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 25 September-1 October 2019
Name	Location	Eruption Start Date	Report Status
Copahue	Central Chile-Argentina	—	New
Poas	Costa Rica	2023 Dec 1	New
Ulawun	New Britain (Papua New Guinea)	—	New
Aira	Kyushu (Japan)	2017 Mar 25	Continuing
Asosan	Kyushu (Japan)	—	Continuing
Dukono	Halmahera	1933 Aug 13	Continuing
Ebeko	Paramushir Island (Russia)	2022 Jun 11	Continuing
Etna	Sicily (Italy)	2022 Nov 27	Continuing
Ibu	Halmahera	2008 Apr 5	Continuing
Karangetang	Sangihe Islands	2018 Nov 25	Continuing
Karymsky	Eastern Kamchatka (Russia)	—	Continuing
Krakatau	Sunda Strait	—	Continuing
Manam	Northeast of New Guinea	2014 Jun 29	Continuing
Merapi	Central Java	2020 Dec 31	Continuing
Nevados de Chillan	Central Chile	—	Continuing
Popocatepetl	Mexico	2005 Jan 9	Continuing
Sabancaya	Peru	2016 Nov 6	Continuing
Sheveluch	Central Kamchatka (Russia)	1999 Aug 15	Continuing
Shishaldin	Fox Islands (USA)	2023 Jul 12	Continuing
Suwanosejima	Ryukyu Islands (Japan)	2004 Oct 23	Continuing
Tangkuban Parahu	Western Java	—	Continuing
Whakaari/White Island	North Island (New Zealand)	—	Continuing

All times are local unless otherwise stated.

Copahue | 25 September-1 October 2019 | New Activity / Unrest Cite this Report

Copahue
Central Chile-Argentina

On 30 September OVDAS-SERNAGEOMIN, ONEMI, and SEGEMAR reported that three long-period (LP) earthquakes with notable magnitudes were located about 5.8 km NE of Copahue’s El Agrio Crater. In addition, abundant LP and volcano-tectonic (VT) signals with relatively lower magnitudes were also located in the same area. Some of the events were felt by residents of Caviahue (10 km E) and Copahue 7 km NE) in Argentina. SERNAGEOMIN raised the Alert Level to Orange (second highest level on a four-color scale) and ONEMI updated the Yellow Alert (the middle level on a three-color scale) for residents, noting a restriction for entering a 5-km radius from El Agrio Crater. The seismic network recorded a local M 3.1 VT earthquake at 2340 on 30 September, and a local M 3.7 VT event at 0628 on 1 October. The report also noted that 14 lower-energy events (largest was M 2.4) were recorded.

Sources: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI), Servicio Nacional de Geología y Minería (SERNAGEOMIN), Servicio Geológico Minero Argentino (SEGEMAR)

Poas | 25 September-1 October 2019 | New Activity / Unrest Cite this Report

Poas
Costa Rica

OVSICORI-UNA reported that during 16-26 September sulfur dioxide emissions from Poás drifted W and NE, causing a sulfur odor in Alajuela, Heredia, San José, and Cartago. Acidic rain was recorded at the official’s house in the Poás Volcano National Park (PNVP) on 23 September and at Universidad Nacional Costa Rica (UNA) in Heredia on 26 September. At 0540 on 30 September a five-minute-long phreatic eruption ejected sediment, and produced a plume that rose 2 km above the crater rim and drifted SW. Ashfall and a sulfur odor was reported in Trojas de Sarchi and Grecia. Officials closed the PNVP because of the eruption and ongoing elevated seismicity; the park remained closed the next day.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA), Tico Times

Ulawun | 25 September-1 October 2019 | New Activity / Unrest Cite this Report

Ulawun
New Britain (Papua New Guinea)

RVO reported that small, discrete, volcano-tectonic earthquakes at Ulawun began occurring more regularly around 1000 on 30 September; by 1130 they were frequent and by 1220 they were characterized as a swarm. The magnitude of the events overall increased with time and some were felt by residents and accompanied by booming sounds. Events were less frequent and intense during 1730-1930. Sometime afterwards RSAM values erratically increased, reaching a high of 10,000 units between 0130 and 0200 on 1 October. The Alert Level was raised to Stage 2 (the second lowest level on a four-stage scale).

Periods of volcano-tectonic earthquakes slowly transformed into continuous tremor with distinct bursts of high-frequency signals marking discrete volcano-tectonic events during 0430-0500 on 1 October. During this time a new vent opened in a deep valley on the SSW flank at 700 m elevation. The eruption was described as a distinct incandescent glow formed from ejecting material rising less than 100 m above the vent. By dawn light-gray ash plumes were visible rising several hundred meters and drifting NW. Lava fountaining continued throughout the day, and gray ash plumes rose several kilometers above the vent and drifted W. RVO recommended that the Alert Level be raised to Stage 3. On 2 October lava fountains rose several hundred meters and ash-and-steam plumes rose to variable heights between 2 and 5 km, causing ashfall in Navo (W). A lava flow which emerged during the night traveled 1-2 km NW, though visibility was hindered due to weather conditions. Loud rumbling and roaring was noted. Seismicity remained high with RSAM values passing 12,000 units.

Source: Rabaul Volcano Observatory (RVO)

Aira | 25 September-1 October 2019 | Continuing ActivityCite this Report

Aira
Kyushu (Japan)

JMA reported that incandescence from Minamidake crater (at Aira Caldera’s Sakurajima volcano) was occasionally visible at night during 24-30 September. Very small eruptive events were recorded. The Alert Level remained at 3 (on a 5-level scale).

Source: Japan Meteorological Agency (JMA)

Asosan | 25 September-1 October 2019 | Continuing ActivityCite this Report

Asosan
Kyushu (Japan)

JMA reported that during 25-30 September ash plumes rose as high as 1.6 km above Asosan’s summit crater rim and drifted NE and NW, causing ashfall in areas downwind. The sulfur dioxide emission rate was 2,600 tons per day on 26 September. The Alert Level remained at 2 (on a scale of 1-5).

Source: Japan Meteorological Agency (JMA)

Dukono | 25 September-1 October 2019 | Continuing ActivityCite this Report

Dukono
Halmahera

Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 25 September-1 October ash plumes from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)

Ebeko | 25 September-1 October 2019 | Continuing ActivityCite this Report

Ebeko
Paramushir Island (Russia)

Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 22-23 September that sent ash plumes up to 3 km (10,000 ft) a.s.l. Ash plumes drifted E and NE, causing ashfall in Severo-Kurilsk. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Etna | 25 September-1 October 2019 | Continuing ActivityCite this Report

Etna
Sicily (Italy)

INGV reported that intense Strombolian activity from vents at the bottom of Etna’s Voragine Crater (VOR) continued during 23-29 September. Gas emissions from Northeast Crater (NEC) were intense and continuous, and ash plumes were occasionally visible and sometimes accompanied by incandescent flashes. A large ash emission rose from the crater on 27 September and drifted S.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

Ibu | 25 September-1 October 2019 | Continuing ActivityCite this Report

Ibu
Halmahera

The Darwin VAAC reported that on 28 September ash plumes from Ibu rose to altitudes of 1.8-2.1 km (6,00-7,000 ft) a.s.l. and drifted WNW based on satellite images and weather models. PVMBG reported that at 1806 on 30 September an ash plume rose about 800 m above the crater rim and drifted N. 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 active crater, and 3.5 km away on the N side.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Karangetang | 25 September-1 October 2019 | Continuing ActivityCite this Report

Karangetang
Sangihe Islands

PVMBG reported that during 25 September-1 October lava continued to effuse from Karangetang’s Main Crater (S), traveling as far as 1.5 km down the Nanitu, Pangi, and Sense drainages on the SW and W flanks. Sometimes dense white plumes rose to 300 m above the summit. On 27 and 29 September the Darwin VAAC noted that ash plumes rose to 2.1-2.4 km (7,000-8,000 ft) a.s.l. (about 330-640 m above the crater rim) and drifted SW and W. The Alert Level remained at 2 (on a scale of 1-4).

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

Karymsky | 25 September-1 October 2019 | Continuing ActivityCite this Report

Karymsky
Eastern Kamchatka (Russia)

KVERT reported that a thermal anomaly over Karymsky was visible in satellite images on 19 September. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Krakatau | 25 September-1 October 2019 | Continuing ActivityCite this Report

Krakatau
Sunda Strait

PVMBG reported that Anak Krakatau’s seismic network recorded 10 eruptive events during 23-29 September. A webcam at the summit recorded diffuse white plumes rising as high as 150 m from the vent at the bottom of the crater. Eruptive events recorded by the webcam at 0813 on 25 September, 0555 and 0835 on 26 September, and 1520 on 27 September generated dense gray-and-white ash plumes that rose 150-200 m from the vent and generally drifted N. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km-radius hazard zone from the crater.

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

Manam | 25 September-1 October 2019 | Continuing ActivityCite this Report

Manam
Northeast of New Guinea

The Darwin VAAC reported that on 29 September diffuse ash plumes from Manam rose to altitudes of 2.4-2.7 km (8,000-9,000 ft) a.s.l. and drifted W, based on satellite data and weather models. A sulfur dioxide signature in the plume was also detected. On 30 September RVO reported increased seismicity; the VAAC noted ongoing emissions and a persistent thermal anomaly.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Merapi | 25 September-1 October 2019 | Continuing ActivityCite this Report

Merapi
Central Java

PVMBG reported that the lava dome at Merapi slowly grew during 20-26 September and was an estimated 468,000 cubic meters, based on 19 September measurements based on drone photos. Extruded lava fell into the upper parts of the SE flank, generating three block-and-ash flows that traveled as far as 1.5 km down the Gendol drainage. Diffuse white plumes rose as high as 75 m above the summit. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to stay outside of the 3-km exclusion zone.

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

Nevados de Chillan | 25 September-1 October 2019 | Continuing ActivityCite this Report

Nevados de Chillan
Central Chile

ONEMI and SERNAGEOMIN reported that during 24 September-1 October white-to-gray gas plumes from Nevados de Chillán’s Nicanor Crater rose as high as 1.3 km above the rim and drifted NE, E, and SE. Explosions sometimes ejected incandescent material onto the flanks. A lava flow on the NNE flank continued to advance at a low rate. Ashfall was reported 15 km WNW in Las Trancas on 24 September. The Alert Level remained at Orange, the second highest level on a four-color scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-color scale) for the communities of Pinto, Coihueco, and San Fabián, and stated that the public should stay at least 3 km away from the crater on the SW flank and 5 km away on the ENE flank.

Sources: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI), Servicio Nacional de Geología y Minería (SERNAGEOMIN)

Popocatepetl | 25 September-1 October 2019 | Continuing ActivityCite this Report

Popocatepetl
Mexico

CENAPRED reported that each day during 25 September-1 October there were 123-224 steam-and-gas emissions from Popocatépetl, some of which contained ash. As many as 10 explosions were recorded each day and crater incandescence was sometimes visible at night. During an overflight on 27 September observatory staff, scientists, and civil protection staff observed a lava dome, 30 m in diameter, at the bottom of the inner crater. The inner crater was 350 m in diameter and 150 m deep based on thermal images and photographs. The Alert Level remained at Yellow, Phase Two (middle level on a three-color scale).

Source: Centro Nacional de Prevencion de Desastres (CENAPRED)

Sabancaya | 25 September-1 October 2019 | Continuing ActivityCite this Report

Sabancaya
Peru

Instituto Geofísico del Perú (IGP) reported that an average of 15 low-to-medium intensity explosions per day occurred at Sabancaya during 23-29 September. Gas-and-ash plumes rose as high as 1.7 km above the summit and drifted NW, W, and SW. There were 11 thermal anomalies identified in satellite data. 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)

Sheveluch | 25 September-1 October 2019 | Continuing ActivityCite this Report

Sheveluch
Central Kamchatka (Russia)

KVERT reported that a thermal anomaly over Sheveluch’s lava dome was identified daily in satellite images during 20-27 September. Explosions recorded during 20-21, 23, and 26 September produced ash plumes that rose to 7 km (23,000 ft) a.s.l. and drifted 580 km ESE. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Shishaldin | 25 September-1 October 2019 | Continuing ActivityCite this Report

Shishaldin
Fox Islands (USA)

On 26 September AVO reported that seismicity at Shishaldin had decreased during the previous few weeks to levels slightly above background. Satellite images indicated decreased surface temperatures at the summit over the same period and showed collapse and slumping of the floor of the summit crater, suggesting a withdrawal of magma. Tiltmeter data suggested that the collapse may have occurred on 19 September. The Aviation Color Code was lowered to Yellow and the Volcano Alert Level was lowered to Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Suwanosejima | 25 September-1 October 2019 | Continuing ActivityCite this Report

Suwanosejima
Ryukyu Islands (Japan)

JMA reported that during 20-27 September white plumes rose 800 m above the rim of Suwanosejima’s Ontake Crater and crater incandescence was visible at night. The Alert Level remained at 2 (on a 5-level scale).

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Tangkuban Parahu | 25 September-1 October 2019 | Continuing ActivityCite this Report

Tangkuban Parahu
Western Java

PVMBG reported that during 23-29 September diffuse white water vapor plumes rose 200 m above the vent on Tangkubanparahu's Ratu Crater floor. The seismic network recorded continuous tremor. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 1.5 km away from the active crater.

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

Whakaari/White Island | 25 September-1 October 2019 | Continuing ActivityCite this Report

Whakaari/White Island
North Island (New Zealand)

GeoNet reported observing small-scale geyser-like explosions of mud and steam at White Island’s active vent area during the previous three weeks. The ejecta rose as high as 10 m above the active vents on the W part of the crater floor. An increase in frequency of these events was caused by crater lake water that has been rising since early August, covering the active vents. The geysering does not represent increased volcanic activity; the Volcanic Alert Level remained at 1 (the second lowest level on a 0-5 scale) and the Aviation Color Code remained at Green.

Source: GeoNet

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 Copahue
On 30 September OVDAS-SERNAGEOMIN, ONEMI, and SEGEMAR reported that three long-period (LP) earthquakes with notable magnitudes were located about 5.8 km NE of Copahue’s El Agrio Crater. In addition, abundant LP and volcano-tectonic (VT) signals with relatively lower magnitudes were also located in the same area. Some of the events were felt by residents of Caviahue (10 km E) and Copahue 7 km NE) in Argentina. SERNAGEOMIN raised the Alert Level to Orange (second highest level on a four-color scale) and ONEMI updated the Yellow Alert (the middle level on a three-color scale) for residents, noting a restriction for entering a 5-km radius from El Agrio Crater. The seismic network recorded a local M 3.1 VT earthquake at 2340 on 30 September, and a local M 3.7 VT event at 0628 on 1 October. The report also noted that 14 lower-energy events (largest was M 2.4) were recorded.
Sources: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI), Servicio Nacional de Geología y Minería (SERNAGEOMIN), Servicio Geológico Minero Argentino (SEGEMAR)

Report for Poas
OVSICORI-UNA reported that during 16-26 September sulfur dioxide emissions from Poás drifted W and NE, causing a sulfur odor in Alajuela, Heredia, San José, and Cartago. Acidic rain was recorded at the official’s house in the Poás Volcano National Park (PNVP) on 23 September and at Universidad Nacional Costa Rica (UNA) in Heredia on 26 September. At 0540 on 30 September a five-minute-long phreatic eruption ejected sediment, and produced a plume that rose 2 km above the crater rim and drifted SW. Ashfall and a sulfur odor was reported in Trojas de Sarchi and Grecia. Officials closed the PNVP because of the eruption and ongoing elevated seismicity; the park remained closed the next day.
Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA), Tico Times

Report for Ulawun
RVO reported that small, discrete, volcano-tectonic earthquakes at Ulawun began occurring more regularly around 1000 on 30 September; by 1130 they were frequent and by 1220 they were characterized as a swarm. The magnitude of the events overall increased with time and some were felt by residents and accompanied by booming sounds. Events were less frequent and intense during 1730-1930. Sometime afterwards RSAM values erratically increased, reaching a high of 10,000 units between 0130 and 0200 on 1 October. The Alert Level was raised to Stage 2 (the second lowest level on a four-stage scale).

Periods of volcano-tectonic earthquakes slowly transformed into continuous tremor with distinct bursts of high-frequency signals marking discrete volcano-tectonic events during 0430-0500 on 1 October. During this time a new vent opened in a deep valley on the SSW flank at 700 m elevation. The eruption was described as a distinct incandescent glow formed from ejecting material rising less than 100 m above the vent. By dawn light-gray ash plumes were visible rising several hundred meters and drifting NW. Lava fountaining continued throughout the day, and gray ash plumes rose several kilometers above the vent and drifted W. RVO recommended that the Alert Level be raised to Stage 3. On 2 October lava fountains rose several hundred meters and ash-and-steam plumes rose to variable heights between 2 and 5 km, causing ashfall in Navo (W). A lava flow which emerged during the night traveled 1-2 km NW, though visibility was hindered due to weather conditions. Loud rumbling and roaring was noted. Seismicity remained high with RSAM values passing 12,000 units.
Source: Rabaul Volcano Observatory (RVO)

Report for Aira
JMA reported that incandescence from Minamidake crater (at Aira Caldera’s Sakurajima volcano) was occasionally visible at night during 24-30 September. Very small eruptive events were recorded. The Alert Level remained at 3 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)

Report for Asosan
JMA reported that during 25-30 September ash plumes rose as high as 1.6 km above Asosan’s summit crater rim and drifted NE and NW, causing ashfall in areas downwind. The sulfur dioxide emission rate was 2,600 tons per day on 26 September. The Alert Level remained at 2 (on a scale of 1-5).
Source: Japan Meteorological Agency (JMA)

Report for Dukono
Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 25 September-1 October ash plumes from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Ebeko
Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 22-23 September that sent ash plumes up to 3 km (10,000 ft) a.s.l. Ash plumes drifted E and NE, causing ashfall in Severo-Kurilsk. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Report for Etna
INGV reported that intense Strombolian activity from vents at the bottom of Etna’s Voragine Crater (VOR) continued during 23-29 September. Gas emissions from Northeast Crater (NEC) were intense and continuous, and ash plumes were occasionally visible and sometimes accompanied by incandescent flashes. A large ash emission rose from the crater on 27 September and drifted S.
Source: Sezione di Catania - Osservatorio Etneo (INGV)

Report for Ibu
The Darwin VAAC reported that on 28 September ash plumes from Ibu rose to altitudes of 1.8-2.1 km (6,00-7,000 ft) a.s.l. and drifted WNW based on satellite images and weather models. PVMBG reported that at 1806 on 30 September an ash plume rose about 800 m above the crater rim and drifted N. 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 active crater, and 3.5 km away on the N side.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Karangetang
PVMBG reported that during 25 September-1 October lava continued to effuse from Karangetang’s Main Crater (S), traveling as far as 1.5 km down the Nanitu, Pangi, and Sense drainages on the SW and W flanks. Sometimes dense white plumes rose to 300 m above the summit. On 27 and 29 September the Darwin VAAC noted that ash plumes rose to 2.1-2.4 km (7,000-8,000 ft) a.s.l. (about 330-640 m above the crater rim) and drifted SW and W. The Alert Level remained at 2 (on a scale of 1-4).
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Karymsky
KVERT reported that a thermal anomaly over Karymsky was visible in satellite images on 19 September. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Report for Krakatau
PVMBG reported that Anak Krakatau’s seismic network recorded 10 eruptive events during 23-29 September. A webcam at the summit recorded diffuse white plumes rising as high as 150 m from the vent at the bottom of the crater. Eruptive events recorded by the webcam at 0813 on 25 September, 0555 and 0835 on 26 September, and 1520 on 27 September generated dense gray-and-white ash plumes that rose 150-200 m from the vent and generally drifted N. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km-radius hazard zone from the crater.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Manam
The Darwin VAAC reported that on 29 September diffuse ash plumes from Manam rose to altitudes of 2.4-2.7 km (8,000-9,000 ft) a.s.l. and drifted W, based on satellite data and weather models. A sulfur dioxide signature in the plume was also detected. On 30 September RVO reported increased seismicity; the VAAC noted ongoing emissions and a persistent thermal anomaly.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Merapi
PVMBG reported that the lava dome at Merapi slowly grew during 20-26 September and was an estimated 468,000 cubic meters, based on 19 September measurements based on drone photos. Extruded lava fell into the upper parts of the SE flank, generating three block-and-ash flows that traveled as far as 1.5 km down the Gendol drainage. Diffuse white plumes rose as high as 75 m above the summit. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to stay outside of the 3-km exclusion zone.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Nevados de Chillan
ONEMI and SERNAGEOMIN reported that during 24 September-1 October white-to-gray gas plumes from Nevados de Chillán’s Nicanor Crater rose as high as 1.3 km above the rim and drifted NE, E, and SE. Explosions sometimes ejected incandescent material onto the flanks. A lava flow on the NNE flank continued to advance at a low rate. Ashfall was reported 15 km WNW in Las Trancas on 24 September. The Alert Level remained at Orange, the second highest level on a four-color scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-color scale) for the communities of Pinto, Coihueco, and San Fabián, and stated that the public should stay at least 3 km away from the crater on the SW flank and 5 km away on the ENE flank.
Sources: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI), Servicio Nacional de Geología y Minería (SERNAGEOMIN)

Report for Popocatepetl
CENAPRED reported that each day during 25 September-1 October there were 123-224 steam-and-gas emissions from Popocatépetl, some of which contained ash. As many as 10 explosions were recorded each day and crater incandescence was sometimes visible at night. During an overflight on 27 September observatory staff, scientists, and civil protection staff observed a lava dome, 30 m in diameter, at the bottom of the inner crater. The inner crater was 350 m in diameter and 150 m deep based on thermal images and photographs. The Alert Level remained at Yellow, Phase Two (middle level on a three-color scale).
Source: Centro Nacional de Prevencion de Desastres (CENAPRED)

Report for Sabancaya
Instituto Geofísico del Perú (IGP) reported that an average of 15 low-to-medium intensity explosions per day occurred at Sabancaya during 23-29 September. Gas-and-ash plumes rose as high as 1.7 km above the summit and drifted NW, W, and SW. There were 11 thermal anomalies identified in satellite data. 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 Sheveluch
KVERT reported that a thermal anomaly over Sheveluch’s lava dome was identified daily in satellite images during 20-27 September. Explosions recorded during 20-21, 23, and 26 September produced ash plumes that rose to 7 km (23,000 ft) a.s.l. and drifted 580 km ESE. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Report for Shishaldin
On 26 September AVO reported that seismicity at Shishaldin had decreased during the previous few weeks to levels slightly above background. Satellite images indicated decreased surface temperatures at the summit over the same period and showed collapse and slumping of the floor of the summit crater, suggesting a withdrawal of magma. Tiltmeter data suggested that the collapse may have occurred on 19 September. The Aviation Color Code was lowered to Yellow and the Volcano Alert Level was lowered to Advisory.
Source: US Geological Survey Alaska Volcano Observatory (AVO)

Report for Suwanosejima
JMA reported that during 20-27 September white plumes rose 800 m above the rim of Suwanosejima’s Ontake Crater and crater incandescence was visible at night. The Alert Level remained at 2 (on a 5-level scale).
Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Report for Tangkuban Parahu
PVMBG reported that during 23-29 September diffuse white water vapor plumes rose 200 m above the vent on Tangkubanparahu's Ratu Crater floor. The seismic network recorded continuous tremor. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 1.5 km away from the active crater.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Whakaari/White Island
GeoNet reported observing small-scale geyser-like explosions of mud and steam at White Island’s active vent area during the previous three weeks. The ejecta rose as high as 10 m above the active vents on the W part of the crater floor. An increase in frequency of these events was caused by crater lake water that has been rising since early August, covering the active vents. The geysering does not represent increased volcanic activity; the Volcanic Alert Level remained at 1 (the second lowest level on a 0-5 scale) and the Aviation Color Code remained at Green.
Source: GeoNet