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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 27 September-3 October 2023
Name Location Eruption Start Date Report Status
Villarrica Central Chile 2014 Dec 2 ± 7 days New
Aira Kyushu (Japan) 2017 Mar 25 Continuing
Ambae Vanuatu Continuing
East Epi Vanuatu Continuing
Ebeko Paramushir Island (Russia) 2022 Jun 11 Continuing
Fuego South-Central Guatemala 2002 Jan 4 Continuing
Great Sitkin Andreanof Islands (USA) 2021 May 25 Continuing
Klyuchevskoy Central Kamchatka (Russia) 2023 Jun 22 Continuing
Lewotolok Lembata Island 2020 Nov 27 Continuing
Mayon Luzon (Philippines) 2023 Apr 27 ± 2 days Continuing
Merapi Central Java 2020 Dec 31 Continuing
Nevado del Ruiz Colombia 2014 Nov 18 Continuing
Sabancaya Peru 2016 Nov 6 Continuing
Santa Maria Southwestern Guatemala 1922 Jun 22 Continuing
Semeru Eastern Java 2017 Jun 6 Continuing
Sheveluch Central Kamchatka (Russia) 1999 Aug 15 Continuing
Shishaldin Fox Islands (USA) 2023 Jul 12 Continuing
Slamet Central Java Continuing
Stromboli Aeolian Islands (Italy) 1934 Feb 2 Continuing
Suwanosejima Ryukyu Islands (Japan) 2004 Oct 23 Continuing
Ubinas Peru 2023 Jun 22 Continuing
Yasur Vanuatu 1270 ± 110 years Continuing
All times are local unless otherwise stated.
Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 19,832 individual reports over 1,207 weeks (average of 16 per week) on 332 different volcanoes.

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Agung Cuicocha Iliwerung Llaima Popocatepetl Sumbing
Ahyi Cumbal Inielika Lokon-Empung Purace Sundoro
Aira Dabbahu Ioto Lonquimay Puyehue-Cordon Caulle Suretamatai
Akan Davidof Irazu Lopevi Rabaul Suwanosejima
Alaid Dempo Iya Machin Raikoke Taal
Alu-Dalafilla Descabezado Grande Izu-Torishima Makushin Ranakah Tair, Jebel at
Ambae Dieng Volcanic Complex Jackson Segment Maly Semyachik Raoul Island Takawangha
Ambang Dukono Kaba Manam Rasshua Talang
Ambrym East Epi Kadovar Manda Hararo Raung Tambora
Anatahan Ebeko Kaitoku Seamount Marapi Redoubt Tanaga
Aniakchak Ebulobo Kama'ehuakanaloa Maroa Reventador Tandikat-Singgalang
Antillanca Volcanic Complex Edgecumbe Kambalny Martin Reykjanes Tangkoko-Duasudara
Antuco Egon Kanaga Masaya Rincon de la Vieja Tangkuban Parahu
Apoyeque Ekarma Kanlaon Maule, Laguna del Rinjani Tara, Batu
Arenal Eldey Karangetang Mauna Loa Ritter Island Ta'u
Asamayama Erebus Karkar Mayon Rotorua Taupo
Askja Erta Ale Karthala McDonald Islands Ruang Telica
Asosan Etna Karymsky Melimoyu Ruapehu Tenerife
Atka Volcanic Complex Etorofu-Yakeyama [Grozny Group] Kasatochi Merapi Ruby Tengger Caldera
Augustine Eyjafjallajokull Katla Midagahara Ruiz, Nevado del Three Sisters
Avachinsky Fagradalsfjall Katmai Misti, El Sabancaya Tinakula
Awu Fernandina Kavachi Miyakejima Sakar Tofua
Axial Seamount Fogo Kelimutu Momotombo Salak Tokachidake
Azul, Cerro Fonualei Kelud Monowai San Cristobal Tolbachik
Azumayama Fournaise, Piton de la Kerinci Montagu Island San Miguel Toliman
Bagana Fourpeaked Ketoi Moyorodake [Medvezhia] San Vicente Tongariro
Balbi Fuego Kharimkotan Mutnovsky Sangay Trident
Bamus Fujisan Kick 'em Jenny Myojinsho Sangeang Api Tungurahua
Banda Api Fukutoku-Oka-no-Ba Kie Besi Nabro Santa Ana Turrialba
Bardarbunga Galeras Kikai Negra, Sierra Santa Maria Ubinas
Barren Island Galunggung Kilauea Negro, Cerro Sao Jorge Ugashik-Peulik
Batur Gamalama Kirishimayama Nightingale Island Sarigan Ukinrek Maars
Bezymianny Gamkonora Kita-Ioto Nishinoshima Sarychev Peak Ulawun
Bogoslof Gareloi Kizimen Nisyros Saunders Unnamed
Brava Gaua Klyuchevskoy Novarupta Savo Unnamed
Bristol Island Gorely Kolokol Group NW Rota-1 Semeru Veniaminof
Bulusan Great Sitkin Koryaksky Nyamulagira Semisopochnoi Villarrica
Calbuco Grimsvotn Krakatau Nyiragongo Seulawah Agam Vulcano
Callaqui Guagua Pichincha Krummel-Garbuna-Welcker Ofu-Olosega Sheveluch West Mata
Cameroon Guallatiri Krysuvik-Trolladyngja Okataina Shishaldin Westdahl
Campi Flegrei del Mar di Sicilia Guntur Kuchinoerabujima Okmok Simbo Whakaari/White Island
Cayambe Hachijojima Kurikomayama Ontakesan Sinabung Witori
Chachadake [Tiatia] Hakoneyama Kusatsu-Shiranesan Oraefajokull Sinarka Wolf
Chaiten Heard Kverkfjoll Osorno Siple Wrangell
Chiginagak Hekla La Palma Pacaya Sirung Yakedake
Chikurachki Helgrindur Lamington Pagan Slamet Yasur
Chiles-Cerro Negro Hierro Lamongan Palena Volcanic Group Snaefellsjokull Yufu-Tsurumi
Chillan, Nevados de Hokkaido-Komagatake Langila Paluweh Soputan Zaozan [Zaosan]
Chirinkotan Home Reef Lanin Panarea Sorikmarapi Zavodovski
Chirpoi Hood Lascar Papandayan Sotara Zhupanovsky
Ciremai Huaynaputina Late Parker Soufriere Hills Zubair Group
Cleveland Hudson, Cerro Lateiki Pavlof Soufriere St. Vincent
Colima Huila, Nevado del Lengai, Ol Doinyo Pelee South Sarigan Seamount
Colo Hunga Tonga-Hunga Ha'apai Leroboleng Peuet Sague Spurr
Concepcion Ibu Lewotobi Pinatubo St. Helens
Copahue Ijen Lewotolok Planchon-Peteroa Stromboli
Cotopaxi Iliamna Little Sitkin Poas Sulu Range
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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 Villarrica
SERNAGEOMIN reported that the eruption in Villarrica’s summit crater continued during 26 September-3 October. Strombolian activity was observed almost nightly and largely confined to the crater, though sometimes material was ejected beyond the crater onto the upper flanks; weather conditions sometimes prevented visual observations of the summit. Satellite images from 26 September showed a spatter cone on the crater floor with one vent measuring 10 x 14 m, and a smaller vent about 35 m NE of the cone. During 26-27 September there were deposits of bombs around the upper flanks within 150 of the crater rim and several impact craters on the snow from explosive activity. Discrete emissions with low ash content were visible. Steam-and-gas emissions were visible during 27-28 September and tephra was ejected onto the upper NW flank. Steam-and-gas emissions sometimes contained ash during 28-29 September; a period of continuous ash emissions recorded during 1020-1250 on 29 September rose 60 m above the crater rim and drifted NW.

During an overflight on 29 September scientists observed lava in the vent and deposits of blocks in the crater. A satellite image showed ash deposits on the WNW flank as far as 3 km from the crater. Material was ejected from the crater several times during 29-30 September, with the emissions varying in duration and tephra content; notably, at 0740 on 30 September a pulsating ash plume rose 1.1 km above the crater rim and drifted NNW. Deposits on the S flank extended as far as 4.5 km from the crater rim as seen in 30 September satellite images. Steam-and-gas emissions with no or low ash content rose to lower heights on 1 October. Incandescence lit up the bases of two gas plumes, rising from the two vents, on 2 October, and dense white gas plumes rose as high as 300 m on 3 October. The Volcanic Alert Level remained at Orange (the third level on a four-level scale) and the public was warned to stay 8 km away from the crater. SENAPRED maintained the Alert Level at Yellow (the middle level on a three-color scale) for the communities of Villarrica, Pucón (16 km N), Curarrehue, and Panguipulli.
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres (SENAPRED)
Report for Aira
JMA reported ongoing activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 25 September-2 October and incandescence at the crater was observed nightly. Very small eruptive events were recorded during the week. Sulfur dioxide emissions were high, averaging 2,300 tons per day on 25 September. The geothermal areas on the SE flank of Minamidake and near the Showa Crater were observed during a field survey on 27 September. A very small eruptive event occurred at Showa on 28 September. 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 Ambae
On 28 September the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that steam-and-gas emissions at Ambae were ongoing based on satellite images. The Alert Level remained at 2 (on a scale of 0-5) and the public was warned to stay outside of the Danger Zone, defined as a 2-km radius around the active vents in Lake Voui, and away from drainages during heavy rains.
Source: Vanuatu Meteorology and Geohazards Department (VMGD)
Report for East Epi
On 28 September the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that minor unrest continued at Epi. Volcanic seismicity was sustained, though no surficial activity was observed. The Alert Level remained at 1 (on a scale of 0-5) and the public was warned to stay outside of the Danger Zone, defined as a 2-km radius around the active vent.
Source: Vanuatu Meteorology and Geohazards Department (VMGD)
Report for Ebeko
KVERT reported that moderate explosive activity at Ebeko was ongoing during 21-28 September. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 22, 24, and 27-28 September generated ash plumes that rose as high as 3 km (10,000 ft) a.s.l and drifted to the E. A thermal anomaly was identified in satellite images on 22 and 28 September; 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 in general 3-8 explosions per hour were recorded at Fuego during 26 September-3 October, though the rate was not determined on some of the days. The explosions generated ash-and-gas plumes that rose as high as 1.1 km above the crater rim and drifted as far as 30 km NW, W, and SW. Minor ashfall was reported in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), El Porvenir (8 km SE), Aldeas, and San Pedro Yepocapa (8 km NW). Rumbling was heard daily, and shock waves were occasionally detected. Explosions caused daily block avalanches to descend various drainages including the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Honda (E), and El Jute (ESE), and Las Lajas (SE). The explosions ejected incandescent material as high as 300 m above the summit on most days. In the early afternoon on 27 September lahars descended the Mineral and Seca drainages, carrying tree branches, trunks, and blocks as large as 1 m in diameter. In the early evening on that same day lahars descended the Las Lajas and Jute drainages, carrying tree branches, trunks, and blocks as large as 1.5 m in diameter. In the afternoon of 29 September a hot lahar traveled down the Ceniza, carrying blocks as large as 1.5 m as well as tree trunks and branches. On 30 September a lahar in the Ceniza transported trunks and branches and blocks up to 3 m in diameter.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Great Sitkin
AVO reported that slow lava effusion likely continued at Great Sitkin during 27 September-3 October, producing a thick flow in the summit crater that mainly expanded E. Seismicity was characterized as low with only a few daily earthquakes recorded by the seismic network. Weakly elevated surface temperatures were identified in satellite data during 2-3 October. Weather clouds sometimes obscured views. 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 Klyuchevskoy
KVERT reported that the explosive Strombolian eruption at Klyuchevskoy continued 21-28 September. The explosions produced variable amounts of ash. A daily bright thermal anomaly was identified in satellite images. Lava fountaining fed flows that advanced down the Apakhonchichsky and Kozyrevsky drainages on the SE flank. The Aviation Color Code remained at Yellow (the second 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 Lewotolok
PVMBG reported that the eruption at Lewotolok continued during 27 September-3 October. Daily white steam-and-gas plumes rose as high as 500 m above the summit and drifted W, NW, and E. Dense gray or white-and-gray ash plumes 600-700 m above the summit and drifted W during 28-29 September and 1 and 3 October. 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 26 September-3 October. 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 margins of the lava flows produced rockfalls and pyroclastic density currents (PDCs, or pyroclastic flows) that descended the flanks as far as 4 km. Each day seismic stations recorded 68-144 rockfall events, 1-3 PDC events, and 1-34 daily volcanic earthquakes. Two tremor events, each lasting one minute, were recorded during 27-28 September and 1-2 October. Sulfur dioxide emissions measured almost daily averaged between 716 and 1,593 tonnes per day, with the highest value recorded on 1 October. 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 22-28 September and seismicity remained at elevated levels. The SW lava dome produced a total of 171 lava avalanches that descended the S and SW flanks; 13 traveled as far as 1.5 km down the upper part of the Boyong drainage, 155 traveled as far as 2 km down the upper Bebeng drainage, and two traveled 1.6 km down the Sat/Putih drainage. One lava avalanche traveled 600 m down the Gendol drainage on the SE flank. Morphological changes to the SW lava dome were due to continuing collapses of material; based on thermal photos from 27 September and a drone overflight on 28 September the SW dome had grown slightly taller while the dome in the summit crater remained unchanged. The highest temperature measured at the SW dome was 409 degrees Celsius, lower than the previous measurement. At the central dome the highest temperature was 236 degrees Celsius, or near the temperatures of the surrounding rocks. 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 26 September-2 October. Seismicity indicating the movement of fluids was similar to the week before. The number of signals indicating rock fracturing significantly increased during 28-29 September. These events were located in areas 1-4 km S and SSE of Arenas Crater at depths of 2-5 km. Earthquakes recorded at 0512 (M 3.5) and 0614 (M 3.8) on 28 September were felt by residents. Rock-fracturing earthquakes were at low levels on the other days. Seismicity was generally low. Several thermal anomalies in the crater were identified in satellite images. Ash-and-gas emissions continued during the week, with the highest plumes rising to 2 km above the crater rim on 30 September. Plumes drifted NW, W, and SW; ashfall was reported in Manizales (27 km NW) on 30 September. The Alert Level remained at Yellow, Level III (the second level on a four-level scale).
Source: Servicio Geológico Colombiano (SGC)
Report for Sabancaya
Instituto Geofísico del Perú (IGP) reported that the eruption at Sabancaya continued during 25 September-1 October with a daily average of 39 explosions. Gas-and-ash plumes rose as high as 3 km above the summit and drifted E, SE, S, and SW. A total of 12 thermal anomalies from the lava dome in the summit crater were detected using satellite data. Minor inflation was detected near the Hualca Hualca sector (4 km N). Sulfur dioxide emissions increased, averaging 2,039 tons per day on 1 October. 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 Santa Maria
INSIVUMEH reported that eruptive activity continued at Santa Maria’s Santiaguito lava dome complex during 26 September-3 October. Incandescence from Caliente dome was visible during most nights and early mornings, and occasionally from the lava flow on the SW flank. Lava extrusion continued and generated block avalanches on the SW, S, and E flanks. Daily weak-to-moderate explosions generated gas-and-ash plumes that rose 700-1,000 m above the dome and drifted mainly W and SW. Explosions triggered incandescent avalanches that descended the dome’s flanks in all directions. A special bulletin issued at 1300 on 27 September described a hot lahar with a sulfur odor that descended the Zanjón Seco drainage on the SW flank carrying blocks 1-2 m in diameter. About 40 minutes later a viscous lahar descended the Cabello de Ángel river, a tributary of the Nimá I, on the E flank, carrying volcanic blocks up to 1 m in diameter, tree trunks, and branches. During 29-30 September explosions occurred at a rate of 1-2 per hour and produced block-and-ash flows that descended the W and SW flanks and left deposits of gray ash. Block avalanches descended the SW, S, and SE flanks during 30 September-1 October and occasionally produced small pyroclastic flows.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Semeru
PVMBG reported that eruptive activity continued at Semeru during 27 September-3 October. White steam-and-gas plumes were visible rising as high as 200 m above the summit and drifting in multiple directions during 28-29 September and 1-3 October. Dense white-and-gray or brown-and-gray ash plumes rose generally 600-800 m above the summit and drifted SW, W, N, and NE, though during 30 September-1 October the plumes rose as high as 1.5 km. The Alert Level remained at 3 (third highest on a scale of 1-4). The public was warned to stay at least 5 km away from the summit in all directions, 13 km from the summit to the SE, 500 m from the banks of the Kobokan drainage as far as 17 km from the summit, and to avoid other drainages including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Sheveluch
KVERT reported that the eruption at Sheveluch continued during 21-28 September. Thermal anomalies were identified in satellite images during 22 and 27-28 September; observations on other days were obscured by weather clouds. 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 Shishaldin
AVO reported that the significant explosive eruption at Shishaldin that occurred on 25 September was the eleventh that had occurred since 14 July, and among the most impactful. Ashfall was reported in several communities downwind and flight cancellations occurred in the region. A large ash cloud quickly rose to 14 km (45,000 ft) a.s.l., produced at least 150 lightning strokes with thunder heard in False Pass, and drifted E along the Alaska Peninsula. Seismicity decreased notably near the end of the strong activity on 25 September and continued to decrease during 26 September-3 October. Satellite data from 26 September showed that significant collapses had occurred at the summit crater and hot, steaming, deposits from pyroclastic flows and lahars were present on all flanks, particularly to the ENE and WSW. A small ash cloud was visible in webcam images on 27 September, likely from a collapse at the summit cone. Elevated surface temperatures were intense during 27-28 September. Minor steaming at the summit crater and from an area on the upper flanks was visible in webcam images on 28 September. Weakly elevated surface temperatures were identified in satellite data during 30 September-1 October and a pilot reported steaming from the vent on 1 October.

Seismicity significantly increased starting at around 2100 on 2 October and around the same time satellite images showed an increase in surface temperature consistent with lava fountaining. Small hot avalanches of rock and lava descended the flank. A distinct increase in infrasound, seismicity, and lighting detections was followed by the identification of an ash plume at 12 km (40,000 ft) a.s.l. at 0520 on 3 October in satellite images. The Aviation Color Code was raised to Red (the highest color on a four-color scale) and the Volcano Alert Level was raised to Warning (the highest level on a four-level scale). By 0931 ash plumes were only rising to altitudes of 6.1-7.6 km (20,000-25,000 ft) a.s.l. and both seismicity and infrasound levels had decreased. At 1036 the Aviation Color Code was lowered to Orange and the Volcano Alert Level was lowered to Watch; seismic and infrasound activity were slightly above background levels and steaming at the summit was observed in webcam images.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Slamet
In a 2 October press release PVMBG noted recent inflation and increased seismicity at Slamet. In 2023 seismicity was dominated by earthquake signals indicating movement of fluids around the surface and gas emissions, and these signals averaged 168 per day. Gas emissions rose 25-300 m above the summit. During 24 September-1 October there the number of local tectonic earthquakes increased followed by an increase in tremor amplitude. Tiltmeter and Electronic Distance Measurement data from the Cilik station located at an elevation of 1,500 m showed inflation while another station (Buncis) showed deflation; the Jurangmangu station located at a lower elevation that Cilik showed no significant deformation pattern. The Alert Level remained at 1 (on a scale of 1-4) and the public was warned to stay outside a 1 km radius.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Stromboli
INGV reported that eruptive activity continued at Stromboli during 25 September-1 October. Webcam images showed Strombolian activity at three vents in Area N (two at N1 and one at N2), within the upper part of the Sciara del Fuoco, and from three vents in Area C-S (South-Central Crater) in the crater terrace. Explosions of variable intensities occurred at a rate of 7-13 per hour at Area N. Explosions at N2 ejected mainly coarse material (bombs and lapilli), sometimes mixed with ash, up to 150 m above the vents. Spattering occurred at N1 and was intense during 27-28 September, coinciding with the effusion of a lava flow. The flow was first visible at 1428 on 27 September as it moved out of Area N and onto the upper part of the Sciara del Fuoco. By 2107 on 28 September spattering had decreased and the flow was no longer being fed. Spattering again increased and at about 0833 on 3 October lava from Area N flowed onto the upper part of the Sciara del Fuoco.

High-intensity explosions in sector S2 (Area C-S) averaged 6-8 per hour from the vents, ejecting a mix of coarse material as high as 150 m. Material was deposited in a wide area along the crater terrace. Intense spattering was visible on 26 September. The Dipartimento della Protezione Civile maintained the Alert Level at Yellow (the second highest level on a four-level scale).
Sources: Sezione di Catania - Osservatorio Etneo (INGV), Dipartimento della Protezione Civile
Report for Suwanosejima
JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 25 September-2 October. Eruptive events on 25, 27, and 30 September, and 1-2 October, produced ash plumes that rose as high as 1.3 km above the crater rim and ejected blocks as far as 300 m from the crater. Crater incandescence was visible nightly. Ash emissions were continuous from 0510 to 0555 on 1 October. 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 25 September-1 October at low-to-moderate levels. There were daily averages of 129 volcano-tectonic earthquakes indicating rock fracturing and 52 long-period earthquakes signifying the movement of gas and magma. A period of continuous ash emissions began at 1656 on 1 October and lasted about 90 minutes; the ash plumes rose as high as 1 km above the crater rim and drifted more than 10 km E, S, and SW. 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.
Source: Instituto Geofísico del Perú (IGP)
Report for Yasur
On 28 September the Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur continued at a high level of “major unrest,” as defined by the Alert Level 2 status (the middle level on a scale of 0-4). Recent satellite observations indicated an increase in steam, gas, and ash emissions from the summit crater. Explosions continued, with some ejecting bombs that landed back in and around the crater. The public was reminded to not enter the restricted area within 600 m around the boundaries of the Permanent Exclusion Zone, defined by Danger Zone A on the hazard map.
Source: Vanuatu Meteorology and Geohazards Department (VMGD)