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 18 October-24 October 2023
Name	Location	Eruption Start Date	Report Status
Bezymianny	Central Kamchatka (Russia)	2016 Dec 5	New
Bogoslof	Fox Islands (USA)	—	New
Home Reef	Tonga Ridge	—	New
Klyuchevskoy	Central Kamchatka (Russia)	—	New
Slamet	Central Java	—	New
Aira	Kyushu (Japan)	2017 Mar 25	Continuing
Bulusan	Luzon (Philippines)	—	Continuing
Ebeko	Paramushir Island (Russia)	2022 Jun 11	Continuing
Erta Ale	Ethiopia	1967 Jul 2 (in or before) ± 182 days	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
Nevado del Ruiz	Colombia	2014 Nov 18	Continuing
Sabancaya	Peru	2016 Nov 6	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
Ubinas	Peru	—	Continuing
Villarrica	Central Chile	2014 Dec 2 ± 7 days	Continuing

All times are local unless otherwise stated.

Bezymianny | 18 October-24 October 2023 | New Activity / Unrest Cite this Report

Bezymianny
Central Kamchatka (Russia)

KVERT reported that eruptive activity at Bezymianny continued during 18-23 October. Large collapses on the E flanks of the lava dome that began on 17 October continued the next day. A VONA issued at 1616 on 18 October described continuing large collapses and subsequent ash plumes that rose 4.5-5 km (14,800-16,400 ft) a.s.l. and drifted 32 km NW. A large explosion at 1630 produced ash plumes that rose 10-11 km (32,800-36,100 ft) a.s.l. and drifted 50 km NNE, prompting KVERT to raise the Aviation Color Code to Red (the highest level on a four-color scale). According to the Kamchatka Volcanological Station, inclement weather clouds hindered views of the volcano but a roar was heard at about 1650 and a dark ash cloud was visible. KVERT noted that by 2030 the ash cloud had detached and was 250 m long and 70 km wide; the cloud continued to drift NNE at an altitude of 8 km (26,200 ft) a.s.l. At 2117 the Aviation Color Code was lowered to Orange. Within two days, the ash cloud drifted NE and then NW as far as 850 km. Minor ashfall was reported in Kozyrevsk, 45 km W. At 0820 on 20 October an ash plume was identified in satellite images drifting 100 km ENE at altitudes of 4-4.5 km (13,100-14,800 ft) a.s.l. At 0903 the Aviation Color Code was lowered to Yellow. Lava effusion continued; fumarolic activity and dome incandescence were visible.

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

Bogoslof | 18 October-24 October 2023 | New Activity / Unrest Cite this Report

Bogoslof
Fox Islands (USA)

AVO raised the Volcano Alert Level for Bogoslof to Advisory (the second level on a four-level scale) and the Aviation Color Code to Yellow (the second color on a four-color scale) on 24 October due to increased seismicity. Over 90 earthquakes were detected in the vicinity of the volcano during the previous three days. No signs of unrest had been recorded in satellite data over the past several days.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Home Reef | 18 October-24 October 2023 | New Activity / Unrest Cite this Report

Home Reef
Tonga Ridge

The Tonga Geological Services reported that the eruption at Home Reef was ongoing. A total of 11 eruptive events were detected in satellite data during 16-19 October. A pilot observed an ash plume rising to 300 m at 1150 on 18 October. The Aviation Color Code remained at Yellow (the second level on a four-color scale) and mariners were advised to stay 4 km away from the island.

Source: Tonga Geological Services, Government of Tonga

Klyuchevskoy | 18 October-24 October 2023 | New Activity / Unrest Cite this Report

Klyuchevskoy
Central Kamchatka (Russia)

KVERT reported that the Strombolian eruption at Klyuchevskoy continued during 13-20 October and fed lava flows that descended the Apakhonchichsky drainage on the SE flank. Lava descended the Kozyrevsky drainage on 17 October. A daily bright thermal anomaly was identified in satellite images and plumes of resuspended ash rose to 6 km (19,700 ft) a.s.l. and drifted 430 km E. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates and times are in UTC; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Slamet | 18 October-24 October 2023 | New Activity / Unrest Cite this Report

Slamet
Central Java

PVMBG reported continuing inflation and increased seismicity at Slamet in a 19 October press release. An increase in the amplitude of a continuous tremor signal was recorded by the seismic network on 1 October and a period of harmonic tremor that lasted one hour and 18 minutes was recorded on 18 October. 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 than Cilik showed no significant deformation pattern. Inflation was recorded in tilt data at the Bambangan station (at 2,000 m elevation) during 11-18 October. Gas emissions rose 50-300 m above the summit. The Alert Level was raised to 2 (on a scale of 1-4) due to increasing activity and the public was warned to stay outside a 2 km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Aira | 18 October-24 October 2023 | Continuing ActivityCite this Report

Aira
Kyushu (Japan)

JMA reported ongoing activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 16-23 October, with incandescence at the crater observed nightly. Sulfur dioxide emissions were extremely high, averaging 4,200 tons per day on 16 October. During the week, there were a total of 11 eruptive events and 20 explosions, with a daily average of 1-5 explosions recorded during 16-21 October. Ash plumes rose as high as 3.6 km above the crater rim and drifted E, SE, and S, and large blocks were ejected as far as 1.2 km from the crater rim. A period of inflation began at around 0600 on 21 October, but ceased following an eruptive event during 0346-0430 on 24 October; the event produced an ash plume that rose 2.3 km above the crater rim and ejected large blocks 1.2 km. 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)

Bulusan | 18 October-24 October 2023 | Continuing ActivityCite this Report

Bulusan
Luzon (Philippines)

In a special advisory, PHIVOLCS reported that from 0500 on 14 October to 2100 on 22 October the seismic network at Bulusan recorded a total of 87 volcanic earthquakes. Out of those, 29 were volcano-tectonic events associated with rock fracturing, located at depths of 1-8 km beneath the S and W flanks of the volcano. Gas emissions from the summit crater were at weak-to-moderate levels; sulfur dioxide emissions averaged 241 tonnes per day on 19 October, near background levels. Ground deformation data from electronic tiltmeter stations continued to record inflation at the S flank since February 2023. The Alert Level remained at 0 (the lowest level on a scale of 0-5) and PHIVOLCS reminded the public not to enter the 4-km-radius Permanent Danger Zone (PDZ).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

Ebeko | 18 October-24 October 2023 | Continuing ActivityCite this Report

Ebeko
Paramushir Island (Russia)

KVERT reported that moderate explosive activity at Ebeko was ongoing during 13-20 October. A thermal anomaly was identified in satellite images on 14 October; weather clouds obscured views on other days. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions on 14 and 19 October generated ash plumes that rose as high as 4 km (13,100 ft) a.s.l and drifted to the E. 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)

Erta Ale | 18 October-24 October 2023 | Continuing ActivityCite this Report

Erta Ale
Ethiopia

An eruption at Erta Ale continued during 5-20 October based on satellite data. Four thermal anomalies were located in the N and S pit craters, aligned in a NW-SE direction, based on a 5 October image. The northernmost anomaly in the N pit crater, was relatively weak. The other three, one located at the SE rim of the N pit crater and two in the S pit crater, were brighter and likely represented spatter cones. These three anomalies were more intense in a 10 October image. An image on 15 October showed lava flows likely coming from the two cones in the S pit crater traveling SE, SSE, NE, and SW. Minor, linear anomalies to the N of the cone on the SE rim of the N pit crater likely represented lava flows. The flows had cooled by 20 October.

Source: Sentinel Hub

Great Sitkin | 18 October-24 October 2023 | Continuing ActivityCite this Report

Great Sitkin
Andreanof Islands (USA)

AVO reported that slow lava effusion at Great Sitkin was confirmed in satellite radar data on 17 October and likely continued during 18-24 October. A thick lava flow in the summit crater mainly expanded E. Seismicity was low and only a couple of earthquakes were detected during 17-19 October. Weather clouds sometimes 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 | 18 October-24 October 2023 | Continuing ActivityCite this Report

Lewotolok
Lembata Island

PVMBG reported that the eruption at Lewotolok continued during 18-24 October. White-and-gray ash plumes rose 400-600 m above the summit and W and NW during 19-21 and 23-24 October. White steam-and-gas plumes rose 200-300 m and drifted W and NW on the other days during the week. 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 | 18 October-24 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 43-175 rockfall events and 9-70 daily volcanic earthquakes including 2-67 tremor events that lasted as short as one minute to as long as about four and a half hours. Sulfur dioxide emissions measured near-daily averages between 727 and 1,521 tonnes per day, with the highest value recorded on 17 October. Short-lived bursts of gas were recorded in seismic and infrasound data at 1836 on 20 October and 0006 on 21 October. A period of increased lava effusion that started at 2210 on 21 October was characterized by more intense incandescence at the summit crater, followed by rockfalls and lava flows in the Mi-Isi and Bonga drainages. One PDC per day was recorded on 19, 21, and 22 October and two were recorded during 23-24 October; 53 were recorded during 24-25 October, accompanying a second period of increased effusion on 24 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 | 18 October-24 October 2023 | Continuing ActivityCite this Report

Merapi
Central Java

BPPTKG reported that the eruption at Merapi (on Java) continued during 13-19 October. The SW lava dome produced a total of 207 lava avalanches that descended the S and SW flanks; 54 traveled as far as 1.6 km down the upper part of the Boyong drainage, 151 traveled as far as 1.8 km down the upper Bebeng drainage, one traveled 1.5 km down the Sat/Putih drainage, and one traveled 800 m down the Senowo drainage. Morphological changes to the SW lava dome were due to continuous collapses of material. Seismicity remained at elevated levels and indicated increased magmatic activity at depths of less than 1.5 km below the summit. 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)

Nevado del Ruiz | 18 October-24 October 2023 | Continuing ActivityCite this Report

Nevado del Ruiz
Colombia

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 17-23 October. Seismic events indicating the movement of fluids increased in number and intensity compared to the previous week. The number of signals indicating rock fracturing increased in intensity, though decreased in number. These events were located in areas as far as 13 km ESE and SW of Arenas Crater, at depths less than one to 7 km. Earthquakes recorded at 2214 on 21 October (M 3) and at 0837 on 22 October (M 3.2) were felt by residents in the municipality of Murillo. Thermal anomalies on the crater floor were identified in satellite images, though they were less intense than the previous week. Several ash-and-gas emissions were visible during the week, with the highest plumes rising to 1.6 km above the crater rim on 17 October. Plumes drifted SW, NW, and NNE. The Alert Level remained at Yellow, Level III (the second level on a four-level scale).

Source: Servicio Geológico Colombiano (SGC)

Sabancaya | 18 October-24 October 2023 | Continuing ActivityCite this Report

Sabancaya
Peru

Instituto Geofísico del Perú (IGP) reported that the eruption at Sabancaya continued at moderate levels during 16-22 October with a daily average of six explosions. Gas-and-ash plumes rose as high as 2 km above the summit and drifted SE and S. A total of two 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). 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)

Semeru | 18 October-24 October 2023 | Continuing ActivityCite this Report

Semeru
Eastern Java

PVMBG reported that eruptive activity continued at Semeru during 18-24 October, though weather conditions sometimes prevented visual observations. Daily white-and-gray ash plumes rose 100-800 m above the summit and drifted in multiple directions. 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 | 18 October-24 October 2023 | Continuing ActivityCite this Report

Sheveluch
Central Kamchatka (Russia)

KVERT reported that the eruption at Sheveluch continued during 13-20 October and a daily thermal anomaly was 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)

Shishaldin | 18 October-24 October 2023 | Continuing ActivityCite this Report

Shishaldin
Fox Islands (USA)

AVO reported that activity at Shishaldin through 24 October had remained elevated since the last explosive event which occurred on 3 October. Sulfur dioxide emissions were elevated with daily averages of more than 1,000 tons per day based on satellite data; during periods in between previous explosive events, sulfur dioxide emissions were either low or were not detected. Abundant amounts of steam rose from the summit as well as from a liner feature that extended about 400 m from the summit down the NE flank. Seismicity remained elevated and was characterized by nearly constant seismic tremor and frequent, small, long-period, or low-frequency earthquakes. The seismicity was indicative of the movement of volcanic fluids and gases within the volcano and had been typically low in between previous explosive events. Daily elevated surface temperatures were identified in satellite data, though temperatures were inconsistent with lava at the surface. Pilots reported a prominent steam plume drifting 40 km WSW at altitudes of 3-4.6 km (10,000-15,000 ft) a.s.l. during the afternoon of 21 October. Minor steam emissions were visible in webcam images during 22-24 October. 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 | 18 October-24 October 2023 | Continuing ActivityCite this Report

Suwanosejima
Ryukyu Islands (Japan)

JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 16-23 October and crater incandescence was visible nightly. Eruptive events generated plumes that rose as high as 1.6 km above the crater rim and drifted S and SE and ejected large blocks as far as 400 m from the vent. Ash fell in Toshima village (3.5 km SSW). Explosions recorded at 0454 and 0517 on 16 October produced ash plumes that rose 500-600 m above the crater rim and drifted SE. During an overflight on 17 October scientists observed no notable changes in the crater and surrounding areas. 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)

Ubinas | 18 October-24 October 2023 | Continuing ActivityCite this Report

Ubinas
Peru

Instituto Geofísico del Perú (IGP) reported that the eruption at Ubinas continued during 16-22 October at low-to-moderate levels. There were daily averages of 204 volcano-tectonic earthquakes indicating rock fracturing and 25 long-period earthquakes signifying the movement of gas and magma. Steam-and-gas emissions rose as high as 1 km above the crater rim and drifted E and SE. 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)

Villarrica | 18 October-24 October 2023 | Continuing ActivityCite this Report

Villarrica
Central Chile

POVI reported that Strombolian activity and crater incandescence at Villarrica was observed in webcam images during 22-23 October, coinciding with the highest thermal radiance identified in Sentinel satellite data since July 2018. The Volcanic Alert level remained at Yellow (the third level on a four-level scale) according to SERNAGEOMIN 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)

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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 eruptive activity at Bezymianny continued during 18-23 October. Large collapses on the E flanks of the lava dome that began on 17 October continued the next day. A VONA issued at 1616 on 18 October described continuing large collapses and subsequent ash plumes that rose 4.5-5 km (14,800-16,400 ft) a.s.l. and drifted 32 km NW. A large explosion at 1630 produced ash plumes that rose 10-11 km (32,800-36,100 ft) a.s.l. and drifted 50 km NNE, prompting KVERT to raise the Aviation Color Code to Red (the highest level on a four-color scale). According to the Kamchatka Volcanological Station, inclement weather clouds hindered views of the volcano but a roar was heard at about 1650 and a dark ash cloud was visible. KVERT noted that by 2030 the ash cloud had detached and was 250 m long and 70 km wide; the cloud continued to drift NNE at an altitude of 8 km (26,200 ft) a.s.l. At 2117 the Aviation Color Code was lowered to Orange. Within two days, the ash cloud drifted NE and then NW as far as 850 km. Minor ashfall was reported in Kozyrevsk, 45 km W. At 0820 on 20 October an ash plume was identified in satellite images drifting 100 km ENE at altitudes of 4-4.5 km (13,100-14,800 ft) a.s.l. At 0903 the Aviation Color Code was lowered to Yellow. Lava effusion continued; fumarolic activity and dome incandescence were visible.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Kamchatka Volcanological Station

Report for Bogoslof
AVO raised the Volcano Alert Level for Bogoslof to Advisory (the second level on a four-level scale) and the Aviation Color Code to Yellow (the second color on a four-color scale) on 24 October due to increased seismicity. Over 90 earthquakes were detected in the vicinity of the volcano during the previous three days. No signs of unrest had been recorded in satellite data over the past several days.
Source: US Geological Survey Alaska Volcano Observatory (AVO)

Report for Home Reef
The Tonga Geological Services reported that the eruption at Home Reef was ongoing. A total of 11 eruptive events were detected in satellite data during 16-19 October. A pilot observed an ash plume rising to 300 m at 1150 on 18 October. The Aviation Color Code remained at Yellow (the second level on a four-color scale) and mariners were advised to stay 4 km away from the island.
Source: Tonga Geological Services, Government of Tonga

Report for Klyuchevskoy
KVERT reported that the Strombolian eruption at Klyuchevskoy continued during 13-20 October and fed lava flows that descended the Apakhonchichsky drainage on the SE flank. Lava descended the Kozyrevsky drainage on 17 October. A daily bright thermal anomaly was identified in satellite images and plumes of resuspended ash rose to 6 km (19,700 ft) a.s.l. and drifted 430 km E. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates and times are in UTC; specific events are in local time where noted.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Report for Slamet
PVMBG reported continuing inflation and increased seismicity at Slamet in a 19 October press release. An increase in the amplitude of a continuous tremor signal was recorded by the seismic network on 1 October and a period of harmonic tremor that lasted one hour and 18 minutes was recorded on 18 October. 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 than Cilik showed no significant deformation pattern. Inflation was recorded in tilt data at the Bambangan station (at 2,000 m elevation) during 11-18 October. Gas emissions rose 50-300 m above the summit. The Alert Level was raised to 2 (on a scale of 1-4) due to increasing activity and the public was warned to stay outside a 2 km radius.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Aira
JMA reported ongoing activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 16-23 October, with incandescence at the crater observed nightly. Sulfur dioxide emissions were extremely high, averaging 4,200 tons per day on 16 October. During the week, there were a total of 11 eruptive events and 20 explosions, with a daily average of 1-5 explosions recorded during 16-21 October. Ash plumes rose as high as 3.6 km above the crater rim and drifted E, SE, and S, and large blocks were ejected as far as 1.2 km from the crater rim. A period of inflation began at around 0600 on 21 October, but ceased following an eruptive event during 0346-0430 on 24 October; the event produced an ash plume that rose 2.3 km above the crater rim and ejected large blocks 1.2 km. 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 Bulusan
In a special advisory, PHIVOLCS reported that from 0500 on 14 October to 2100 on 22 October the seismic network at Bulusan recorded a total of 87 volcanic earthquakes. Out of those, 29 were volcano-tectonic events associated with rock fracturing, located at depths of 1-8 km beneath the S and W flanks of the volcano. Gas emissions from the summit crater were at weak-to-moderate levels; sulfur dioxide emissions averaged 241 tonnes per day on 19 October, near background levels. Ground deformation data from electronic tiltmeter stations continued to record inflation at the S flank since February 2023. The Alert Level remained at 0 (the lowest level on a scale of 0-5) and PHIVOLCS reminded the public not to enter the 4-km-radius Permanent Danger Zone (PDZ).
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

Report for Ebeko
KVERT reported that moderate explosive activity at Ebeko was ongoing during 13-20 October. A thermal anomaly was identified in satellite images on 14 October; weather clouds obscured views on other days. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions on 14 and 19 October generated ash plumes that rose as high as 4 km (13,100 ft) a.s.l and drifted to the E. 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 Erta Ale
An eruption at Erta Ale continued during 5-20 October based on satellite data. Four thermal anomalies were located in the N and S pit craters, aligned in a NW-SE direction, based on a 5 October image. The northernmost anomaly in the N pit crater, was relatively weak. The other three, one located at the SE rim of the N pit crater and two in the S pit crater, were brighter and likely represented spatter cones. These three anomalies were more intense in a 10 October image. An image on 15 October showed lava flows likely coming from the two cones in the S pit crater traveling SE, SSE, NE, and SW. Minor, linear anomalies to the N of the cone on the SE rim of the N pit crater likely represented lava flows. The flows had cooled by 20 October.
Source: Sentinel Hub

Report for Great Sitkin
AVO reported that slow lava effusion at Great Sitkin was confirmed in satellite radar data on 17 October and likely continued during 18-24 October. A thick lava flow in the summit crater mainly expanded E. Seismicity was low and only a couple of earthquakes were detected during 17-19 October. Weather clouds sometimes 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 18-24 October. White-and-gray ash plumes rose 400-600 m above the summit and W and NW during 19-21 and 23-24 October. White steam-and-gas plumes rose 200-300 m and drifted W and NW on the other days during the week. 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 43-175 rockfall events and 9-70 daily volcanic earthquakes including 2-67 tremor events that lasted as short as one minute to as long as about four and a half hours. Sulfur dioxide emissions measured near-daily averages between 727 and 1,521 tonnes per day, with the highest value recorded on 17 October. Short-lived bursts of gas were recorded in seismic and infrasound data at 1836 on 20 October and 0006 on 21 October. A period of increased lava effusion that started at 2210 on 21 October was characterized by more intense incandescence at the summit crater, followed by rockfalls and lava flows in the Mi-Isi and Bonga drainages. One PDC per day was recorded on 19, 21, and 22 October and two were recorded during 23-24 October; 53 were recorded during 24-25 October, accompanying a second period of increased effusion on 24 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 13-19 October. The SW lava dome produced a total of 207 lava avalanches that descended the S and SW flanks; 54 traveled as far as 1.6 km down the upper part of the Boyong drainage, 151 traveled as far as 1.8 km down the upper Bebeng drainage, one traveled 1.5 km down the Sat/Putih drainage, and one traveled 800 m down the Senowo drainage. Morphological changes to the SW lava dome were due to continuous collapses of material. Seismicity remained at elevated levels and indicated increased magmatic activity at depths of less than 1.5 km below the summit. 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 17-23 October. Seismic events indicating the movement of fluids increased in number and intensity compared to the previous week. The number of signals indicating rock fracturing increased in intensity, though decreased in number. These events were located in areas as far as 13 km ESE and SW of Arenas Crater, at depths less than one to 7 km. Earthquakes recorded at 2214 on 21 October (M 3) and at 0837 on 22 October (M 3.2) were felt by residents in the municipality of Murillo. Thermal anomalies on the crater floor were identified in satellite images, though they were less intense than the previous week. Several ash-and-gas emissions were visible during the week, with the highest plumes rising to 1.6 km above the crater rim on 17 October. Plumes drifted SW, NW, and NNE. 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 at moderate levels during 16-22 October with a daily average of six explosions. Gas-and-ash plumes rose as high as 2 km above the summit and drifted SE and S. A total of two 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). The Alert Level remained at Orange (the second highest level on a four-color scale) and the public were warned to stay outside of a 12 km radius.
Source: Instituto Geofísico del Perú (IGP)

Report for Semeru
PVMBG reported that eruptive activity continued at Semeru during 18-24 October, though weather conditions sometimes prevented visual observations. Daily white-and-gray ash plumes rose 100-800 m above the summit and drifted in multiple directions. 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 13-20 October and a daily thermal anomaly was 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 Shishaldin
AVO reported that activity at Shishaldin through 24 October had remained elevated since the last explosive event which occurred on 3 October. Sulfur dioxide emissions were elevated with daily averages of more than 1,000 tons per day based on satellite data; during periods in between previous explosive events, sulfur dioxide emissions were either low or were not detected. Abundant amounts of steam rose from the summit as well as from a liner feature that extended about 400 m from the summit down the NE flank. Seismicity remained elevated and was characterized by nearly constant seismic tremor and frequent, small, long-period, or low-frequency earthquakes. The seismicity was indicative of the movement of volcanic fluids and gases within the volcano and had been typically low in between previous explosive events. Daily elevated surface temperatures were identified in satellite data, though temperatures were inconsistent with lava at the surface. Pilots reported a prominent steam plume drifting 40 km WSW at altitudes of 3-4.6 km (10,000-15,000 ft) a.s.l. during the afternoon of 21 October. Minor steam emissions were visible in webcam images during 22-24 October. 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 16-23 October and crater incandescence was visible nightly. Eruptive events generated plumes that rose as high as 1.6 km above the crater rim and drifted S and SE and ejected large blocks as far as 400 m from the vent. Ash fell in Toshima village (3.5 km SSW). Explosions recorded at 0454 and 0517 on 16 October produced ash plumes that rose 500-600 m above the crater rim and drifted SE. During an overflight on 17 October scientists observed no notable changes in the crater and surrounding areas. 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 16-22 October at low-to-moderate levels. There were daily averages of 204 volcano-tectonic earthquakes indicating rock fracturing and 25 long-period earthquakes signifying the movement of gas and magma. Steam-and-gas emissions rose as high as 1 km above the crater rim and drifted E and SE. 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 Villarrica
POVI reported that Strombolian activity and crater incandescence at Villarrica was observed in webcam images during 22-23 October, coinciding with the highest thermal radiance identified in Sentinel satellite data since July 2018. The Volcanic Alert level remained at Yellow (the third level on a four-level scale) according to SERNAGEOMIN 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)