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Smithsonian / USGS Weekly Volcanic Activity Report

Weekly Volcanic Activity Map

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

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

Smithsonian / USGS Weekly Volcanic Activity Report for the week of 23 April-29 April 2025
Name Country Volcanic Region Eruption Start Date Report Status
Bezymianny Russia Eastern Kamchatka Volcanic Arc 2024 Dec 24 New
Bulusan Philippines Eastern Philippine Volcanic Arc New
Home Reef Tonga Tofua Volcanic Arc 2024 Dec 4 New
Klyuchevskoy Russia Eastern Kamchatka Volcanic Arc New
Poas Costa Rica Central America Volcanic Arc 2025 Jan 5 New
Ulawun Papua New Guinea Bismarck Volcanic Arc New
Ahyi United States Mariana Volcanic Arc 2024 Aug 5 Continuing
Aira Japan Ryukyu Volcanic Arc 2017 Mar 25 Continuing
Ambae Vanuatu Vanuatu Volcanic Arc Continuing
Ambrym Vanuatu Vanuatu Volcanic Arc Continuing
Atka Volcanic Complex United States Aleutian Ridge Volcanic Arc Continuing
Dukono Indonesia Halmahera Volcanic Arc 1933 Aug 13 Continuing
Etna Italy Sicily Volcanic Province 2022 Nov 27 Continuing
Fuego Guatemala Central America Volcanic Arc 2002 Jan 4 Continuing
Gaua Vanuatu Vanuatu Volcanic Arc Continuing
Great Sitkin United States Aleutian Ridge Volcanic Arc 2021 May 25 Continuing
Ibu Indonesia Halmahera Volcanic Arc 2008 Apr 5 Continuing
Kanlaon Philippines Negros-Sulu Volcanic Arc 2024 Oct 19 Continuing
Lewotobi Indonesia Sunda Volcanic Arc 2023 Dec 23 Continuing
Lewotolok Indonesia Sunda Volcanic Arc 2025 Jan 16 Continuing
Lopevi Vanuatu Vanuatu Volcanic Arc Continuing
Marapi Indonesia Sunda Volcanic Arc 2023 Dec 3 Continuing
Nevado del Ruiz Colombia Northern Andean Volcanic Arc 2014 Nov 18 Continuing
Sangay Ecuador Northern Andean Volcanic Arc 2019 Mar 26 Continuing
Semeru Indonesia Sunda Volcanic Arc 2017 Jun 6 Continuing
Sheveluch Russia Eastern Kamchatka Volcanic Arc 1999 Aug 15 Continuing
Yasur Vanuatu Vanuatu Volcanic Arc 1270 ± 110 years Continuing
All times are local unless otherwise stated.
Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 21,253 individual reports over 1,269 weeks (average of 17 per week) on 339 different volcanoes.

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


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A Google Earth network link for the Weekly Volcanic Activity Report can be loaded into the free Google Earth software, and in turn will load placemarks for volcanoes in the current weekly report. Placemark balloons include the volcano name, report date, report text, sources, and links back to the GVP volcano profile page and to the complete Weekly Report for that week. This feature was first made available on 1 April 2009.

 Criteria & Disclaimers

Criteria



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

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

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

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

Disclaimers



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

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

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

4. Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.

5. USGS Disclaimer Statement for this Website:

Information presented on this website is considered public information and may be distributed or copied. Use of appropriate byline/photo/image credit is requested. We strongly recommend that USGS data be acquired directly from a USGS server and not through other sources that may change the data in some way. While USGS makes every effort to provide accurate and complete information, various data such as names, telephone numbers, etc. may change prior to updating. USGS welcomes suggestions on how to improve our home page and correct errors. USGS provides no warranty, expressed or implied, as to the accuracy, reliability or completeness of furnished data.

Some of the documents on this server may contain live references (or pointers) to information created and maintained by other organizations. Please note that USGS does not control and cannot guarantee the relevance, timeliness, or accuracy of these outside materials.

For site security purposes and to ensure that this service remains available to all users, this government computer system employs software programs to monitor network traffic to identify unauthorized attempts to upload or change information, or otherwise cause damage. Unauthorized attempts to upload information or change information on this website are strictly prohibited and may be punishable under the Computer Fraud and Abuse Act of 1986 and the National Information Infrastructure Protection Act. Information may also be used for authorized law enforcement investigations. (Last modified September 21, 1999.)

U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA
URL: https://volcano.si.edu/reports_weekly.cfm

 Acronyms and Abbreviations

a.s.l. - above sea level

AVO - Alaska Volcano Observatory

AVHRR - Advanced Very High Resolution Radiometer

CENAPRED - Centro Nacionale de Prevencion de Desastres (México)

CONRED - Coordinadora Nacional para la Reducción de Desastres

COSPEC - Correlation Spectrometer

CVGHM (formerly VSI) - Center of Volcanology and Geological Hazard Mitigation

CVO - Cascades Volcano Observatory (USGS)

GMS - Geostationary Meteorological Satellite

GOES - Geostationary Operational Environmental Satellite

GVO - Goma Volcano Observatory

GVP - Global Volcanism Program (Smithsonian Institution)

HVO - Hawaiian Volcano Observatory (USGS)

ICE - Instituto Costarricense de Electricidad (Costa Rica)

IG - Instituto Geofísico (Ecuador)

IGNS - Institute of Geological and Nuclear Sciences (New Zealand) - now GNS Science

INETER - Instituto Nicaragüense de Estudios Territoriales (Nicaragua)

INGEMMET - Instituto Geológical Minero y Metalúrgico (Peru)

INGEOMINAS - Instituto Colombiano de Geología y Minería (Colombia)

INGV-CT - Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Catania (Italy)

INSIVUMEH - Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hidrologia (Guatemala)

IRD - Institut de Recherche pour le Développement (France)

JMA - Japanese Meteorological Agency

KEMSD - Kamchatkan Experimental and Methodical Seismilogical Department

KVERT - Kamchatkan Volcanic Eruption Response Team

M - magnitude

METEOSAT - Meteorological Satellite

MEVO - Mount Erebus Volcano Observatory

MODIS - Moderate Resolution Imaging Spectroradiometer

MVO - Montserrat Volcano Observatory

MWO - Meteorological Watch Office

NEIC - National Earthquake Information Center

NIED - National Research Institute for Earth Science and Disaster Prevention (Japan)

NOAA - National Oceanic and Atmospheric Administration

NOTAM - Notice to Airmen

OVDAS - Observatorio Volcanologico de los Andes del Sur (Chile)

OFDA - Office of US Foreign Disaster Assistance

ONEMI - Oficina Nacional de Emergencia - Ministerio del Interior (Chile)

OVPDLF - Observatoire Volcanologique du Piton de la Fournaise (France)

OVSICORI-UNA - Observatorio Vulcanologico y Sismologico de Costa Rica, Universidad Nacional (Costa Rica)

PHIVOLCS - Philippine Institute of Volcanology and Seismology (Philippines)

RSAM - Real-time Seismic Amplitude Measurement

RVO - Rabaul Volcano Observatory

SERNAGEOMIN - Servicio Nacional de Geologia y Mineria (Chile)

SIGMET - Significant Meteorological Information

SNET - Servicio Nacional de Estudios Territoriales (El Salvador)

SVERT - Sakhalin Volcanic Eruption Response Team (Russia)

USAID - US Agency for International Development

USGS - United States Geological Survey

UTC - Coordinated Universal Time

VAAC - Volcanic Ash Advisory Center

VAFTAD - Volcanic Ash Forecast Transport And Dispersion

VDAP - Volcano Disaster Assistance Program (USGS)

VHP - Volcano Hazards Program (USGS)

VRC - Volcano Research Center (Japan)

Report for Bezymianny
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported increased activity at Bezymianny and tall ash plumes on 23 April. A large thermal anomaly was visible in satellite images for several days during 17-24 April. Incandescent avalanches continued to descend the flanks. Ash clouds from the avalanches rose 4 km (13,100 ft) a.s.l. and drifted 36 km W on 20 April, rose 2.5-3 km (8,200-9,800 ft) a.s.l. and drifted 45 km WSW on 21 April, and rose up to 4 km and drifted 35 km W on 22 April.

At about 0145 on 23 April eruptive activity produced a dense ash plume that rose to 9 km (29,500 ft) a.s.l. An ash cloud, 10 x 10 km in dimension, was visible in satellite images drifting NNW. At 0351 the Aviation Color Code was raised to Red (the highest level on a four-color scale). Hot avalanches continued to descend the flanks and gas-and-steam emissions were visible. Ash was not visible in subsequent images; at 0600 on 23 April the Aviation Color Code was lowered to Orange. A stronger explosive eruption began later that day at 2310 and produced an ash plume that rose 11 km (36,100 ft) a.s.l. Satellite images showed a 36 x 26 km ash cloud drifting NNE. At 2348 the Aviation Color Code was raised to Red. The period of increased activity ended at around 0300 on 24 April. Ashfall was reported in the villages of Atlasovo, Lazo, and Milkovo. According to Kamchatka Volcanological Station (Volkstat) pyroclastic flows descended the flanks. KVERT noted that at 0510 a satellite images showed an ash cloud at altitudes of 7-7.5 km (23,000-24,600 ft) a.s.l. that was covered 110 x 175 km and had reached about 320 km SW of the volcano. At 0600 the Aviation Color Code was lowered to Orange. Dates are reported in UTC; specific events are in local time where noted.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Kamchatka Volcanological Station
Report for Bulusan
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported increased activity at Bulusan on 27 April and a phreatic eruption on 28 April. Seismicity had increased on 12 April and continued to be elevated, prompting a special report to be issued on 21 April. On 27 April there were 53 volcanic earthquakes detected by the seismic network. Detection of strong tremor and infrasound signals started at 0354 on 28 April and lasted about 29 minutes. Local government officials reported rumbling sounds towards the end of that period in the barangays of Cogon, Bacolod, and Patag (Irosin) and in Añog and Rangas (Juban). Monitoring data indicated a phreatic eruption started about 15 minutes later, which continued during 0436-0500. A voluminous ash-and-gas plume rose 4.5 km above the crater rim and drifted generally W and SW. A small-volume pyroclastic density current descended the SW flank as far as 3 km and produced an ash cloud based on a Disaster Response Operations Monitoring and Information Center (DROMIC) report. Ashfall up to 1 mm thick was reported in Cogon, Tinampo, Omagom, Gulang-Gulang, and Bolos (Irosin), in Puting Sapa, Buraburan, and Guruyan (Juban), and in Tula-tula Sur, Caditaan, Cadandanan, Siuton, Salvacion, and Busay (Magallanes). A sulfur odor was reported in Cogon. A total of 86 volcanic earthquakes were recorded through 2000 and continuous gas emissions at the summit continued at least through 2030. The Alert Level was raised to 1 (the second lowest level on a scale of 0-5). The public was reminded not to enter the 4-km-radius Permanent Danger Zone (PDZ) and to be vigilant within the 2-km Extended Danger Zone (EDZ) on the SE flank.

A second phreatic eruption began at 1943 on 29 April and lasted about 77 minutes based on seismic and infrasound data. Weather clouds obscured views of the ash-and-gas cloud, though it likely drifted SW based on the locations of 19 communities affected by ashfall. Ashfall from trace amounts to depths around 1 cm was reported in Cogon, Tinampo, Monbon, Bolos, Gulang-Gulang, Gabao, Bulawan, and Macawayan (Irosin), in Zone 7, Somagongsong, Beguin, Aquino, San Francisco, Calomagon, Inararan, Cadandanan, Dolos, and Polot (Bulan), and in Guruyan (Juban). Rumbling was heard in Cogon and Bagsangan (Irosin). According to the Office of Civil Defense, at around 2100 there were 59 families in Cogon that evacuated to two shelters. Supplies, including hygiene kits and N95 masks, were delivered to residents and local governments were receiving support to clean up the ashfall. PHIVOLCS noted that by 2000 the seismic network had recorded a total of 54 volcanic earthquakes that day. Prior to the eruption, sulfur dioxide emissions averaged 548 tonnes per day (t/d), higher than the baseline of less than 200 t/d. The DROMIC report issued at 1800 on 30 April stated that 211 people (65 families) were in two shelters. Additionally, two people were staying with relatives or friends.
Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Office of Civil Defense, Disaster Response Operations Monitoring and Information Center (DROMIC)
Report for Home Reef
The Tonga Geological Services reported continuing activity at Home Reef. Satellite imagery from 4 April captured a series of small low-level ash plumes generated by explosions. Surface changes at the vent, including new tephra deposits and lava textures, were identified in a 5 April satellite image. A satellite image from 11 April indicated that the vent had the same dimensions as previously reported, 125 m N-S and 110 m W-E. The dome in the vent had grown, mainly to the SW, and spalled or ejected material that rolled down to the shoreline. In both 11 and 26 April images steam plumes rose from the vent and water around the island was discolored. Moderate thermal anomalies were detected by the Middle InfraRed Observation of Volcanic Activity (MIROVA) system during 8-28 April. A sulfur dioxide emission was identified in a 22 April satellite image. Ash emissions were visible in satellite data at around 1400 on 26 April, prompting Tonga Geological Services to raise the Aviation Color Code to Orange (the second highest level on a four-level scale) that same day. According to the Wellington VAAC intermittent, low-level ash plumes were visible in satellite images during 26-27 and 29 April rising 0.9-1.2 km (3,000-4,000 ft) a.s.l. and drifting W and NW. The Maritime Alert Level remained at Orange (the third level on a four-level scale), and mariners were advised to stay at least 2 nautical miles (3.7 km) away from the island. The Alert Level for residents of Vava’u and Ha’apai remained at Green (the first level on a four-level scale).
Sources: Tonga Geological Services, Government of Tonga, Wellington Volcanic Ash Advisory Center (VAAC)
Report for Klyuchevskoy
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that a thermal anomaly at Klyuchevskoy was identified in satellite images during 18-22 April. A new Strombolian eruption began on 20 April. Weather clouds obscured views during 23-25 April. The Aviation Color Code remained at Yellow (the second lowest 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 Poas
The Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported frequent explosions and ash-and-gas plumes at Poás during 23-29 April. Seismicity, specifically background tremor, had decreased on 17 April and remained at stable levels with increases related to eruptive events during 21-23 April. The number of long-period events increased, and occasional periods of harmonic tremor began to be recorded on 21 April. Analysis of ash showed an increased proportion of juvenile material. Inflation continued to be detected.

Eruptive events at 0529 and at 0744 on 23 April generated ash-and-gas plumes that rose at least 3 km and 1 km above the crater rim, respectively. Each event lasted about five minutes. The plumes drifted SW and NE, causing ashfall in areas downwind including Belén, Alajuela (20 km S), Palmares (27 km SW), San Rafael, and San Pedro de Poás (14 km S). During 23-24 April significant and almost continuous gas-and-steam plumes with some ash rose from the crater and drifted mainly SW. Incandescence at the vents was visible at night. A small, one-minute-long eruptive event at 0107 on 24 April produced a plume that rose 1 km above the crater rim and drifted NE. Ballistics around 250 degrees Celsius were ejected to the E. A larger event was recorded at around 2030. A period of moderate-to-intense activity began at 2312 on 25 April and intensified at 2322; an ash-and-gas plume rose 1 km above the crater rim and drifted W. Incandescent material, about 300 degrees Celsius, was ejected from the vents onto the crater floor and cooled quickly. Activity was again intense during 0230-0420 on 26 April based on seismic data. During 0500-0600 hot blocks were observed being ejected from Boca C. Ash-and-gas plumes rose a few hundred meters to 1 km above the crater rim and drifted in variable directions. Almost continuous gas-and-steam emissions from both Boca A and Boca C during 27-28 April rose as high as 1 km above the crater rim. The emissions were punctuated by pulses of ash that rose 500 m and drifted in variable directions on 27 April and small eruptive pulses on 28 April that ejected incandescent material from the vents. Sulfur dioxide emissions were 2,000-10,000 tons per day. Overnight during 28-29 April almost continuous emissions rose 300 m from both vents and drifted SW; the emissions contained a smaller amount of ash than during recent days. The volcano’s Alert Level remained at 3 (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest color on a four-color scale).
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
Report for Ulawun
The Rabaul Volcano Observatory (RVO) reported that activity at Ulawun was low during 7-25 April. Summit emissions were white and had variable densities. On some days there were no emissions. Brief low rumbling sounds were heard during 15-16 and 19 April. In general seismicity was low, though slightly higher that background (RSAM values of 100-200). Data from the seismic station (UULA), 2.8 km from the summit on the lower WSW flank, was characterized by both low- and high-frequency volcanic earthquakes, with low-frequency earthquakes being the dominant signal. Brief surges in seismicity activity occasionally occurred and consisted of changes from discrete low- and high-frequency earthquakes to low-level, continuous volcanic tremors that lasted between several minutes and less than few hours. The Alert Level was at Stage 1 (the lowest level of a four-stage scale).
Source: Rabaul Volcano Observatory (RVO)
Report for Ahyi
Unrest at Ahyi Seamount may have continued during 18-25 April. Signals coming from the direction of Ahyi were identified in data from underwater pressure sensors near Wake Island (about 2,270 km E of Ahyi) on 18 and 20 April. No signs of activity at the ocean’s surface were identified in satellite images. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale).
Source: US Geological Survey
Report for Aira
The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 21-28 April. Nightly crater incandescence was visible at Minamidake Crater in webcam images, and very small eruptive events were recorded during 25-28 April. An eruptive event at 1803 on 21 April generated an ash plume that rose 1.6 km above the crater rim. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 2 km away from both the Minimadake and Showa craters.
Source: Japan Meteorological Agency (JMA)
Report for Ambae
On 24 April the Vanuatu Meteorology and Geohazards Department (VMGD) reported that steam and/or gas emissions from the active vents at Ambae were visible in webcam images during 1-4, 7, 11, and 19 April. Sulfur dioxide emissions were detected in satellite data during 1-8, 10, and 21 April. Seismic data also confirmed ongoing unrest. The Alert Level remained at 2 (on a scale of 0-5), and the public was warned to stay outside of the Danger Zone, defined as a 2-km radius around the active vents in Lake Voui, and away from drainages during heavy rains.
Source: Vanuatu Meteorology and Geohazards Department (VMGD)
Report for Ambrym
On 24 April the Vanuatu Meteorology and Geohazards Department (VMGD) reported ongoing fumarolic activity at Ambrym from both Benbow and Marum craters based on webcam images. Seismic data confirmed ongoing unrest. A low-level thermal anomaly was identified in satellite data on 9 April indicative of increased surface temperatures. The Alert Level remained at 2 (on a scale of 0-5). VMGD warned the public to stay outside of Permanent Danger Zone A, defined as a 1-km radius around Benbow Crater and a 2-km radius around Marum Crater, and to stay 500 m away from the ground cracks created by the December 2018 eruption.
Source: Vanuatu Meteorology and Geohazards Department (VMGD)
Report for Atka Volcanic Complex
A small, short-lived explosion from the summit of Korovin, one of the volcanoes at the Atka volcanic complex, was detected at 1034 on 25 April, prompting the Alaska Volcano Observatory (AVO) to raise the Volcano Alert Level to Advisory (the second lowest level on a four-level scale) and the Aviation Color Code to Yellow (the second lowest color on a four-color scale). High weather clouds obscured views at the time of the explosion, preventing confirmation of the event in satellite observations. Similar past events at the Atka complex did not result in ash emissions of noticeable ashfall. No further activity was detected during 26-29 April; seismicity was low and weather clouds obscured webcam and satellite views.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Dukono
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Dukono continued during 23-29 April. White-and-gray ash plumes rose 600-1,100 m above the crater rim and drifted E on most days; no plumes were visible on 24 April. The Alert Level remained at Level 2 (on a scale of 1-4) and the public was warned to stay 4 km away from the Malupang Warirang Crater.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Etna
The Sezione di Catania - Osservatorio Etneo (INGV) reported continuing activity at Etna during 21-27 April, characterized by Strombolian activity with lava overflows at SE Crater and gas emissions at Bocca Nuova Crater, NE Crater, and Voragine. Strombolian activity at SE Crater began at 2000 on 22 April that involved at least three vents and was followed by lava overflowing onto the SE flank. At 2145 a second lava flow descended the S flank. The activity ceased at around 0300 on 23 April. Satellite data from 27 April was used to map the flows. The SE-flank flow covered an area of about 34,000 square meters and was about 700 m long, reaching 2,940 m elevation. The S-flank flow covered about 6,000 square meters and was about 200 m long, reaching 3,170 m elevation.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Fuego
The Instituto Nacional de Sismología, Vulcanología, Meteorología e Hidrología (INSIVUMEH) reported a few explosions and the ejection of incandescent material at Fuego during 22-29 April. White steam-and-gas plumes rose as high as 100 m above the summit during the week. At night a few incandescent blocks occasionally collapsed and formed minor avalanches. During 23-24 April there were 1-3 weak explosions reported. Additional weak explosions during 27-28 April took place 6-8 times per hour, producing faint rumbling sounds and ash plumes that rose just over 800 m above the summit and drifted up to 15 km SW. Incandescent material was observed at night being ejected 100-200 m above the summit. Avalanches of material descended the flanks, reaching vegetated areas. Four weak explosions accompanied by weak rumbling was recorded during 28-29 April.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Gaua
On 24 April the Vanuatu Meteorology and Geohazards (VMGD) reported that unrest continued at Gaua. Sulfur dioxide emissions were identified in satellite images during 2-3 and 6-8 April, and steam and/or gas emissions from the vent were visible in images on 17 April. A low-level thermal anomaly was identified in satellite images on 4, 11, and 19 April, indicative of increased surface temperatures. The Alert Level remained at 2 (on a scale of 0-5) and the public was warned to stay away from the main cone.
Source: Vanuatu Meteorology and Geohazards Department (VMGD)
Report for Great Sitkin
The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick flow in Great Sitkin’s summit crater during 23-29 April. Small daily earthquakes were detected by the seismic network. Weather clouds often obscured satellite and webcam views of the volcano. 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 Ibu
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Ibu continued during 23-29 April. Dense gray ash plumes rose 400-700 m above the summit and drifted E and NE on most days. Eruptive events were recorded by the seismicity network on 24 and 26 April, though weather conditions prevented visual observations. Nighttime crater incandescence was visible in some webcam images. The Alert Level remained at 3 (the second highest level on a four-level scale) and the public was advised to stay 4 km away from the active crater and 5 km away from the N crater wall opening.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Kanlaon
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 22-28 April. The seismic network recorded 7-36 daily volcanic earthquakes and one period of volcanic tremor (10 minutes long) on 28 April. Daily sulfur dioxide emissions ranged from 1,693 to 2,736 tonnes per day. Gas-and-steam emissions generally rose 150-400 m above the crater rim and drifted WNW, W, and SW. There was one ash emission on 28 April that lasted 10 minutes long based on the seismic signal. The ash-and-gas plume rose 200 m and drifted SW. The Alert Level remained at 3 (on a scale of 0-5); the public was warned to stay 6 km away from the summit and pilots were warned not to fly close to the volcano.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
Report for Lewotobi
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Lewotobi Laki-laki continued during 23-29 April. Gray or gray-to-black ash plumes rose 500 m above the summit, to as high as 4 km above the summit, and drifted multiple directions during 24-28 April. Though the view was often obscured due to weather or volcanic plumes, incandescence around the upper flanks was visible in a webcam image at 0215 on 25 April. At 2115 on 27 April an eruptive event generated a dense gray as plume that rose 4 km above the summit and drifted N and NE. A corresponding webcam images showed trails of incandescent material on the upper flanks. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 6 km away from the center of Laki-laki.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Lewotolok
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that an eruption at Lewotolok was ongoing during 23-29 April. White steam-and-gas plumes rose as high as 100 m above the summit of the cone and drifted E and SE. Nighttime webcam images showed incandescent material being ejected above the summit. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 2 km away from the vent and 2.5 km away on the S, SE, and W flanks.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Lopevi
On 24 April the Vanuatu Meteorology and Geohazards Department (VMGD) reported that during the previous month seismic data confirmed continuing unrest at Lopevi. Small fumarolic steam plumes were continuously emitted at the summit crater based on webcam images from 1, 19, and 20 April. Low-level thermal anomalies were identified in satellite images on 6 and 20 April, indicative of increased surface temperatures. The Alert Level remained at 2 (on a scale of 0-4).
Source: Vanuatu Meteorology and Geohazards Department (VMGD)
Report for Marapi
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity from Verbeek Crater at Marapi (on Sumatra) continued during 23-29 April. Dense gray ash plumes rose 350-1,000 m above the summit and drifted N during 25 and 27-28 April. Two more eruptive events were recorded on 28 April but not visually observed due to weather conditions. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 3 km away from the active crater.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Nevado del Ruiz
The Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that eruptive activity at Nevado del Ruiz continued during 22-28 April. Seismic data indicated that events associated with fluid movement increased in both number and intensity compared to the previous week. Some of the seismic events were associated with pulsating ash emissions; webcam images confirmed these ash emissions, including some with higher-temperature ejecta. Gas-and-steam plumes rose as high as 1.8 km above the summit and drifted NNE, N, and NNW; the highest plume, a gas-and-ash emission that rose as high as 2 km above the summit, occurred at 2251 on 26 April. Seismicity associated with rock fracturing stayed at similar levels compared to the previous week. The earthquakes were mainly located below Arenas Crater and the NE, E, S, and SW flanks within 5 km at depths of 1-8 km. Low-energy thermal anomalies on the crater floor were identified in satellite data, though weather clouds often obscured views. Sulfur dioxide emissions detected in satellite data continued to be significant. The Alert Level remained at Yellow (the second level on a four-level scale), and the public was warned to stay out of the restricted areas around Arenas Crater, not to spend long periods of time on the Murillo-Cerro Gualí Road, and to avoid drainages in the high-threat zones.
Source: Servicio Geológico Colombiano (SGC)
Report for Sangay
The Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN) reported high levels of eruptive activity at Sangay during 21-29 April. The seismic network recorded 124-258 daily explosions. Several ash-and-gas plumes were observed rising more than 4 km above the summit during 22-24 April, as high as 3 km above the summit during 24-25 April, and up to 1.7 km above the summit during the rest of the week; weather clouds sometimes obscured views during the last half of the week and almost completely obscured views during 21-22 and 26-27 April. The ash-and-gas plumes drifted mainly NW, W, and SW. Minor ashfall was reported in the province of Chimborazo during 22-25 April, and especially in the parish of Cebadas and in Utucun, Rayoloma, and Pueblo Cebadeño during 23-24 April. Nighttime crater incandescence was visible. On most nights several incandescent avalanches were observed descending the SE flank as far as 1 km below the summit. Incandescent material was ejected 100 m above the summit during 23-24 April. Secretaría de Gestión de Riesgos (SGR) 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 Semeru
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Semeru during 23-29 April, with multiple daily eruptive events recorded by the seismic network. White-and-gray ash plumes rose 300-900 m above the summit and drifted in multiple directions. Incandescence at the summit was visible in 24 and 26 April webcam images. The Alert Level remained at 2 (the second lowest level 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
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that lava extrusion may have continued at Sheveluch’s “300 years of RAS” dome on the SW flank of Old Sheveluch and at the Young Sheveluch dome during 17-24 April. Thermal anomalies over the domes were identified in satellite images during 20-21 April; weather clouds obscured views on the other days. The Aviation Color Code remained at Orange (the second highest 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 Yasur
On 24 April the Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur continued at a level of “major unrest,” as defined by the Alert Level 2 status (on a scale of 0-5). Satellite and webcam images indicated that explosions continued, producing emissions of gas, steam, and/or ash. Sulfur dioxide gas emissions were identified in satellite images during 1-8, 11-12, 15, 17-19, and 21-22 April, and low-level thermal anomalies were identified during 1, 3, 5, 7, 12, 16, 18-19, and 21 April. Seismic data confirmed continuing volcanic activity with explosions that were occasionally strong. The report warned that ejected material from explosions could fall in and around the crater. The public was reminded to not enter the restricted area within 600 m around the boundaries of the Permanent Exclusion Zone, defined by Danger Zone A on the hazard map.
Source: Vanuatu Meteorology and Geohazards Department (VMGD)