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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 23 August-29 August 2023
Name Country Volcanic Province Eruption Start Date Report Status
Dempo Indonesia Sunda Volcanic Arc — New
Shishaldin United States Aleutian Ridge Volcanic Arc — New
Aira Japan Ryukyu Volcanic Arc 2017 Mar 25 Continuing
Cleveland United States Aleutian Ridge Volcanic Arc — Continuing
Ebeko Russia Kuril Volcanic Arc 2022 Jun 11 Continuing
Fuego Guatemala Central America Volcanic Arc 2002 Jan 4 Continuing
Great Sitkin United States Aleutian Ridge Volcanic Arc 2021 May 25 Continuing
Karangetang Indonesia Sangihe Volcanic Arc — Continuing
Klyuchevskoy Russia Eastern Kamchatka Volcanic Arc — Continuing
Lewotolok Indonesia Sunda Volcanic Arc — Continuing
Mayon Philippines Eastern Philippine Volcanic Arc — Continuing
Merapi Indonesia Sunda Volcanic Arc 2020 Dec 31 Continuing
Nevado del Ruiz Colombia Northern Andean Volcanic Arc 2014 Nov 18 Continuing
Rincon de la Vieja Costa Rica Central America Volcanic Arc 2021 Jun 28 Continuing
Santa Maria Guatemala Central America Volcanic Arc 1922 Jun 22 Continuing
Sheveluch Russia Eastern Kamchatka Volcanic Arc 1999 Aug 15 Continuing
Suwanosejima Japan Ryukyu Volcanic Arc 2004 Oct 23 Continuing
Ubinas Peru Central Andean Volcanic Arc — Continuing
All times are local unless otherwise stated.
Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 20,652 individual reports over 1,244 weeks (average of 17 per week) on 338 different volcanoes.

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

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Report for Dempo
Webcam images of Dempo posted in the daily PVMBG reports showed possible patches of discolored water or material floating on the surface of the crater lake during 27-29 August. The Aviation Color Code was raised to Orange (the third color on a four-color scale). The Alert Level remained at 2 (on a scale of 1-4), and the public were reminded to stay 1 km away from the crater and as far as 2 km on the N flank.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Shishaldin
AVO reported that the eruption at Shishaldin continued during 23-29 August. Low-level explosive activity likely continued during 23-24 August based on seismic and infrasound data. Elevated surface temperatures at the summit were identified in satellite data; webcam images were obscured by weather clouds. Seismic tremor began increasing at around 0300 on 25 August and was followed by elevated surface temperatures identified in satellite images, consistent with lava erupting at the summit. Small explosions were recorded in infrasound data. At 1204 AVO raised the Aviation Color Code to Red (the highest color on a four-color scale) and the Volcano Alert Level to Warning (the highest level on a four-level scale) in response to a pilot report of an ash plume at 8.5 km (28,000 ft) a.s.l. Seismicity peaked at 1630 and then began to rapidly decline at around 1730. Ash plumes rose as high as 10 km (32,000 ft) a.s.l. and drifted as far as 400 km NE. Ash plume altitudes began to decrease and by 2020 the plumes were rising as high 6.4 km (21,000 ft) a.s.l. and drifting NE. Ash emissions ended at 0000 on 26 August and seismicity was at low levels; AVO lowered the Aviation Color Code to Orange and the Volcano Alert Level to Watch. This large, ash-producing explosive event was the eighth to occur since the eruption started. Minor explosive activity within the summit crater was detected during 26-28 August and strongly elevated surface temperatures visible in satellite imagery. On 26 August a gas plume drifted NE. An AVO field crew working on Unimak Island observed a mass flow that descended the upper flanks beginning around 1720 on 27 August. The flow produced a short-lived ash cloud that rose to around 4.5 km (15,000 ft) a.s.l. and rapidly dissipated. The mass flow was likely caused by the collapse of lava spatter that had accumulated on the summit crater rim.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Aira
JMA reported ongoing activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 21-28 August. Very small eruptive events occasionally occurred at Minamidake and incandescence was observed at night. On 24 August sulfur dioxide emissions were extremely high at 3,300 tons per day. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 2 km away from both craters.
Source: Japan Meteorological Agency (JMA)
Report for Cleveland
AVO reported that seismicity at Cleveland had decreased over the previous few weeks to background levels. The Aviation Color Code was lowered to Green (the lowest color on a four-color scale) and the Volcano Alert Level was lowered to Normal (the lowest level on a four-level scale). Slightly elevated surface temperatures and diffuse gas emissions from the summit crater continued to occasionally be observed, or normal behavior for Cleveland. Monitoring capabilities had been upgraded to a five-station real-time seismic network, or enough stations to located volcanic earthquakes, based on an AVO partnership with the AVERT (Anticipating Volcanic Eruptions in Real-Time) project at Columbia University.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Ebeko
KVERT reported that moderate explosive activity at Ebeko was ongoing during 17-24 August. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 19-22 August generated ash plumes that rose as high as 3.5 km (11,500 ft) a.s.l and drifted to the E and SE. A thermal anomaly was identified in satellite images on 21 August; weather clouds obscured views on other days. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Report for Fuego
INSIVUMEH reported that 3-11 explosions per hour were recorded at Fuego during 9-15 August, generating ash-and-gas plumes that rose as high as 1.1 km above the crater rim. The ash plumes drifted as far as 30 km SW during 23-24 August, causing ashfall in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), and Palo Verde (10 km WSW). During 25-29 August the plumes drifted E, NE, and N, causing ashfall in multiple areas including Alotenango (8 km ENE), La Reunion, El Porvenir (8 km ENE), Antigua Guatemala (18 km NE), San Miguel Dueñas (10 km NE), and Ciudad Vieja (13.5 km NE). Daily shock waves rattled structures in communities around the volcano and rumbling was sometimes heard. Daily block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Honda, Las Lajas (SE), and El Jute (ESE) drainages. During 23-25 August explosions ejected incandescent material as high as 200 m above the summit. Lahars descended the Ceniza drainage on 29 August, transporting volcanic blocks up to 1.5 m in diameter, branches, and tree trunks.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Great Sitkin
AVO reported that slow lava effusion continued at Great Sitkin during 23-29 August, producing a thick flow in the summit crater. Seismicity remained slightly elevated throughout the week. Weather clouds often obscured satellite and webcam views, though slightly elevated surface temperatures and steaming from the lava flow were visible during 22-23 August. Steaming from the flow was again visible on 28 August. The Volcano Alert Level remained at Watch (the third level on a four-level scale) and the Aviation Color Code remained at Orange (the third color on a four-color scale).
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Karangetang
According to 17 and 18 August news articles a total of 39 families (104 people) were able to return to Tatahadeng and Tarorane villages because activity at Karangetang had declined. Incandescent avalanches continued to descend the SW, S, and SE flanks, though the number of events and the distanced traveled were lower. PVMBG reported that dense white gas-and-steam plumes were visible on most days rising as high as 150 m and drifting NE, N, and NW during 23-29 August. Weather clouds sometimes prevented views of the summit. Webcam images published in the reports showed incandescence at the summit and from material on the flanks of Main Crater (S crater). According to a news source, incandescent lava avalanches traveled as far as 1.5 km down the Batuawang drainage and 1.8 km down the Kahetang and Keting drainages. Incandescent material was sometimes ejected up to 25 m above the summit. The Alert Level remained at 3 (on a scale of 1-4) and the public were advised to stay 2.5 km away from Main Crater with an extension to 3.5 km on the S and SE flanks.
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Antara News, Antara News
Report for Klyuchevskoy
KVERT reported that the explosive Strombolian eruption at Klyuchevskoy continued during 17-24 August and a daily bright thermal anomaly was identified in satellite images. Lava advanced down the Apakhonchich drainage on the SE flank. The Aviation Color Code remained at Yellow (the second level on a four-color scale).
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Report for Lewotolok
PVMBG reported that the eruption at Lewotolok continued during 23-29 August. Daily white steam-and-gas plumes rose as high as 500 m above the summit and drifted W and NW, though the plumes in the webcam images in the reports appeared to contain ash. White-and-gray ash plumes rose as high as 500 m and drifted on 28 August. Volcano Observatory Notices for Aviation (VONAs) described ash plumes rising 700 m and drifting W and NW at 1409 on 23 August and 1603 on 24 August. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay at least 2 km away from the summit crater.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Mayon
PHIVOLCS reported that the eruption at Mayon continued during 23-29 August, with slow lava effusion from the summit crater feeding flows on the S, SE, and E flanks. The lengths of the lava flow in the Mi-Isi (S), Bonga (SE), and Basud (E) drainages remained at 2.8 km, 3.4 km, and 1.1 km, respectively. Collapses at the lava dome and from the lava flows produced incandescent rockfalls and pyroclastic density currents (PDCs, or pyroclastic flows) that descended the three drainages as far as 4 km. Each day seismic stations recorded 109-186 rockfall events and 1-6 PDC events. There were 2-56 daily volcanic earthquakes; those totals included 1-39 tremor events, each with durations of 1-36 minutes, during 23-27 August. Sulfur dioxide emissions were measured on a few days and averaged between 735 and 1,298 tonnes per day, with the highest value recorded on 26 August. The Alert Level remained at 3 (on a 0-5 scale) and residents were reminded to stay away from the 6-km-radius Permanent Danger Zone (PDZ). PHIVOLCS recommended that civil aviation authorities advise pilots to avoid flying close to the summit.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
Report for Merapi
BPPTKG reported that the eruption at Merapi (on Java) continued during 18-24 August and seismicity remained at elevated levels. The SW lava dome produced a total of 144 lava avalanches that descended the S and SW flanks; six traveled as far as 1.5 km down the upper part of the Boyong drainage and 138 traveled as far as 1.8 km down the upper Bebeng drainage. Morphological changes to the SW lava dome were due to continuing collapses of material. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km away from the summit based on location.
Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG)
Report for Nevado del Ruiz
Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that the eruption at Nevado del Ruiz continued at low-to-moderate levels during 22-28 August. Seismicity indicating the movement of fluids increased in number and magnitude compared to the week before; these seismic signals were most notable on 26 August and were associated with pulsating, or occasionally continuous, emissions of gas and ash. Seismicity indicating rock fracturing decreased compared to the previous week. These events were generally located below Arenas Crater and in areas within 8 km to the SE, NE, and NW at depths of less than 8 km. Ash-and-gas emissions continued, with the highest plumes rising as high as 1.3 and 2.6 km above the crater rim on 26 and at 1745 on 27 August, respectively. Plumes drifted NW, WNW, and SW and caused ashfall in Manizales (27 km NW) and Dosquebradas (40 km WSW) on 23 August, and on several other occasions during 26-28 August. The Alert Level remained at Yellow, Level III (the second level on a four-level scale).
Source: Servicio Geológico Colombiano (SGC)
Report for Rincon de la Vieja
OVSICORI-UNA reported that small phreatic events continued to be recorded at Rincón de la Vieja during 23-29 August. Four small events were recorded during 1900 om 24 August and 0828 on 25 August. The event at 0828 produced a steam-and-gas plume that rose 3 km above the crater rim and drifted NW. Four small events were also recorded during 27-28 August; the event at 0813 on 28 August lasted two minutes and generated a steam-and-gas plume that rose 2.5 km above the crater rim. The Alert Level remained at Level 3, Orange, the third level on a four-level scale.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
Report for Santa Maria
INSIVUMEH reported that eruptive activity continued at Santa Maria’s Santiaguito lava dome complex during 23-29 August. Incandescence from the dome was visible during most nights and early mornings, and occasionally from the SW lava flow. Lava extrusion continued and caused dome collapses and occasional short pyroclastic flows. Lava flows remained active in the Zanjón, Seco, and San Isidro drainages. Daily weak-to-moderate explosions generated gas-and-ash plumes that rose 700-1,000 m above the dome and drifted in multiple directions. Some explosions also triggered incandescent avalanches that descended the dome’s flanks in all directions, and into the Zanjón, Seco, and San Isidro drainages. Ashfall was reported in Belén (10 km S), Calaguache (9 km S), Santa María de Jesús (5 km SE) during 25-26 and 28-29 August.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Sheveluch
KVERT reported that the eruption at Sheveluch continued during 17-24 August. Intense fumarolic activity was visible at the active dome, and daily thermal anomalies were identified in satellite images. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Report for Suwanosejima
JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 21-28 August. Eruptive events produced volcanic plumes that rose as high as 1.4 km above the crater rim and produced ashfall in Toshima village (3.5 km SSW). Events at 0544, 0742, 0824, 1424, and 1704 on 25 August produced ash plumes that rose 1.1-1.2 km above the crater rim and drifted NE, W, and SW. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
Report for Ubinas
Instituto Geofísico del Perú (IGP) reported that the eruption at Ubinas continued during 22-27 August. There were daily averages of 229 volcano-tectonic earthquakes indicating rock fracturing and 54 long-period earthquakes signifying the movement of gas and magma. In addition, seismic signals associated with ash emissions were recorded for an average of eight hours per day, with a maximum of 17 hours on 26 August. An explosion at 1757 on 25 August generated an ash-and-gas plume that rose 4.2 km above the crater rim and drifted up to 25 km in multiple directions. According to the Buenos Aires VAAC diffuse ash-and-gas puffs, both daily and with periods of continuous emissions, reached 6.1-7.3 km (20,000-24,000 ft) a.s.l. (up to 1.6 km above the summit) and drifted multiple directions. The Alert Level remained at Orange (the third level on a four-color scale) and the public was warned to stay 4 km away from the crater.
Sources: Buenos Aires Volcanic Ash Advisory Center (VAAC), Instituto Geofísico del Perú (IGP)