Smithsonian / USGS Weekly Volcanic Activity Report

The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday and averaging 16 reported volcanoes, this is not a comprehensive list of all eruptions this week, but rather a summary of activity that meet criteria discussed in the "Criteria and Disclaimers" section below.

Volcanic activity reported here is preliminary and subject to change. Carefully reviewed, detailed narratives over longer time periods are published as reports of the Bulletin of the Global Volcanism Network available through volcano profile pages.

Smithsonian / USGS Weekly Volcanic Activity Report for the week of 23 July-29 July 2008
Name	Location	Eruption Start Date	Report Status
Anatahan	Mariana Islands (USA)	—	New
Chaiten	Southern Chile	—	New
Chikurachki	Paramushir Island (Russia)	—	New
Cleveland	Chuginadak Island (USA)	—	New
Dukono	Halmahera	1933 Aug 13	New
Karymsky	Eastern Kamchatka (Russia)	—	New
Llaima	Central Chile	—	New
Manam	Northeast of New Guinea	2014 Jun 29	New
Okmok	Fox Islands (USA)	—	New
Reventador	Ecuador	2008 Jul 27	New
Soufriere Hills	Montserrat	—	New
Aira	Kyushu (Japan)	2017 Mar 25	Continuing
Batu Tara	Komba Island	—	Continuing
Bezymianny	Central Kamchatka (Russia)	2016 Dec 5	Continuing
Kilauea	Hawaiian Islands (USA)	—	Continuing
Krakatau	Sunda Strait	—	Continuing
Rabaul	New Britain (Papua New Guinea)	—	Continuing
Santa Maria	Southwestern Guatemala	1922 Jun 22	Continuing
Semeru	Eastern Java	2017 Jun 6	Continuing
Sheveluch	Central Kamchatka (Russia)	1999 Aug 15	Continuing
Suwanosejima	Ryukyu Islands (Japan)	2004 Oct 23	Continuing
Tungurahua	Ecuador	—	Continuing
Ubinas	Peru	—	Continuing

All times are local unless otherwise stated.

Anatahan | 23 July-29 July 2008 | New Activity / Unrest Cite this Report

Anatahan
Mariana Islands (USA)

The USGS reported that seismic tremor from Anatahan slowly increased during 16-26 July. A diffuse sulfur-dioxide plume drifted W on 17 July. According to a Washington VAAC report a low-level plume possibly containing ash drifted 50 km NW on 26 July. The Volcanic Alert Level was raised to Advisory and the Aviation Color Code was raised to Yellow. According to another Washington VAAC report on 28 July, an ash plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted N. Seismic tremor continued to increase. A sulfur dioxide plume drifted NW. The Volcanic Alert Level was raised to Watch and the Aviation Color Code was raised to Orange. During 29-30 July, seismic tremor levels remained elevated, but possibly slightly decreased.

Source: Emergency Management Office of the Commonwealth of the Mariana Islands and United States Geological Survey Volcano Hazards Program

Chaiten | 23 July-29 July 2008 | New Activity / Unrest Cite this Report

Chaiten
Southern Chile

SERNAGEOMIN reported that clouds obscured camera views of Chaitén's eruption plume on 21 and 22 July. The E-drifting eruption plume was weaker when observed on 23 July and only rose to an altitude of less than 2 km (6,600 ft) a.s.l. In contrast, during 21-23 July earthquakes greater than M 2.6 increased in number and magnitude. The Alert Level was raised to Volcanic Alert Red Level 6.

An overflight on 24 July revealed a plume that rose to an altitude of 2 km (6,600 ft) a.s.l. It vented from an area S of a previous emission point, on the S flank of the new lava dome. The plume intermingled with other plumes generated by explosions. A gas-and-steam plume was emitted from a depression, also on the S flank, that was possibly formed by an explosion or partial collapse the previous day or two. Gas-and-steam plumes were emitted from the base of the E flank. On 24 July, ashfall near the city of Chaitén was about 3 cm thick. During 24-29 July, clouds generally prevented visual observations; occasionally the plume was visible and rose to an altitude of 2 km (6,600 ft) a.s.l. On 27 July, ashfall was again reported in the city of Chaitén.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)

Chikurachki | 23 July-29 July 2008 | New Activity / Unrest Cite this Report

Chikurachki
Paramushir Island (Russia)

Based on observations of satellite imagery, KVERT reported that on 29 July an ash plume from Chikurachki drifted more than 30 km WSW. The level of seismicity was unknown because Chikurachki lacks dedicated seismic instruments. The Level of Concern Color Code was raised to Yellow.

Based on reports from KVERT, the Tokyo VAAC reported that on 29 July, an eruption plume rose to an altitude of 6.1 km (20,000 ft) a.s.l.

Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Kamchatkan Volcanic Eruption Response Team (KVERT)

Cleveland | 23 July-29 July 2008 | New Activity / Unrest Cite this Report

Cleveland
Chuginadak Island (USA)

AVO reported that satellite views of Cleveland were hindered on 23 July due to cloud cover. On 24 July, a low-level ash plume and a strong thermal anomaly were noted near the summit. The thermal anomaly suggested the presence of an active lava flow. The thermal anomaly continued to be detected during 26-28 July and possible ash plumes drifted SE, E, and NE at altitudes of 3-6.1 km (10,000-20,000 ft) a.s.l. during 27-29 July.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Dukono | 23 July-29 July 2008 | New Activity / Unrest Cite this Report

Dukono
Halmahera

Based on observations of satellite imagery, the Darwin VAAC reported that during 25-27 July ash plumes from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Karymsky | 23 July-29 July 2008 | New Activity / Unrest Cite this Report

Karymsky
Eastern Kamchatka (Russia)

KVERT reported that seismic activity at Karymsky was above background levels on 18, 19, and 23 July and at background levels during 20-22 and 24-25. Explosive activity that produced ashfall was seen by area volcanologists. Interpretation of the seismic data suggested that on 19, 21, and 23 July possible ash-and-gas plumes rose to altitudes of 3 km (10,000 ft) a.s.l. Observations of satellite imagery revealed a thermal anomaly in the crater during 19-21 July. The Level of Concern Color Code was raised to Orange.

Based on information from the Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 25 July an ash plume rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted NE.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)

Llaima | 23 July-29 July 2008 | New Activity / Unrest Cite this Report

Llaima
Central Chile

SERNAGEOMIN reported that cloud cover prevented observations of Llaima during 22-23 July. On 24 July a bluish gas was emitted from a pyroclastic cone in the main crater and steam plumes rose from the W margin of the crater. Later that day, gas-and-ash plumes rose 100 m above the crater and dissipated to the SSE. During an overflight prompted by increased seismicity on 26 July, scientists observed weak explosions and airborne spatter from a double crater at the N base of the pyroclastic cone. Area residents reported hearing "detonations" coming from the direction of the volcano and they observed small ash plumes. Strombolian activity intensified and ejected material 500-800 m above the crater. Rhythmic explosions ejected spatter 1 km above the summit and up to 2 km towards the E. A plume rose to an altitude of 10 km (32,800 ft) a.s.l. Lava flows emitted at a high rate descended the W and S flanks and ice evaporated, producing steam plumes. SERNAGEOMIN raised the Alert Level to Red.

SERNAGEOMIN reported that the eruption during 26-27 July lasted for 11.5 hours. During 28 and 29 July, the volcano was in a state of calm.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)

Manam | 23 July-29 July 2008 | New Activity / Unrest Cite this Report

Manam
Northeast of New Guinea

Based on observations of satellite imagery and information from RVO, the Darwin VAAC reported that on 29 July low-level plumes from Manam rose to an altitude 2.4 km (8,000 ft) a.s.l. and drifted WNW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Okmok | 23 July-29 July 2008 | New Activity / Unrest Cite this Report

Okmok
Fox Islands (USA)

AVO reported that on 23 July, seismicity from Okmok changed from episodic volcanic tremor to nearly continuous mid-level volcanic tremor. Although cloud cover obscured views of Okmok, previously emitted ash plumes were observed to the ESE. On 24 July, a thermal anomaly was possibly present on satellite imagery. On 25 July, seismic amplitude increased. Based on pilot reports and observations of satellite imagery, AVO reported that ash plumes rose to altitudes of 10.7-12.2 km (35,000-40,000 ft) a.s.l. The Volcano Alert Level was raised to Warning and the Aviation Color Code was raised to Red.

On 26 July, seismic activity decreased and satellite imagery indicated that ash plumes rose to altitudes of 6.1-6.7 km (20,000-22,000 ft) a.s.l. The Volcano Alert Level was lowered to Watch and the Aviation Color Code was lowered to Orange. Seismicity increased again on 27 July. Satellite imagery possibly indicated another thermal anomaly; a possible plume at an altitude of less than 3 km (10,000 ft) a.s.l. was also noted. On 28 July, seismic tremor decreased. An ash plume at a possible altitude of 8.2 km (27,000 ft) a.s.l. drifted 90 km SE. Seismicity changed from nearly continuous volcanic tremor to episodic. Later that day and on 29 July, ash plumes possibly rose to an altitude of 10.7 km (35,000 ft) a.s.l. and drifted E to SE. The Volcano Alert Level was raised to Warning and the Aviation Color Code was raised to Red.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Reventador | 23 July-29 July 2008 | New Activity / Unrest Cite this Report

Reventador
Ecuador

The IG reported that the number of earthquakes per day from Reventador increased during July and were the greatest on 24 and 25 July. At 1500 on 27 July, continuous seismic tremor was registered and was followed by observations of incandescence around the crater. Thermal anomalies were also identified on satellite imagery. At 1900 explosions produced ash plumes and ejected incandescent material that fell onto and rolled down the flanks. On 28 July, ash plumes drifted NW and W. Ashfall was reported in Olmedo, about 50 km NW. Later that day, ash plumes rose to altitudes of 4-6 km (13,100-19,700 ft) a.s.l. and drifted NW. On 29 July, steam plumes rose from the crater and drifted NW. A sulfur smell was reported at areas around the volcano. A lava flow traveled S.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

Soufriere Hills | 23 July-29 July 2008 | New Activity / Unrest Cite this Report

Soufriere Hills
Montserrat

MVO reported no evidence of lava-dome growth at Soufrière Hills during 18-26 July. At least six eruptive events occurred during 20-22 July, each producing ash plumes that rose to altitudes of 2 km (6,000 ft) a.s.l. or lower. The ash plumes drifted W; ashfall was reported in Old Towne. Rumbling noises were heard in nearby areas and lightning strikes were observed. Small pyroclastic flows during 20-21 July traveled E down the Tar River valley with the largest one reaching within 500 m of the ocean. The Alert Level remained elevated at 4 (on a scale of 0-5).

On 26 July, seismicity increased significantly and then decreased. Seismicity increased again at approximately 0100 on 27 July and continued at a high level until about 0935 when a short series of eruptive events started. The first and largest ash-venting event of this series produced an ash plume that rose to an altitude of 2.5 km (8,000 ft) a.s.l. and drifted W and NW. Ashfall was reported in Plymouth and St George's Hill. Two events that followed produced ash plumes to an altitude of 1.5 km (5,000 ft) a.s.l.

A partial lava-dome collapse began at 1127 on 28 July without any precursory activity. Part of the dome's W flank collapsed and generated pyroclastic flows that reached Plymouth and the sea. A few explosions during the collapse produced ash plumes; the largest ash plume rose to an altitude of 12 km (40,000 ft) a.s.l.

Source: Montserrat Volcano Observatory (MVO)

Aira | 23 July-29 July 2008 | Continuing ActivityCite this Report

Aira
Kyushu (Japan)

Based on information from JMA, the Tokyo VAAC reported that during 25-28 July ash plumes from Sakura-jima rose to altitudes of 2.4-4.3 km (8,000-14,000 ft) a.s.l. and drifted N, NE, and S.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Batu Tara | 23 July-29 July 2008 | Continuing ActivityCite this Report

Batu Tara
Komba Island

Based on observations of satellite imagery, the Darwin VAAC reported that during 24-29 July ash plumes from Batu Tara rose to an altitude of 1.5-3.7 km (5,000-12,000 ft) a.s.l. and drifted WSW, W, NW, and N.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Bezymianny | 23 July-29 July 2008 | Continuing ActivityCite this Report

Bezymianny
Central Kamchatka (Russia)

KVERT reported that seismic activity at Bezymianny was above background levels on 20 July and at background levels the other days during 18-25 July. Fumarolic activity was observed during 18-22 July and area volcanologists reported that the lava dome continued to grow. Weak thermal anomalies over the lava dome were detected in satellite imagery on 18, 19, and 20 July. KVERT lowered the level of Concern Color Code to Yellow.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Kilauea | 23 July-29 July 2008 | Continuing ActivityCite this Report

Kilauea
Hawaiian Islands (USA)

Based on visual observations from HVO geologists, video footage, and web camera views, HVO reported that during 23-29 July, lava flowed SE through a lava tube system from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex to the Waikupanaha ocean entry. A bench collapse at the ocean entry occurred on 22 July. Pu'u 'O'o crater incandescence originated from vents on the crater floor and was reflected in a gas plume emitted from a vent on the E wall. A surface lava flow was seen behind the coastal bench on 28 July. The sulfur dioxide emission rate at Pu'u 'O'o was high at 4,700 and 5,400 tonnes per day on 24 and 26 July, respectively; the average background rate is about 2,000 tonnes per day.

During the reporting period, Kilauea earthquakes were variously located beneath Halema'uma'u crater, along the Koa'e fault system, beneath Makaopuhi crater, along the S-flank faults, and along the SW rift zone. Beneath Halema'uma'u crater, another 20-60 small earthquakes per day also occurred but were too small to be located more precisely. The vent in the crater continued to produce a white plume with minor ash content that drifted mainly SW. Night-time incandescence was seen at the base of the plume. Rock-clattering sounds were heard in the vicinity of Halema'uma'u crater. The sulfur dioxide emission rate was high and between 600 and 800 tonnes per day, during 24-26 July. The pre-2008 background rate was 150-200 tonnes per day. On 26 July, incandescent material was ejected from the vent in Halema'uma'u crater.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Krakatau | 23 July-29 July 2008 | Continuing ActivityCite this Report

Krakatau
Sunda Strait

Based on observations of satellite imagery, the Darwin VAAC reported that ash plumes from Anak Krakatau rose to an altitude of 3 km (10,000 ft) a.s.l. on 27 July and drifted NW. A meteorological cloud obscured satellite views the next day but the VAAC warned that ash may still be present in the area.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Rabaul | 23 July-29 July 2008 | Continuing ActivityCite this Report

Rabaul
New Britain (Papua New Guinea)

Based on observations of satellite imagery and information from RVO, the Darwin VAAC reported that during 23-24 and 26-29 July ash plumes from Rabaul caldera's Tavurvur cone rose to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted W and NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Santa Maria | 23 July-29 July 2008 | Continuing ActivityCite this Report

Santa Maria
Southwestern Guatemala

INSIVUMEH reported that on 22 July seismic stations monitoring Santa María's Santiaguito lava dome complex detected a lahar below the S flank in the Nima I river. Explosions observed on 23, 28, and 29 July from Caliente cone produced ash plumes that rose to altitudes of 2.8-3.3 km (9,200-10,800 ft) a.s.l. and drifted SW and W. Ashfall was reported in areas downwind. A lava flow and avalanches of blocks descended the SW flank. On 28 July, weak pyroclastic flows also traveled down the SW flank.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Semeru | 23 July-29 July 2008 | Continuing ActivityCite this Report

Semeru
Eastern Java

The Darwin VAAC reported that on 27 July an ash plume at an altitude of 4.3 km (14,000 ft) a.s.l. was spotted by a pilot in the vicinity of Semeru. Ash was not identified on satellite imagery.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Sheveluch | 23 July-29 July 2008 | Continuing ActivityCite this Report

Sheveluch
Central Kamchatka (Russia)

KVERT reported that seismic activity at Shiveluch was slightly above background levels during 18-25 July. Moderate fumarolic activity was seen on 18 and 22 July. Observations of satellite imagery revealed a thermal anomaly on the lava dome during 18-22 July; clouds obscured views on other days. The Level of Concern Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Suwanosejima | 23 July-29 July 2008 | Continuing ActivityCite this Report

Suwanosejima
Ryukyu Islands (Japan)

Based on pilot reports, the Tokyo VAAC reported that on 30 July an ash plume from Suwanose-jima rose to an altitude of 0.6 km (2,000 ft) a.s.l. and drifted S.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Tungurahua | 23 July-29 July 2008 | Continuing ActivityCite this Report

Tungurahua
Ecuador

The IG reported that during 22-23 July, explosions from Tungurahua were detected by the seismic network. An ash plume rose to an altitude of 9 km (29,500 ft) a.s.l. On 25 July, lahars descended two drainages on the W flank. On 26 July, ash-and-steam plumes drifted NW and SW, and explosions and roaring noises were reported. Nighttime incandescence from the crater was noted. On 27 July, roaring noises accompanied ash plumes that rose to altitudes of 8-10 km (26,200-32,800 ft) a.s.l. Ashfall was reported in areas to the SW. During 27-29 July, incandescence was seen around the crater and blocks rolled 800 m down the flanks. Noises were reported and explosions caused windows to vibrate. Ashfall was reported in areas to the SW.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

Ubinas | 23 July-29 July 2008 | Continuing ActivityCite this Report

Ubinas
Peru

Based on SIGMET reports, the Buenos Aires VAAC reported that ash plumes from Ubinas rose to altitudes of 5.5-5.8 km (18,000-19,000 ft) a.s.l. on 23 July and drifted SE.

Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)

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Criteria & Disclaimers

Criteria

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.

Disclaimers

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.

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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)

Report for Anatahan
The USGS reported that seismic tremor from Anatahan slowly increased during 16-26 July. A diffuse sulfur-dioxide plume drifted W on 17 July. According to a Washington VAAC report a low-level plume possibly containing ash drifted 50 km NW on 26 July. The Volcanic Alert Level was raised to Advisory and the Aviation Color Code was raised to Yellow. According to another Washington VAAC report on 28 July, an ash plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted N. Seismic tremor continued to increase. A sulfur dioxide plume drifted NW. The Volcanic Alert Level was raised to Watch and the Aviation Color Code was raised to Orange. During 29-30 July, seismic tremor levels remained elevated, but possibly slightly decreased.
Source: Emergency Management Office of the Commonwealth of the Mariana Islands and United States Geological Survey Volcano Hazards Program

Report for Chaiten
SERNAGEOMIN reported that clouds obscured camera views of Chaitén's eruption plume on 21 and 22 July. The E-drifting eruption plume was weaker when observed on 23 July and only rose to an altitude of less than 2 km (6,600 ft) a.s.l. In contrast, during 21-23 July earthquakes greater than M 2.6 increased in number and magnitude. The Alert Level was raised to Volcanic Alert Red Level 6.

An overflight on 24 July revealed a plume that rose to an altitude of 2 km (6,600 ft) a.s.l. It vented from an area S of a previous emission point, on the S flank of the new lava dome. The plume intermingled with other plumes generated by explosions. A gas-and-steam plume was emitted from a depression, also on the S flank, that was possibly formed by an explosion or partial collapse the previous day or two. Gas-and-steam plumes were emitted from the base of the E flank. On 24 July, ashfall near the city of Chaitén was about 3 cm thick. During 24-29 July, clouds generally prevented visual observations; occasionally the plume was visible and rose to an altitude of 2 km (6,600 ft) a.s.l. On 27 July, ashfall was again reported in the city of Chaitén.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)

Report for Chikurachki
Based on observations of satellite imagery, KVERT reported that on 29 July an ash plume from Chikurachki drifted more than 30 km WSW. The level of seismicity was unknown because Chikurachki lacks dedicated seismic instruments. The Level of Concern Color Code was raised to Yellow.

Based on reports from KVERT, the Tokyo VAAC reported that on 29 July, an eruption plume rose to an altitude of 6.1 km (20,000 ft) a.s.l.
Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Kamchatkan Volcanic Eruption Response Team (KVERT)

Report for Cleveland
AVO reported that satellite views of Cleveland were hindered on 23 July due to cloud cover. On 24 July, a low-level ash plume and a strong thermal anomaly were noted near the summit. The thermal anomaly suggested the presence of an active lava flow. The thermal anomaly continued to be detected during 26-28 July and possible ash plumes drifted SE, E, and NE at altitudes of 3-6.1 km (10,000-20,000 ft) a.s.l. during 27-29 July.
Source: US Geological Survey Alaska Volcano Observatory (AVO)

Report for Dukono
Based on observations of satellite imagery, the Darwin VAAC reported that during 25-27 July ash plumes from Dukono rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted W.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Karymsky
KVERT reported that seismic activity at Karymsky was above background levels on 18, 19, and 23 July and at background levels during 20-22 and 24-25. Explosive activity that produced ashfall was seen by area volcanologists. Interpretation of the seismic data suggested that on 19, 21, and 23 July possible ash-and-gas plumes rose to altitudes of 3 km (10,000 ft) a.s.l. Observations of satellite imagery revealed a thermal anomaly in the crater during 19-21 July. The Level of Concern Color Code was raised to Orange.

Based on information from the Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 25 July an ash plume rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted NE.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)

Report for Llaima
SERNAGEOMIN reported that cloud cover prevented observations of Llaima during 22-23 July. On 24 July a bluish gas was emitted from a pyroclastic cone in the main crater and steam plumes rose from the W margin of the crater. Later that day, gas-and-ash plumes rose 100 m above the crater and dissipated to the SSE. During an overflight prompted by increased seismicity on 26 July, scientists observed weak explosions and airborne spatter from a double crater at the N base of the pyroclastic cone. Area residents reported hearing "detonations" coming from the direction of the volcano and they observed small ash plumes. Strombolian activity intensified and ejected material 500-800 m above the crater. Rhythmic explosions ejected spatter 1 km above the summit and up to 2 km towards the E. A plume rose to an altitude of 10 km (32,800 ft) a.s.l. Lava flows emitted at a high rate descended the W and S flanks and ice evaporated, producing steam plumes. SERNAGEOMIN raised the Alert Level to Red.

SERNAGEOMIN reported that the eruption during 26-27 July lasted for 11.5 hours. During 28 and 29 July, the volcano was in a state of calm.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)

Report for Manam
Based on observations of satellite imagery and information from RVO, the Darwin VAAC reported that on 29 July low-level plumes from Manam rose to an altitude 2.4 km (8,000 ft) a.s.l. and drifted WNW.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Okmok
AVO reported that on 23 July, seismicity from Okmok changed from episodic volcanic tremor to nearly continuous mid-level volcanic tremor. Although cloud cover obscured views of Okmok, previously emitted ash plumes were observed to the ESE. On 24 July, a thermal anomaly was possibly present on satellite imagery. On 25 July, seismic amplitude increased. Based on pilot reports and observations of satellite imagery, AVO reported that ash plumes rose to altitudes of 10.7-12.2 km (35,000-40,000 ft) a.s.l. The Volcano Alert Level was raised to Warning and the Aviation Color Code was raised to Red.

On 26 July, seismic activity decreased and satellite imagery indicated that ash plumes rose to altitudes of 6.1-6.7 km (20,000-22,000 ft) a.s.l. The Volcano Alert Level was lowered to Watch and the Aviation Color Code was lowered to Orange. Seismicity increased again on 27 July. Satellite imagery possibly indicated another thermal anomaly; a possible plume at an altitude of less than 3 km (10,000 ft) a.s.l. was also noted. On 28 July, seismic tremor decreased. An ash plume at a possible altitude of 8.2 km (27,000 ft) a.s.l. drifted 90 km SE. Seismicity changed from nearly continuous volcanic tremor to episodic. Later that day and on 29 July, ash plumes possibly rose to an altitude of 10.7 km (35,000 ft) a.s.l. and drifted E to SE. The Volcano Alert Level was raised to Warning and the Aviation Color Code was raised to Red.
Source: US Geological Survey Alaska Volcano Observatory (AVO)

Report for Reventador
The IG reported that the number of earthquakes per day from Reventador increased during July and were the greatest on 24 and 25 July. At 1500 on 27 July, continuous seismic tremor was registered and was followed by observations of incandescence around the crater. Thermal anomalies were also identified on satellite imagery. At 1900 explosions produced ash plumes and ejected incandescent material that fell onto and rolled down the flanks. On 28 July, ash plumes drifted NW and W. Ashfall was reported in Olmedo, about 50 km NW. Later that day, ash plumes rose to altitudes of 4-6 km (13,100-19,700 ft) a.s.l. and drifted NW. On 29 July, steam plumes rose from the crater and drifted NW. A sulfur smell was reported at areas around the volcano. A lava flow traveled S.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

Report for Soufriere Hills
MVO reported no evidence of lava-dome growth at Soufrière Hills during 18-26 July. At least six eruptive events occurred during 20-22 July, each producing ash plumes that rose to altitudes of 2 km (6,000 ft) a.s.l. or lower. The ash plumes drifted W; ashfall was reported in Old Towne. Rumbling noises were heard in nearby areas and lightning strikes were observed. Small pyroclastic flows during 20-21 July traveled E down the Tar River valley with the largest one reaching within 500 m of the ocean. The Alert Level remained elevated at 4 (on a scale of 0-5).

On 26 July, seismicity increased significantly and then decreased. Seismicity increased again at approximately 0100 on 27 July and continued at a high level until about 0935 when a short series of eruptive events started. The first and largest ash-venting event of this series produced an ash plume that rose to an altitude of 2.5 km (8,000 ft) a.s.l. and drifted W and NW. Ashfall was reported in Plymouth and St George's Hill. Two events that followed produced ash plumes to an altitude of 1.5 km (5,000 ft) a.s.l.

A partial lava-dome collapse began at 1127 on 28 July without any precursory activity. Part of the dome's W flank collapsed and generated pyroclastic flows that reached Plymouth and the sea. A few explosions during the collapse produced ash plumes; the largest ash plume rose to an altitude of 12 km (40,000 ft) a.s.l.
Source: Montserrat Volcano Observatory (MVO)

Report for Aira
Based on information from JMA, the Tokyo VAAC reported that during 25-28 July ash plumes from Sakura-jima rose to altitudes of 2.4-4.3 km (8,000-14,000 ft) a.s.l. and drifted N, NE, and S.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Report for Batu Tara
Based on observations of satellite imagery, the Darwin VAAC reported that during 24-29 July ash plumes from Batu Tara rose to an altitude of 1.5-3.7 km (5,000-12,000 ft) a.s.l. and drifted WSW, W, NW, and N.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Bezymianny
KVERT reported that seismic activity at Bezymianny was above background levels on 20 July and at background levels the other days during 18-25 July. Fumarolic activity was observed during 18-22 July and area volcanologists reported that the lava dome continued to grow. Weak thermal anomalies over the lava dome were detected in satellite imagery on 18, 19, and 20 July. KVERT lowered the level of Concern Color Code to Yellow.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Report for Kilauea
Based on visual observations from HVO geologists, video footage, and web camera views, HVO reported that during 23-29 July, lava flowed SE through a lava tube system from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex to the Waikupanaha ocean entry. A bench collapse at the ocean entry occurred on 22 July. Pu'u 'O'o crater incandescence originated from vents on the crater floor and was reflected in a gas plume emitted from a vent on the E wall. A surface lava flow was seen behind the coastal bench on 28 July. The sulfur dioxide emission rate at Pu'u 'O'o was high at 4,700 and 5,400 tonnes per day on 24 and 26 July, respectively; the average background rate is about 2,000 tonnes per day.

During the reporting period, Kilauea earthquakes were variously located beneath Halema'uma'u crater, along the Koa'e fault system, beneath Makaopuhi crater, along the S-flank faults, and along the SW rift zone. Beneath Halema'uma'u crater, another 20-60 small earthquakes per day also occurred but were too small to be located more precisely. The vent in the crater continued to produce a white plume with minor ash content that drifted mainly SW. Night-time incandescence was seen at the base of the plume. Rock-clattering sounds were heard in the vicinity of Halema'uma'u crater. The sulfur dioxide emission rate was high and between 600 and 800 tonnes per day, during 24-26 July. The pre-2008 background rate was 150-200 tonnes per day. On 26 July, incandescent material was ejected from the vent in Halema'uma'u crater.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Report for Krakatau
Based on observations of satellite imagery, the Darwin VAAC reported that ash plumes from Anak Krakatau rose to an altitude of 3 km (10,000 ft) a.s.l. on 27 July and drifted NW. A meteorological cloud obscured satellite views the next day but the VAAC warned that ash may still be present in the area.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Rabaul
Based on observations of satellite imagery and information from RVO, the Darwin VAAC reported that during 23-24 and 26-29 July ash plumes from Rabaul caldera's Tavurvur cone rose to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted W and NW.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Santa Maria
INSIVUMEH reported that on 22 July seismic stations monitoring Santa María's Santiaguito lava dome complex detected a lahar below the S flank in the Nima I river. Explosions observed on 23, 28, and 29 July from Caliente cone produced ash plumes that rose to altitudes of 2.8-3.3 km (9,200-10,800 ft) a.s.l. and drifted SW and W. Ashfall was reported in areas downwind. A lava flow and avalanches of blocks descended the SW flank. On 28 July, weak pyroclastic flows also traveled down the SW flank.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Report for Semeru
The Darwin VAAC reported that on 27 July an ash plume at an altitude of 4.3 km (14,000 ft) a.s.l. was spotted by a pilot in the vicinity of Semeru. Ash was not identified on satellite imagery.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Sheveluch
KVERT reported that seismic activity at Shiveluch was slightly above background levels during 18-25 July. Moderate fumarolic activity was seen on 18 and 22 July. Observations of satellite imagery revealed a thermal anomaly on the lava dome during 18-22 July; clouds obscured views on other days. The Level of Concern Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Report for Suwanosejima
Based on pilot reports, the Tokyo VAAC reported that on 30 July an ash plume from Suwanose-jima rose to an altitude of 0.6 km (2,000 ft) a.s.l. and drifted S.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Report for Tungurahua
The IG reported that during 22-23 July, explosions from Tungurahua were detected by the seismic network. An ash plume rose to an altitude of 9 km (29,500 ft) a.s.l. On 25 July, lahars descended two drainages on the W flank. On 26 July, ash-and-steam plumes drifted NW and SW, and explosions and roaring noises were reported. Nighttime incandescence from the crater was noted. On 27 July, roaring noises accompanied ash plumes that rose to altitudes of 8-10 km (26,200-32,800 ft) a.s.l. Ashfall was reported in areas to the SW. During 27-29 July, incandescence was seen around the crater and blocks rolled 800 m down the flanks. Noises were reported and explosions caused windows to vibrate. Ashfall was reported in areas to the SW.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

Report for Ubinas
Based on SIGMET reports, the Buenos Aires VAAC reported that ash plumes from Ubinas rose to altitudes of 5.5-5.8 km (18,000-19,000 ft) a.s.l. on 23 July and drifted SE.
Source: Buenos Aires Volcanic Ash Advisory Center (VAAC)