that generated avalanches of lava blocks and ash. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Soufriere Hills (United Kingdom) | 6 October-12 October 2004 | Continuing ActivityCite this Report
Soufriere Hills Lesser Antilles Volcanic Arc	Volcanic and seismic activity at Soufrière Hills remained at slightly elevated levels during 1-8 October. The seismic network recorded one rockfall, two long-period earthquakes, and eight hybrid earthquakes. The sulfur-dioxide flux ranged between 187 and 1,144 metric tons per day, with a weekly average of 462 metric tons per day. Source: Montserrat Volcano Observatory (MVO)
Tungurahua (Ecuador) | 6 October-12 October 2004 | Continuing ActivityCite this Report
Tungurahua Andean Northern Volcanic Arc	Volcanic and seismic activity at Tungurahua during 11-12 October were at relatively low levels, characterized by a few long-period earthquakes and small explosions. Emissions mainly consisted of steam and gas, with small amounts of ash. Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 20,322 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.

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)