Smithsonian / USGS Weekly Volcanic Activity Report

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

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

Smithsonian / USGS Weekly Volcanic Activity Report for the week of 11 October-17 October 2023
Name	Location	Eruption Start Date	Report Status
Bezymianny	Central Kamchatka (Russia)	2016 Dec 5	New
Home Reef	Tonga Ridge	—	New
Klyuchevskoy	Central Kamchatka (Russia)	—	New
Aira	Kyushu (Japan)	2017 Mar 25	Continuing
Colima	Mexico	—	Continuing
Fuego	South-Central Guatemala	2002 Jan 4	Continuing
Great Sitkin	Andreanof Islands (USA)	2021 May 25	Continuing
Lewotolok	Lembata Island	2020 Nov 27	Continuing
Mayon	Luzon (Philippines)	2023 Apr 27 ± 2 days	Continuing
Merapi	Central Java	2020 Dec 31	Continuing
Popocatepetl	Mexico	2005 Jan 9	Continuing
Reventador	Ecuador	2008 Jul 27	Continuing
Sangay	Ecuador	2019 Mar 26	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)	—	Continuing
Suwanosejima	Ryukyu Islands (Japan)	2004 Oct 23	Continuing
Taal	Luzon (Philippines)	2024 Apr 12	Continuing
Villarrica	Central Chile	2014 Dec 2 ± 7 days	Continuing
Wrangell	Eastern Alaska	—	Continuing

All times are local unless otherwise stated.

Bezymianny | 11 October-17 October 2023 | New Activity / Unrest Cite this Report

Bezymianny
Central Kamchatka (Russia)

KVERT reported that activity at Bezymianny was significantly elevated during 0700-0830 on 17 October and was characterized by large collapses on the E flanks of the lava dome based on satellite and webcam images. These collapses generated hot avalanches of material and produced ash-and-gas plumes that rose as high as 3.5 km a.s.l. and drifted 15 km NE. At 1419 the Aviation Color Code was raised to Orange (the third level on a four-color scale). Lava extrusion continued at least through 1727 and ash plumes had drifted as far as 86 km NE. All times are local.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Home Reef | 11 October-17 October 2023 | New Activity / Unrest Cite this Report

Home Reef
Tonga Ridge

The Tonga Geological Services reported that Home Reef was erupting with a total of 11 eruptive events detected in satellite data during 12-17 October. On 14 October the Aviation Color Code was Yellow and the Hazard Alert was Orange; on 17 October the Aviation Color Code was lowered to Green and the Hazard Alert was lowered to Yellow, though mariners continued to be advised to stay 4 km away from the island. According to the Wellington VAAC a pilot observed an ash plume below 300 m (1,000 ft) a.s.l. in the vicinity of the volcano on 17 October, though the Tonga Meteorological Services stated that the emissions were mainly composed of steam. The most recent dimensions of the island were estimated to be about 424 m N-S and 223 m E-W, with an approximate total surface area of 17 acres, based on a 10 October satellite image. The island had steep headlands on the E half and a more gradual slope on the W half.

Sources: Tonga Geological Services, Government of Tonga, Wellington Volcanic Ash Advisory Center (VAAC)

Klyuchevskoy | 11 October-17 October 2023 | New Activity / Unrest Cite this Report

Klyuchevskoy
Central Kamchatka (Russia)

KVERT reported that the Strombolian eruption at Klyuchevskoy continued during 11-16 October and fed lava flows the descended the Apakhonchichsky drainage on the SE flank. Activity was notable during 11-12 October, characterized by the presence of ash in gas-and-steam plumes and an increase in the lava effusion rate. KVERT raised the Aviation Color Code to Orange (the third level on a four-color scale) as a result. According to observers at the Kamchatka Volcanological Station, lava effusion was almost continuous and incandescent material was ejected as high as 300 m above the crater rim. On 16 October lava on the SE flank melted snow and ice, causing phreatic explosions and large collapses of material from the margins of the flow. Dates and times are in UTC; specific events are in local time where noted.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Kamchatka Volcanological Station

Aira | 11 October-17 October 2023 | Continuing ActivityCite this Report

Aira
Kyushu (Japan)

JMA reported ongoing activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 9-16 October, with incandescence at the crater observed nightly. During the week there were a total of 18 eruptive events and 18 explosions. Ash plumes rose as high as 2.6 km above the crater rim and large blocks were ejected 800-900 m from the vent. 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)

Colima | 11 October-17 October 2023 | Continuing ActivityCite this Report

Colima
Mexico

On 13 October the Centro Universitario de Estudios Vulcanológicos (CUEV) - Universidad de Colima reported that during the previous week three lahars descended the Zarco (WSW), Montegrande (S), and La Arena drainages, triggered by Hurricane Lidia. In general, steam-and-gas emissions were low and rose from the NE part of the crater.

Source: Centro Universitario de Estudios Vulcanológicos (CUEV) - Universidad de Colima

Fuego | 11 October-17 October 2023 | Continuing ActivityCite this Report

Fuego
South-Central Guatemala

INSIVUMEH reported that, in general, 3-9 explosions per hour were recorded at Fuego during 10-17 October, though the rate of explosions was not noted 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 mainly SW, W, NW, and N. Minor ashfall was reported on a few of the days in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), Sangre de Cristo (8 km W), Acatenango (8 km E), San Pedro Yepocapa (8 km NW), La Soledad (7 km N), La Rochela (8 km SSW), and Las Palmas. Weak 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 some of the days. In the afternoon of 11 October lahars descended the Las Lajas, El Jute, and Ceniza drainages, carrying tree branches, trunks, and blocks as large as 1.5 m in diameter.

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

Great Sitkin | 11 October-17 October 2023 | Continuing ActivityCite this Report

Great Sitkin
Andreanof Islands (USA)

AVO reported that slow lava effusion likely continued at Great Sitkin during 10-17 October and was confirmed by radar data on 15 October. A thick flow in the summit crater mainly expanded E. Weakly elevated surface temperatures were identified in satellite data during 10-11 October. Seismicity was low and only a couple of earthquakes were detected during 15-16 October. Weather clouds often obscured satellite and webcam 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)

Lewotolok | 11 October-17 October 2023 | Continuing ActivityCite this Report

Lewotolok
Lembata Island

PVMBG reported that the eruption at Lewotolok continued during 11-17 October. White-and-gray ash plumes rose as high as 400 m above the summit and W, NW, and E during 11-12 and 14 October. On the other days during the week white steam-and-gas plumes rose as high as 500 m and drifted NW. At 2047 on 14 October a webcam image captured incandescent material that was ejected above the summit. 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)

Mayon | 11 October-17 October 2023 | Continuing ActivityCite this Report

Mayon
Luzon (Philippines)

PHIVOLCS reported that slow lava effusion at Mayon’s summit crater continued during 11-17 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 incandescent rockfalls and occasional pyroclastic density currents (PDCs, or pyroclastic flows) that descended the flanks as far as 4 km. Each day seismic stations recorded 100-126 rockfall events and 1-3 PDC events. There were 1-2 daily volcanic earthquakes during 10-14 October, and 26-37 daily volcanic earthquakes during 15-17 October that also included 24-32 tremor events that lasted 1-32 minutes each. Sulfur dioxide emissions measured almost daily averaged between 797 and 1,255 tonnes per day, with the highest value recorded on 12 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)

Merapi | 11 October-17 October 2023 | Continuing ActivityCite this Report

Merapi
Central Java

BPPTKG reported that the eruption at Merapi (on Java) continued during 6-12 October and seismicity remained at elevated levels. The SW lava dome produced a total of 163 lava avalanches that descended the S and SW flanks; 18 traveled as far as 1.6 km down the upper part of the Boyong drainage and 145 traveled as far as 2 km down the upper Bebeng drainage. Morphological changes to the SW lava dome were due to continuous 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)

Popocatepetl | 11 October-17 October 2023 | Continuing ActivityCite this Report

Popocatepetl
Mexico

CENAPRED reported that eruptive activity continued at Popocatépetl during 10-17 October. Long-period events totaling 87-402 per day were accompanied by steam-and-gas plumes that sometimes contained minor amounts of ash. Some of the plumes drifted NW and W, though cloudy weather conditions sometimes prevented visual observations. Periods of low-amplitude and high-frequency volcanic tremor were recorded daily, each lasting 23-462 minutes. According to the Washington VAAC, a large, discrete ash plume was identified in a satellite image at 1026 on 12 October rising to 6.7 km (22,000 ft) a.s.l. and drifting NE. A thermal anomaly was also visible. A minor explosion was recorded at 0405 on 13 October by the seismic network; the VAAC reported that an ash plume was seen in satellite and webcam images at 0421 drifting almost 30 km N at an altitude of 6.1 km (20,000 ft) a.s.l. A satellite image from 0101 on 14 October showed ash fanning out to the NW at 6.7 km a.s.l. and an image from 0701 showed a continuously emitted ash plume drifting WNW and NW at the same altitude; the VAAC noted that the webcam was not operational. CENAPRED stated that a moderate explosion was recorded at 1419 on 14 October. Video taken by observers and posted on social media showed a dark ash plume rising from the volcano. At 1831 on 14 October ash emissions were ongoing and visible in webcam and satellite images drifting WNW and NW according to the VAAC. At 0626 on 15 October an ash plume was visible in satellite and webcam images slowly drifting W at an altitude of 6.4 km (21,000 ft) a.s.l. The Alert Level remained at Yellow, Phase Two (the second level on a three-color scale) and the public was warned to stay 12 km away from the crater.

Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), El Informante

Reventador | 11 October-17 October 2023 | Continuing ActivityCite this Report

Reventador
Ecuador

IG-EPN reported that the eruption at Reventador was ongoing during 10-17 October. Seismicity was characterized by 15-43 daily explosions, long-period earthquakes, harmonic tremor, and tremor associated with emissions. Several daily ash-and-gas plumes rose as high as 1.3 km above the crater rim and drifted in multiple directions. Daily crater incandescence was visible during both overnight and morning hours. Incandescent material was ejected as high as 600 m above the crater rim several times during 10-11 October. Avalanches of incandescent material descended the flanks, concentrating down the SE flank during the beginning of the week, and traveling as far as 800 m from the summit. Weather conditions sometimes prevented views of the volcano. Secretaría de Gestión de Riesgos maintained the Alert Level at Orange (the second highest level on a four-color scale).

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Secretaría de Gestión de Riesgos (SGR)

Sangay | 11 October-17 October 2023 | Continuing ActivityCite this Report

Sangay
Ecuador

IG-EPN reported a high level of eruptive activity at Sangay during 10-17 October, with seismic stations recording 292-802 daily explosions. Several daily ash-and-gas plumes rose as high as 1.5 km above the crater rim and drifted N, NW, W, and SW. During overnight and morning hours webcam images showed incandescent material descending the SE flank as far as 1.8 km from the crater several times daily during overnight and early morning hours. Incandescence at the crater was often visible; incandescent material was ejected 500 m above the crater rim during 10-11 October. Secretaría de Gestión de Riesgos maintained the Alert Level at Yellow (the second highest level on a four-color scale).

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Secretaría de Gestión de Riesgos (SGR)

Santa Maria | 11 October-17 October 2023 | Continuing ActivityCite this Report

Santa Maria
Southwestern Guatemala

INSIVUMEH reported that eruptive activity continued at Santa Maria’s Santiaguito lava dome complex during 11-17 October with lava extrusion at Caliente dome. Incandescence from the dome was visible during most nights and early mornings, and occasionally from the lava flow on the WSW flank. Explosions triggered incandescent avalanches that descended the dome’s flanks in all directions. Block avalanches descended drainages on the SW, S, SE, and E flanks; during 12-13 and 16-17 October the avalanches were occasionally accompanied by small pyroclastic flows. Daily weak-to-moderate explosions generated gas-and-ash plumes that rose 800-1,000 m above the dome and drifted in multiple directions. During 13-14 October explosions occurred at a rate of 1-2 per hour and produced block-and-ash flows that descended the SW, S, and SE flanks and left gray ash deposits.

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

Semeru | 11 October-17 October 2023 | Continuing ActivityCite this Report

Semeru
Eastern Java

PVMBG reported that eruptive activity continued at Semeru during 11-17 October, though weather conditions sometimes prevented visual observations. White-and-gray ash plumes rose 200-700 m above the summit and drifted N, SE, S, and SW during 11-12 and 14-17 October. 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)

Sheveluch | 11 October-17 October 2023 | Continuing ActivityCite this Report

Sheveluch
Central Kamchatka (Russia)

KVERT reported that the eruption at Sheveluch continued during 5-12 October. A daily thermal anomaly was identified in satellite images and a plume of resuspended ash drifted 90 km ESE on 11 October. 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)

Shishaldin | 11 October-17 October 2023 | Continuing ActivityCite this Report

Shishaldin
Fox Islands (USA)

AVO reported that activity at Shishaldin during 10-17 October was characterized by daily sulfur dioxide gas emissions (except on 12 October) and frequent small earthquakes. Daily elevated surface temperatures were identified in satellite images. Steam-and-gas plumes observed in webcam images were reported each day, though weather conditions occasionally prevented views. The emissions were robust during 14-16 October, likely generated by the interaction of hot material and snow and ice. 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)

Suwanosejima | 11 October-17 October 2023 | Continuing ActivityCite this Report

Suwanosejima
Ryukyu Islands (Japan)

JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 9-16 October and crater incandescence was visible nightly. During 11-12 and 16 October eruptive events generated plumes that rose as high as 1.5 km above the crater rim and drifted W, SW, and SE, and ejected large blocks as far as 400 m from the vent. A total of eight explosions were recorded by the seismic network at 1522 on 14 October, at 0337, 0433, 0555, 1008, and 1539 on 15 October, and at 0454 and 0517 on 16 October. Ash plumes from the explosions rose as high as 900 m and drifted SE. Ash fell in Toshima village (3.5 km SSW). 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)

Taal | 11 October-17 October 2023 | Continuing ActivityCite this Report

Taal
Luzon (Philippines)

PHIVOLCS reported increased and continuous gas emissions at Taal in a special report issued on 12 October. Pronounced upwelling of gasses and hot fluids in the lake produced short plumes that drifted SW. Sulfur dioxide emissions were as high as 9,762 tonnes per day (t/d), the highest measurement recorded in 2023; emissions in September and October averaged 3,781 t/d. These upwellings in the lake continued during 14-16 October and sulfur dioxide emissions averaged 4,878 t/d on 14 October. The Alert Level remained at 1 (on a scale of 0-5), and PHIVOLCS reminded the public that the entire Taal Volcano Island was a Permanent Danger Zone (PDZ).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

Villarrica | 11 October-17 October 2023 | Continuing ActivityCite this Report

Villarrica
Central Chile

POVI reported that Strombolian activity at Villarrica continued to be observed in webcam images during 11-16 October. Lava fountains were observed during 11-12 October; incandescent material was ejected as high as 125 m above the crater rim and incandescent bombs were ejected onto the upper flanks. Strombolian explosions were less vigorous during 12-16 October with ballistics rising no higher than 100 m above the crater rim. Some incandescent material was ejected onto the upper N flank during 15-16 October. According to SERNAGEOMIN, the Alert Level remained at Yellow (the third level on a four-level scale) and the public was warned to stay 2 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: Proyecto Observación Villarrica Internet (POVI), Servicio Nacional de Geología y Minería (SERNAGEOMIN), Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres (SENAPRED)

Wrangell | 11 October-17 October 2023 | Continuing ActivityCite this Report

Wrangell
Eastern Alaska

On 13 October AVO changed both the Aviation Color Code and the Volcano Alert Level for Wrangell to Unassigned because of a station outage and the inability to reliably detect unrest at the volcano. AVO will continue using satellite, regional infrasound, and lightning data, and reports from pilots and ground observers to detect signs of eruptive activity.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Weekly Reports Archive

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Criteria & Disclaimers

Criteria

The Weekly Volcanic Activity Report does not necessarily include all volcanic activity that occurred on Earth during the week. More than a dozen volcanoes globally have displayed more-or-less continuous eruptive activity for decades or longer, and such routine activity is typically not reported here. Moreover, Earth's sea-floor volcanism is seldom reported even though in theory it represents the single most prolific source of erupted material. The Weekly Volcanic Activity Report summarizes volcanic activity that meets one or more of the following criteria:

- A volcano observatory raises or lowers the alert level at the volcano.
- A volcanic ash advisory has been released by a volcanic ash advisory center (VAAC) stating that an ash cloud has been produced from the volcano.
- A verifiable news report of new activity or a change in activity at the volcano has been issued.
- Observers have reported a significant change in volcanic activity. Such activity can include, but is not restricted to, pyroclastic flows, lahars, lava flows, dome collapse, or increased unrest.

Volcanoes are included in the "New Activity/Unrest" section of the Weekly Volcanic Activity Report if the activity occurs after at least 3 months of quiescence. Once a volcano is included in the "New Activity/Unrest" section, updates will remain in that section unless the activity continues for more than 1 month without escalating, after which time updates will be listed in the "Continuing Activity" section. Volcanoes are also included in the "New Activity/Unrest" section if the volcano is undergoing a period of relatively high unrest, or increasing unrest. This is commonly equal to Alert Level Orange on a scale of Green, Yellow, Orange, Red, where Red is the highest alert. Or alert level 3 on a scale of 1-4 or 1-5.

It is important to note that volcanic activity meeting one or more of these criteria may occur during the week, but may not be included in the Weekly Volcanic Activity Report because we did not receive a report.

Disclaimers

1. The Weekly Volcanic Activity Report is intended to provide timely information about global volcanism on a weekly basis. Consequently, the report is generated rapidly by summarizing volcanic reports from various sources, with little time for fact checking. The accuracy of the Weekly Volcanic Activity Report is dependent upon the quality of the volcanic activity reports we receive. Reports published in the Bulletin of the Global Volcanism Network are cover longer time periods and are more carefully reviewed, although all of the volcanoes discussed in the Weekly Volcanic Activity Report are not necessarily reported in the Bulletin. Because of our emphasis on rapid reporting on the web we have avoided diacritical marks. Reports are updated on the Weekly Volcanic Activity Report web page as they are received, therefore information may be included regarding events that occurred before the current report period.

2. Rapidly developing events lead to coverage that is often fragmentary. Volcanoes, their eruptions, and their plumes and associated atmospheric effects are complex phenomena that may require months to years of data analysis in order to create a comprehensive summary and interpretation of events.

3. Preliminary accounts sometimes contain exaggerations and "false alarms," and accordingly, this report may include some events ultimately found to be erroneous or misleading.

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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 Bezymianny
KVERT reported that activity at Bezymianny was significantly elevated during 0700-0830 on 17 October and was characterized by large collapses on the E flanks of the lava dome based on satellite and webcam images. These collapses generated hot avalanches of material and produced ash-and-gas plumes that rose as high as 3.5 km a.s.l. and drifted 15 km NE. At 1419 the Aviation Color Code was raised to Orange (the third level on a four-color scale). Lava extrusion continued at least through 1727 and ash plumes had drifted as far as 86 km NE. All times are local.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Report for Home Reef
The Tonga Geological Services reported that Home Reef was erupting with a total of 11 eruptive events detected in satellite data during 12-17 October. On 14 October the Aviation Color Code was Yellow and the Hazard Alert was Orange; on 17 October the Aviation Color Code was lowered to Green and the Hazard Alert was lowered to Yellow, though mariners continued to be advised to stay 4 km away from the island. According to the Wellington VAAC a pilot observed an ash plume below 300 m (1,000 ft) a.s.l. in the vicinity of the volcano on 17 October, though the Tonga Meteorological Services stated that the emissions were mainly composed of steam. The most recent dimensions of the island were estimated to be about 424 m N-S and 223 m E-W, with an approximate total surface area of 17 acres, based on a 10 October satellite image. The island had steep headlands on the E half and a more gradual slope on the W half.
Sources: Tonga Geological Services, Government of Tonga, Wellington Volcanic Ash Advisory Center (VAAC)

Report for Klyuchevskoy
KVERT reported that the Strombolian eruption at Klyuchevskoy continued during 11-16 October and fed lava flows the descended the Apakhonchichsky drainage on the SE flank. Activity was notable during 11-12 October, characterized by the presence of ash in gas-and-steam plumes and an increase in the lava effusion rate. KVERT raised the Aviation Color Code to Orange (the third level on a four-color scale) as a result. According to observers at the Kamchatka Volcanological Station, lava effusion was almost continuous and incandescent material was ejected as high as 300 m above the crater rim. On 16 October lava on the SE flank melted snow and ice, causing phreatic explosions and large collapses of material from the margins of the flow. Dates and times are in UTC; specific events are in local time where noted.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Kamchatka Volcanological Station

Report for Aira
JMA reported ongoing activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 9-16 October, with incandescence at the crater observed nightly. During the week there were a total of 18 eruptive events and 18 explosions. Ash plumes rose as high as 2.6 km above the crater rim and large blocks were ejected 800-900 m from the vent. 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 Colima
On 13 October the Centro Universitario de Estudios Vulcanológicos (CUEV) - Universidad de Colima reported that during the previous week three lahars descended the Zarco (WSW), Montegrande (S), and La Arena drainages, triggered by Hurricane Lidia. In general, steam-and-gas emissions were low and rose from the NE part of the crater.
Source: Centro Universitario de Estudios Vulcanológicos (CUEV) - Universidad de Colima

Report for Fuego
INSIVUMEH reported that, in general, 3-9 explosions per hour were recorded at Fuego during 10-17 October, though the rate of explosions was not noted 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 mainly SW, W, NW, and N. Minor ashfall was reported on a few of the days in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), Sangre de Cristo (8 km W), Acatenango (8 km E), San Pedro Yepocapa (8 km NW), La Soledad (7 km N), La Rochela (8 km SSW), and Las Palmas. Weak 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 some of the days. In the afternoon of 11 October lahars descended the Las Lajas, El Jute, and Ceniza drainages, carrying tree branches, trunks, and blocks as large as 1.5 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 10-17 October and was confirmed by radar data on 15 October. A thick flow in the summit crater mainly expanded E. Weakly elevated surface temperatures were identified in satellite data during 10-11 October. Seismicity was low and only a couple of earthquakes were detected during 15-16 October. Weather clouds often obscured satellite and webcam 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 Lewotolok
PVMBG reported that the eruption at Lewotolok continued during 11-17 October. White-and-gray ash plumes rose as high as 400 m above the summit and W, NW, and E during 11-12 and 14 October. On the other days during the week white steam-and-gas plumes rose as high as 500 m and drifted NW. At 2047 on 14 October a webcam image captured incandescent material that was ejected above the summit. 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 slow lava effusion at Mayon’s summit crater continued during 11-17 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 incandescent rockfalls and occasional pyroclastic density currents (PDCs, or pyroclastic flows) that descended the flanks as far as 4 km. Each day seismic stations recorded 100-126 rockfall events and 1-3 PDC events. There were 1-2 daily volcanic earthquakes during 10-14 October, and 26-37 daily volcanic earthquakes during 15-17 October that also included 24-32 tremor events that lasted 1-32 minutes each. Sulfur dioxide emissions measured almost daily averaged between 797 and 1,255 tonnes per day, with the highest value recorded on 12 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 6-12 October and seismicity remained at elevated levels. The SW lava dome produced a total of 163 lava avalanches that descended the S and SW flanks; 18 traveled as far as 1.6 km down the upper part of the Boyong drainage and 145 traveled as far as 2 km down the upper Bebeng drainage. Morphological changes to the SW lava dome were due to continuous 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 Popocatepetl
CENAPRED reported that eruptive activity continued at Popocatépetl during 10-17 October. Long-period events totaling 87-402 per day were accompanied by steam-and-gas plumes that sometimes contained minor amounts of ash. Some of the plumes drifted NW and W, though cloudy weather conditions sometimes prevented visual observations. Periods of low-amplitude and high-frequency volcanic tremor were recorded daily, each lasting 23-462 minutes. According to the Washington VAAC, a large, discrete ash plume was identified in a satellite image at 1026 on 12 October rising to 6.7 km (22,000 ft) a.s.l. and drifting NE. A thermal anomaly was also visible. A minor explosion was recorded at 0405 on 13 October by the seismic network; the VAAC reported that an ash plume was seen in satellite and webcam images at 0421 drifting almost 30 km N at an altitude of 6.1 km (20,000 ft) a.s.l. A satellite image from 0101 on 14 October showed ash fanning out to the NW at 6.7 km a.s.l. and an image from 0701 showed a continuously emitted ash plume drifting WNW and NW at the same altitude; the VAAC noted that the webcam was not operational. CENAPRED stated that a moderate explosion was recorded at 1419 on 14 October. Video taken by observers and posted on social media showed a dark ash plume rising from the volcano. At 1831 on 14 October ash emissions were ongoing and visible in webcam and satellite images drifting WNW and NW according to the VAAC. At 0626 on 15 October an ash plume was visible in satellite and webcam images slowly drifting W at an altitude of 6.4 km (21,000 ft) a.s.l. The Alert Level remained at Yellow, Phase Two (the second level on a three-color scale) and the public was warned to stay 12 km away from the crater.
Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), El Informante

Report for Reventador
IG-EPN reported that the eruption at Reventador was ongoing during 10-17 October. Seismicity was characterized by 15-43 daily explosions, long-period earthquakes, harmonic tremor, and tremor associated with emissions. Several daily ash-and-gas plumes rose as high as 1.3 km above the crater rim and drifted in multiple directions. Daily crater incandescence was visible during both overnight and morning hours. Incandescent material was ejected as high as 600 m above the crater rim several times during 10-11 October. Avalanches of incandescent material descended the flanks, concentrating down the SE flank during the beginning of the week, and traveling as far as 800 m from the summit. Weather conditions sometimes prevented views of the volcano. Secretaría de Gestión de Riesgos maintained the Alert Level at Orange (the second highest level on a four-color scale).
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Secretaría de Gestión de Riesgos (SGR)

Report for Sangay
IG-EPN reported a high level of eruptive activity at Sangay during 10-17 October, with seismic stations recording 292-802 daily explosions. Several daily ash-and-gas plumes rose as high as 1.5 km above the crater rim and drifted N, NW, W, and SW. During overnight and morning hours webcam images showed incandescent material descending the SE flank as far as 1.8 km from the crater several times daily during overnight and early morning hours. Incandescence at the crater was often visible; incandescent material was ejected 500 m above the crater rim during 10-11 October. Secretaría de Gestión de Riesgos maintained the Alert Level at Yellow (the second highest level on a four-color scale).
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Secretaría de Gestión de Riesgos (SGR)

Report for Santa Maria
INSIVUMEH reported that eruptive activity continued at Santa Maria’s Santiaguito lava dome complex during 11-17 October with lava extrusion at Caliente dome. Incandescence from the dome was visible during most nights and early mornings, and occasionally from the lava flow on the WSW flank. Explosions triggered incandescent avalanches that descended the dome’s flanks in all directions. Block avalanches descended drainages on the SW, S, SE, and E flanks; during 12-13 and 16-17 October the avalanches were occasionally accompanied by small pyroclastic flows. Daily weak-to-moderate explosions generated gas-and-ash plumes that rose 800-1,000 m above the dome and drifted in multiple directions. During 13-14 October explosions occurred at a rate of 1-2 per hour and produced block-and-ash flows that descended the SW, S, and SE flanks and left gray ash deposits.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Report for Semeru
PVMBG reported that eruptive activity continued at Semeru during 11-17 October, though weather conditions sometimes prevented visual observations. White-and-gray ash plumes rose 200-700 m above the summit and drifted N, SE, S, and SW during 11-12 and 14-17 October. 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 5-12 October. A daily thermal anomaly was identified in satellite images and a plume of resuspended ash drifted 90 km ESE on 11 October. 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 activity at Shishaldin during 10-17 October was characterized by daily sulfur dioxide gas emissions (except on 12 October) and frequent small earthquakes. Daily elevated surface temperatures were identified in satellite images. Steam-and-gas plumes observed in webcam images were reported each day, though weather conditions occasionally prevented views. The emissions were robust during 14-16 October, likely generated by the interaction of hot material and snow and ice. 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 Suwanosejima
JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 9-16 October and crater incandescence was visible nightly. During 11-12 and 16 October eruptive events generated plumes that rose as high as 1.5 km above the crater rim and drifted W, SW, and SE, and ejected large blocks as far as 400 m from the vent. A total of eight explosions were recorded by the seismic network at 1522 on 14 October, at 0337, 0433, 0555, 1008, and 1539 on 15 October, and at 0454 and 0517 on 16 October. Ash plumes from the explosions rose as high as 900 m and drifted SE. Ash fell in Toshima village (3.5 km SSW). 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 Taal
PHIVOLCS reported increased and continuous gas emissions at Taal in a special report issued on 12 October. Pronounced upwelling of gasses and hot fluids in the lake produced short plumes that drifted SW. Sulfur dioxide emissions were as high as 9,762 tonnes per day (t/d), the highest measurement recorded in 2023; emissions in September and October averaged 3,781 t/d. These upwellings in the lake continued during 14-16 October and sulfur dioxide emissions averaged 4,878 t/d on 14 October. The Alert Level remained at 1 (on a scale of 0-5), and PHIVOLCS reminded the public that the entire Taal Volcano Island was a Permanent Danger Zone (PDZ).
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

Report for Villarrica
POVI reported that Strombolian activity at Villarrica continued to be observed in webcam images during 11-16 October. Lava fountains were observed during 11-12 October; incandescent material was ejected as high as 125 m above the crater rim and incandescent bombs were ejected onto the upper flanks. Strombolian explosions were less vigorous during 12-16 October with ballistics rising no higher than 100 m above the crater rim. Some incandescent material was ejected onto the upper N flank during 15-16 October. According to SERNAGEOMIN, the Alert Level remained at Yellow (the third level on a four-level scale) and the public was warned to stay 2 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: Proyecto Observación Villarrica Internet (POVI), Servicio Nacional de Geología y Minería (SERNAGEOMIN), Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres (SENAPRED)

Report for Wrangell
On 13 October AVO changed both the Aviation Color Code and the Volcano Alert Level for Wrangell to Unassigned because of a station outage and the inability to reliably detect unrest at the volcano. AVO will continue using satellite, regional infrasound, and lightning data, and reports from pilots and ground observers to detect signs of eruptive activity.
Source: US Geological Survey Alaska Volcano Observatory (AVO)