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Smithsonian / USGS Weekly Volcanic Activity Report

Weekly Volcanic Activity Map

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 25 August-31 August 2021
Name Location Eruption Start Date Report Status
Atka Andreanof Islands (USA) New
Chirinkotan Kuril Islands (Russia) New
Fukutoku-Oka-no-Ba Volcano Islands (Japan) New
Kilauea Hawaiian Islands (USA) 2021 Sep 29 New
Krysuvik-Trolladyngja Iceland New
Pavlof United States 2021 Aug 5 New
Semisopochnoi Aleutian Islands (USA) 2021 Feb 2 ± 2 days New
Dukono Halmahera (Indonesia) 1933 Aug 13 Continuing
Ebeko Paramushir Island (Russia) 2016 Oct 20 Continuing
Etna Sicily (Italy) 2013 Sep 3 Continuing
Great Sitkin Andreanof Islands (USA) 2021 May 25 Continuing
Kadovar Papua New Guinea 2018 Jan 5 Continuing
Karymsky Eastern Kamchatka (Russia) 2020 Apr 1 Continuing
Katmai United States Continuing
Lewotolok Lembata Island (Indonesia) 2020 Nov 27 Continuing
Merapi Central Java (Indonesia) 2020 Dec 31 Continuing
Nevado del Ruiz Colombia 2014 Nov 18 Continuing
Rincon de la Vieja Costa Rica 2021 Jun 28 Continuing
Sabancaya Peru 2016 Nov 6 Continuing
Semeru Eastern Java (Indonesia) 2014 Apr 1 ± 15 days Continuing
Sheveluch Central Kamchatka (Russia) 1999 Aug 15 Continuing
Sinabung Indonesia 2020 Aug 8 Continuing
Stromboli Aeolian Islands (Italy) 1934 Feb 2 Continuing
Suwanosejima Ryukyu Islands (Japan) 2004 Oct 23 Continuing
Yasur Vanuatu 1774 Jul 2 (in or before) ± 182 days Continuing
All times are local unless otherwise stated.
Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 17,094 individual reports over 1,084 weeks (average of 16 per week) on 316 different volcanoes.

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Agung Concepcion Ijen Little Sitkin Peuet Sague Spurr
Ahyi Copahue Iliamna Llaima Pinatubo St. Helens
Aira Cotopaxi Iliwerung Loihi Planchon-Peteroa Stromboli
Akan Cuicocha Inielika Lokon-Empung Poas Sulu Range
Alaid Cumbal Ioto Lopevi Popocatepetl Sumbing
Alu-Dalafilla Dabbahu Irazu Machin Puyehue-Cordon Caulle Sundoro
Ambae Dempo Iya Makian Rabaul Suretamatai
Ambang Descabezado Grande Izu-Torishima Makushin Raikoke Suwanosejima
Ambrym Dieng Volcanic Complex Jackson Segment Maly Semyachik Ranakah Taal
Anatahan Dukono Kaba Manam Raoul Island Tair, Jebel at
Aniakchak Ebeko Kadovar Manda Hararo Rasshua Takawangha
Antillanca Volcanic Complex Ebulobo Kambalny Marapi Raung Talang
Antuco Egon Kanaga Maroa Redoubt Tambora
Apoyeque Ekarma Kanlaon Martin Reventador Tanaga
Arenal Epi Karangetang Masaya Reykjanes Tandikat-Singgalang
Asamayama Erebus Karkar Maule, Laguna del Rincon de la Vieja Tangkoko-Duasudara
Askja Erta Ale Karthala Mauna Loa Rinjani Tangkuban Parahu
Asosan Etna Karymsky Mayon Ritter Island Tara, Batu
Atka Etorofu-Yakeyama [Grozny Group] Kasatochi McDonald Islands Rotorua Telica
Augustine Eyjafjallajokull Katla Melimoyu Ruang Tenerife
Avachinsky Fernandina Katmai Merapi Ruapehu Tengger Caldera
Awu Fogo Kavachi Midagahara Ruiz, Nevado del Three Sisters
Axial Seamount Fonualei Kelimutu Misti, El Sabancaya Tinakula
Azul, Cerro Fournaise, Piton de la Kelut Miyakejima Sakar Tofua
Azumayama Fourpeaked Kerinci Momotombo Salak Tokachidake
Bagana Fuego Ketoi Monowai San Cristobal Tolbachik
Balbi Fujisan Kharimkotan Montagu Island San Miguel Toliman
Bamus Fukutoku-Oka-no-Ba Kick 'em Jenny Moyorodake [Medvezhia] San Vicente Tongariro
Banda Api Galeras Kikai Mutnovsky Sangay Tungurahua
Bardarbunga Galunggung Kilauea Myojinsho Sangeang Api Turrialba
Barren Island Gamalama Kirishimayama Nabro Santa Ana Ubinas
Batur Gamkonora Kizimen Negra, Sierra Santa Maria Ugashik-Peulik
Bezymianny Gareloi Klyuchevskoy Negro, Cerro Sarigan Ukinrek Maars
Bogoslof Gaua Kolokol Group Nightingale Island Sarychev Peak Ulawun
Brava Gorely Korovin Nishinoshima Saunders Unnamed
Bristol Island Great Sitkin Koryaksky Nisyros Savo Unnamed
Bulusan Grimsvotn Krakatau Novarupta Semeru Veniaminof
Calbuco Guagua Pichincha Krummel-Garbuna-Welcker NW Rota-1 Semisopochnoi Villarrica
Callaqui Guallatiri Krysuvik-Trolladyngja Nyamulagira Seulawah Agam Vulcano
Cameroon Guntur Kuchinoerabujima Nyiragongo Sheveluch West Mata
Campi Flegrei del Mar di Sicilia Hachijojima Kurikomayama Okataina Shishaldin Westdahl
Cayambe Hakoneyama Kusatsu-Shiranesan Okmok Simbo Whakaari/White Island
Chachadake [Tiatia] Heard Kverkfjoll Ontakesan Sinabung Witori
Chaiten Hekla La Palma Oraefajokull Sinarka Wolf
Chiginagak Helgrindur Lamington Osorno Siple Yasur
Chikurachki Hierro Lamongan Pacaya Sirung Zaozan [Zaosan]
Chiles-Cerro Negro Hokkaido-Komagatake Langila Pagan Slamet Zavodovski
Chillan, Nevados de Home Reef Lanin Palena Volcanic Group Snaefellsjokull Zhupanovsky
Chirinkotan Hood Lascar Paluweh Soputan Zubair Group
Chirpoi Huaynaputina Lateiki Panarea Sorikmarapi
Ciremai Hudson, Cerro Lengai, Ol Doinyo Papandayan Sotara
Cleveland Huila, Nevado del Leroboleng Parker Soufriere Hills
Colima Hunga Tonga-Hunga Ha'apai Lewotobi Pavlof Soufriere St. Vincent
Colo Ibu Lewotolok Pelee South Sarigan Seamount
 News Feeds and Google Placemarks


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The RSS (Really Simple Syndication) feed is identical to the Weekly Volcanic Activity Report minus some features including the header information (latitude and longitude and summit elevation), the Geologic Summary, and a link to the volcano's page from the Global Volcanism Program. At the end of each report is a list of the sources used. Each volcano report includes a link from the volcano's name back to the more complete information in the Weekly Volcanic Activity Report on the Smithsonian website. This feature was first made available on 5 March 2008.



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A Google Earth network link for the Weekly Volcanic Activity Report can be loaded into the free Google Earth software, and in turn will load placemarks for volcanoes in the current weekly report. Placemark balloons include the volcano name, report date, report text, sources, and links back to the GVP volcano profile page and to the complete Weekly Report for that week. This feature was first made available on 1 April 2009.

 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.

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)

Report for Atka
AVO lowered the Aviation Color Code and Volcano Alert Level for the Atka Volcanic Complex to Green and Normal, respectively, on 27 August, noting that seismicity had returned to baseline levels over the previous week.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Chirinkotan
SVERT reported that during 23-26 August ash plumes from Chirinkotan were visible rising 2.5-3.5 km (8,200-11,500 ft) a.s.l. and drifting S and SW. KVERT maintained the Aviation Color Code at Orange (the second highest level on a four-color scale).
Sources: Sakhalin Volcanic Eruption Response Team (SVERT), Kamchatkan Volcanic Eruption Response Team (KVERT)
Report for Fukutoku-Oka-no-Ba
The Japan Coast Guard reported that during a 26 August overflight of Fukutoku-Oka-no-Ba, observers noted that the W island was unchanged while the E side had mostly eroded, leaving two small islands. While no eruptions were visible, gray material from the central vent was intermittently ejected to the sea surface and brown, discolored water was widely distributed, especially to the W.
Source: Japan Coast Guard
Report for Kilauea
HVO reported that a seismic swarm and ground deformation continued beneath the S part of Kilauea’s summit during 24-25 August. The rate of earthquakes per hour peaked at 28 during 1900-2000 on 24 August and then decreased to 5-12 through 25 August. Most of the earthquakes were between magnitudes 1 and 2, occurring at depths of 1-2 km. By 26 August seismicity and ground deformation levels had decreased, suggesting magma was no longer moving; HVO lowered the Volcano Alert Level and Aviation Color Code to Advisory and Yellow, respectively. Later that day, ground deformation began again in the S part of the caldera at around 1800 and was followed by an increase in seismicity after 2030. Earthquakes in the swarm were located at depths of 1-3 km. The strongest earthquake was a M 2.8, though the majority were less than M 1. The rate of events per hour was 16, with a peak of 24 just after midnight on 27 August, and then declined to about six. Seismicity remained low through 30 August with 7-8 events per hour, all under M 2 and at depths of 1-4 km. Deformation continued to be detected at variable rates. Although the deformation and seismicity suggested renewed magma movement, the data did not indicate an upward movement of magma.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Report for Krysuvik-Trolladyngja
The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 25-31 August, though weather often obscured the view of the vents. Low lava fountaining and overflows from the main vent were interspersed with periods of calm. Parts of the crater sometimes collapsed and produced minor ash clouds based on webcam views. According to a news article, lava flowed into the S part of Meradalir valley and then down a hillside into Nàtthagi valley on 26 August in multiple branches. Observers noted that parts of the flows were turbulent and splashed above the flow surface. Lava stopped advancing at around 1600 as the eruption paused. A geophysicist noted that lava had been flowing S more often due to the new vent that had opened on the flank of the cone during the previous few weeks. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities also warned of gas emission hazards.
Sources: Icelandic Meteorological Office (IMO), Icelandic National Broadcasting Service (RUV), Icelandic National Broadcasting Service (RUV)
Report for Pavlof
AVO reported that several small daily explosions at Pavlof were recorded by seismic and infrasound sensors during 24-26 August. A pilot observed an ash plume from an explosion that rose to 3.7 km (12,000 ft) a.s.l on 25 August. Seismicity was relatively quiet during 27-31 August; elevated surface temperatures continued to be recorded on most of those days. One explosion on 28 August produced an ash emission visible in webcam data. The Volcano Alert Level and Aviation Color Code remained at Watch and Orange, respectively.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Semisopochnoi
AVO reported that eruptive activity at Semisopochnoi's North Cerberus crater continued during 25-31 August. Multiple daily explosions were detected by seismic and infrasound networks. Ash-and-steam plumes from the explosions were sometimes confirmed in webcam images, in satellite data, and by nearby observers; plumes rose no higher than 3 km (10,000 ft) a.s.l. and produced local ashfall on the island. Daily sulfur dioxide emissions were identified in satellite images, drifting as far as 300 km NW during 29-31 August. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Dukono
The Darwin VAAC reported that during 24 and 26-27 August white-and-gray ash plumes from Dukono rose 2.3 km (7,000 ft) a.s.l. and drifted W, SW, and S. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.
Sources: Darwin Volcanic Ash Advisory Centre (VAAC), Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Ebeko
According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, explosions during 20-21 and 24-25 August produced ash plumes that rose as high as 4.6 km (15,100 ft) a.s.l. and drifted SE. A thermal anomaly was identified in satellite images during 20 and 23-25 August. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Report for Etna
INGV reported that activity at Etna was concentrated at the Southeast Crater (SEC) during 23-29 August. Gas emissions rose from Bocca Nuova crater. A series of explosions at SEC that began at 1530 on 27 August and continued through the next morning produced ash puffs. Strombolian activity began in the early afternoon of 29 August and within an hour, lava fountains were visible rising up to 400 m above the vent. Ash emissions rose a few hundred meters. The activity varied in intensity and during intense periods, ash plumes rose up to 10 km above the summit. Ash and lapilli fell in areas to the E, including in Fornazzo, Milo, San Alfio, and Giarre. Lava flows from the SEC traveled SW and one from the E base traveled E toward the Valle del Bove.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Great Sitkin
AVO reported that the lava dome at Great Sitkin continued to grow, reaching 880 m in diameter by 25 August and 1,090 m during 28-29 August. Elevated surface temperatures and small earthquakes were detected during 25-31 August, consistent with the growing dome. Daily steam-and-gas plumes were observed in satellite data and by local observers. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Kadovar
Based on satellite and wind model data, the Darwin VAAC reported that on 27 and 30 August ash plumes from Kadovar rose to altitudes of 1.2-1.5 km (4,000-5,000 ft) a.s.l. and drifted W and WNW.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Report for Karymsky
KVERT reported that during 20-27 August daily gas-and-ash plumes from Karymsky were identified in satellite images drifting 94 km NE, E, and SE. Daily thermal anomalies were also visible. The Tokyo VAAC noted that during 25-27 August ash plumes rose to 3-4.6 (10,000-14,000 ft) a.s.l. and drifted E and NE, based on information from Petropavlovsk-Kamchatsky Airport (UHPP) and satellite data. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Report for Katmai
AVO reported that on 28 August strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes picked up unconsolidated ash and drifted SE towards Kodiak Island at an altitude up to 1.8 km (6,000 ft) a.s.l. The ash was originally deposited during the Novarupta eruption in 1912. The Volcano Alert Level remained at Normal and the Aviation Color Code remained at Green.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Lewotolok
PVMBG reported that the eruption at Lewotolok continued during 25-30 August. White, gray, and sometimes black plumes rose as high as 1.2 km above the summit and drifted W and NW. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit crater.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Merapi
BPPTKG reported that of Merapi’s two lava domes, the dome just below the SW rim was more active than the dome in the summit crater during 20-26 August. The SW dome grew and shed material down the flanks, increasing in height by just 3 m overall. On 25 August the volume of the SW dome was estimated at 1.4 million cubic meters and the summit lava dome was stable at an estimated 2.831 million cubic meters. A total of two pyroclastic flows descended the SW flank as far as 2 km; as many as 211 lava avalanches traveled a maximum of 2 km SW. Based on satellite images the Darwin VAAC noted that during 28-29 August ash plumes rose to 3-3.7 km (10,000-12,000 ft) a.s.l. and drifted SW, W, and NW. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-5 km away from the summit based on location.
Sources: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG), Darwin Volcanic Ash Advisory Centre (VAAC)
Report for Nevado del Ruiz
Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that during 25-31 August seismicity at Nevado del Ruiz had generally decreased compared to the previous week. Deformation data indicated minor changes. Gas-and-steam emissions were sometimes visible in satellite data and webcam images rising as high as 1.2 km above the summit and drifting NW and W. These emissions sometimes contained ash; on 26 August an ash emission rose 490 m and drifted WNW. The Alert Level remained at 3 (Yellow; the second lowest level on a four-color scale).
Source: Servicio Geológico Colombiano (SGC)
Report for Rincon de la Vieja
OVSICORI-UNA reported that small eruptive events at Rincón de la Vieja were recorded at 1915, 2049, and 2053 on 26 August, though weather conditions prevented visual confirmation of emissions. A one-minute-long phreatic eruption was recorded at 1446 on 27 or 28 August and produced an eruption plume that rose 1 km above the crater rim.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
Report for Sabancaya
Instituto Geofísico del Perú (IGP) reported a daily average of 36 explosions at Sabancaya during 23-30 August. Gas-and-ash plumes rose as high as 3.5 km above the summit and drifted S, SW, N, and NE. Ten thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. Minor inflation continued to be detected near Hualca Hualca (4 km N). The Alert Level remained at Orange (the second highest level on a four-color scale) and the public were warned to stay outside of a 12-km radius.
Source: Instituto Geofísico del Perú (IGP)
Report for Semeru
PVMBG reported that at 0718 on 26 August an ash plume from Semeru rose 500 m above the summit and drifted SW. The Alert Level remained at 2 (on a scale of 1-4), with a general exclusion zone of 1 km and extensions to 5 km in the SSE sector.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Sheveluch
KVERT reported that the lava dome at Sheveluch continued to grow and produced hot lava avalanches during 20-27 August. A daily bright thermal anomaly was identified in satellite images and gas-and-steam plumes containing some ash drifted 307 km NE, E, and SE. At 1100 on 29 August an ash plume 14x15 km in dimension drifted 30 km W at altitudes of 2.5-3 km (8,200-10,000 ft) a.s.l. On 28 August the Kamchatka Branch of Geophysical Services (KBGS; Russian Academy of Sciences) posted photos of the incandescent dome and avalanches, noting that small landslides and hot avalanches periodically traveled down the S and SE flanks of the dome. Larger landslides were observed 2-4 times per night. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Institute of Volcanology and Geodynamics, Russian Academy of Natural Science
Report for Sinabung
PVMBG reported that on most days during 25-31 August white gas-and-steam plumes from Sinabung rose as high as 500 m above the summit and drifted in multiple directions. Lava avalanches traveled 700 m down the flanks on 25 August. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Stromboli
INGV reported that during 23-29 August activity at Stromboli was characterized by ongoing explosive activity from three vents in Area N (North Crater area) and six vents in Area C-S (South-Central Crater area). Explosions from the N1 vent (Area N) ejected lapilli and bombs 80 m high, and produced minor ash emissions. Explosions at N2 vents (Area N) averaged 4-5 events per hour and ejected material 80 m high. Explosions from the S1 and S2 vents in Area C-S were sporadic and occurred at a rate of 5-12 per hour; coarse material was ejected 120 m high. Gas emissions rose from the C vent.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Suwanosejima
JMA reported that 15 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 3.2 km above the crater rim during 20-27 August. Large volcanic bombs were ejected 300 m from the crater. Crater incandescence was visible nightly and ashfall was often reported in Toshima village (4 km SSW); a large amount of ash fell in the village on 26 August. At 1231 on 28 August an eruption produced an ash plume that rose 4.8 km above the crater; weather clouds prevented clear views, though observations indicated that the event continued at least through 1700. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
Report for Yasur
On 26 August the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that seismic data and recent visual observations at Yasur confirmed ongoing explosions and gas-and-ash emissions. The Alert Level remained at 2 (on a scale of 0-4). VMGD reminded residents and tourists that hazardous areas were near and around the volcanic crater, within a 600-m-radius exclusion zone, and that volcanic ash and gas could reach areas impacted by trade winds.
Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD)