All times are local unless otherwise stated.

Ambae (Vanuatu) | 20 July-26 July 2011 | New Activity / Unrest Cite this Report
Ambae Vanuatu Volcanic Arc	Based on analysis of data collected by the Vanuatu Meteorology and Geohazards Department (VMGD), the Vanuatu Geohazards Observatory reported that a small series of explosions from Aoba occurred on 10 July. Photos showed that the volcano was quiet on 12 July, although ongoing earthquakes were detected. On 18 July the Vanuatu Volcano Alert Level (VVAL) remained at 1 (on a scale of 0-4). Source: Vanuatu Meteorology and Geohazards Department (VMGD)
Ambrym (Vanuatu) | 20 July-26 July 2011 | New Activity / Unrest Cite this Report
Ambrym Vanuatu Volcanic Arc	Based on pilot observations and analyses of satellite imagery, the Wellington VAAC reported that on 19 July an ash plume from Ambrym rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 185 km NW. Source: Wellington Volcanic Ash Advisory Center (VAAC)
Cleveland (United States) | 20 July-26 July 2011 | New Activity / Unrest Cite this Report
Cleveland Aleutian Ridge Volcanic Arc	AVO reported that on 20 July the Volcano Alert Level for Cleveland was raised to Advisory, and the Aviation Color Code was raised to Yellow, due to thermal anomalies visible in satellite imagery during 19-20 and 22 July. Cloud cover prevented observations during 21 and 23-26 July. No current seismic information was available because Cleveland does not have a real-time seismic network. Source: US Geological Survey Alaska Volcano Observatory (AVO)
Etna (Italy) | 20 July-26 July 2011 | New Activity / Unrest Cite this Report
Etna Sicily Volcanic Province	Sezione di Catania - Osservatorio Etneo reported that the seventh eruption of Etna in 2011 occurred from the active crater on the E flank of the SE Crater cone. On 24 July vigorous Strombolian activity started within the crater, gradually increased through the night, and culminated on 25 July. Strombolian activity gradually turned into a pulsating lava fountain, accompanied by increasingly voluminous ash emissions. The fountain fluctuated between 250 and 300 m above the crater with a few jets rising 350 m. Lava flowed through a breach on the E crater rim and divided into multiple parallel flows that reached the base of the steep W slope of the Valle del Bove near Monte Centenari. Plumes drifted E causing ashfall between the villages of Fornazzo and Milo on the flank (10 km E), and the Ionian coast near Riposto (18 km E). The final phase of the eruption was characterized by a series of violent explosions that produced loud detonations heard in the E and SE sectors of the volcano. Source: Sezione di Catania - Osservatorio Etneo (INGV)
Lokon-Empung (Indonesia) | 20 July-26 July 2011 | New Activity / Unrest Cite this Report
Lokon-Empung Sangihe Volcanic Arc	CVGHM reported that during 20-21 July seismicity and visual observations of Tompaluan crater, in the saddle between the Lokon-Empung peaks, indicated that activity continued to be high. On 20 July plumes rose 100-500 m above the crater, and during 21-24 July white plumes rose 100-300 m above the crater. CVGHM noted that, since the eruption on 18 July, most data showed a decline in activity and therefore on 24 July the Alert Level was lowered to 3 (on a scale of 1-4). Residents and tourists were not permitted within a 3-km radius of the crater. A news article stated that on that same day about 5,000 residents that had evacuated returned home, and about 200 people remained in shelters. Sources: Straits Times, Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Soputan (Indonesia) | 20 July-26 July 2011 | New Activity / Unrest Cite this Report
Soputan Sangihe Volcanic Arc	CVGHM reported that on 3 July an explosion of incandescent material from Soputan was followed by a 6-km-high ash plume and a pyroclastic flow that traveled as far as 4 km W. Later that day a dense white plume rose 50 m above the crater. On 20 July CVGHM noted that since 4 July seismicity had decreased and only diffuse white plumes rose 75 m above the crater until 18 July. The Alert Level was lowered to 2 (on a scale of 1-4) on 19 July. Visitors and residents were prohibited from going within a 4-km radius of the crater. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Aira (Japan) | 20 July-26 July 2011 | Continuing ActivityCite this Report
Aira Ryukyu Volcanic Arc	Based on information from JMA, the Tokyo VAAC reported that during 20-22 and 25 July plumes from Sakura-jima rose to altitudes of 1.2-3 km (4,000-10,000 ft) a.s.l. Plumes occasionally drifted S, SE, and ENE. On 20, 22, and 26 July, pilots observed ash plumes that rose to altitudes of 1.8-2.7 km (6,000-9,000 ft) a.s.l. Source: Tokyo Volcanic Ash Advisory Center (VAAC)
Karymsky (Russia) | 20 July-26 July 2011 | Continuing ActivityCite this Report
Karymsky Eastern Kamchatka Volcanic Arc	KVERT reported that during 15-22 July moderate seismic activity continued at Karymsky and possible ash plumes rose to an altitude of 4 km (13,000 ft) a.s.l. A thermal anomaly on the volcano was detected by satellite during 14, 16, and 18-21 July. The Aviation Color Code remained at Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Kilauea (United States) | 20 July-26 July 2011 | Continuing ActivityCite this Report
Kilauea Hawaiian-Emperor Hotspot Volcano Group	HVO reported that two lava lakes at Kilauea were active during 20-26 July. The level of the summit lava lake fluctuated deep in the 150-m-diameter vent inset within the E wall of Halema'uma'u Crater and circulated with various patterns. Spattering occurred at locations along the edge of the lake. Periodic measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and occasionally fresh spatter nearby. At Pu'u 'O'o, lava from vents near the NE edge of the perched lava lake in the center of the crater floor continued to fill the circulating lake. The perched lake and crater floor continued to be uplifted and cracks on the doming crater floor were observed. Minor lava activity was noted in the Puka Nui and MLK pits, smaller craters to the W of the main Pu'u 'O'o crater. Based on several measurements throughout July, the crater floor was uplifted about 0.5-1 m per day. Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Kizimen (Russia) | 20 July-26 July 2011 | Continuing ActivityCite this Report
Kizimen Eastern Kamchatka Volcanic Arc	KVERT reported that during 15-22 July seismicity from Kizimen was above background levels and weak volcanic tremor continued to be detected. Satellite images showed a bright thermal anomaly on the volcano all week. Seismic data indicated that possible ash plumes rose to an altitude of 3.5 km (11,500 ft) a.s.l. during 19-20 July. A gas-and-steam plume detected in satellite imagery on 19 July drifted NW. Seismologists in the area on 20 July observed gas-and-ash plumes that rose to an altitude of 3 km (9,800 ft) a.s.l. and drifted 15 km E. The Aviation Color Code remained at Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Puyehue-Cordon Caulle (Chile) | 20 July-26 July 2011 | Continuing ActivityCite this Report
Puyehue-Cordon Caulle Andean Southern Volcanic Arc	OVDAS-SERNAGEOMIN reported that on 20 July cameras installed around the Puyehue-Cordón Caulle volcanic complex recorded gray ash plumes that rose 3 km above the Cordón Caulle rift zone. Satellite imagery showed that the plume drifted 80 km E, becoming diffuse. Incandescence up to 500 m above the crater was observed at night. During 20-21 July seismic signals indicated active lava flows. Cloudy weather on 21 July prevented crater observations. Eruption plumes observed in satellite imagery on 22 July drifted 250 km E and SE. Seismic data indicated that the lava flows had stopped. The next day plumes rose 1-2 km above the crater; satellite imagery detected plumes that drifted 100 km E and SE. On 25 July gray ash plumes rose as high as 2.5 km and drifted SE. Lava flows were again active based on seismic data. The Alert Level remained at Red. Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
Sheveluch (Russia) | 20 July-26 July 2011 | Continuing ActivityCite this Report
Sheveluch Eastern Kamchatka Volcanic Arc	KVERT reported that seismic activity at Shiveluch was moderate during 15-22 July and indicated that possible ash plumes rose to an altitude of 4 km (13,100 ft) a.s.l. during 14-15 and 20 July. Satellite imagery showed a thermal anomaly on the lava dome during 14-15 and 18-19 July. Ash plumes drifted 13 km SW on 15 July. The Aviation Color Code remained at Orange. Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

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)