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 20 April-26 April 2022
Name	Location	Eruption Start Date	Report Status
Edgecumbe	Southeastern Alaska (USA)	—	New
Karymsky	Eastern Kamchatka (Russia)	—	New
Krakatau	Sunda Strait	—	New
Purace	Colombia	—	New
Ruapehu	North Island (New Zealand)	—	New
Aira	Kyushu (Japan)	2017 Mar 25	Continuing
Davidof	Aleutian Islands (USA)	—	Continuing
Dukono	Halmahera	1933 Aug 13	Continuing
Fuego	South-Central Guatemala	2002 Jan 4	Continuing
Great Sitkin	Andreanof Islands (USA)	2021 May 25	Continuing
Ibu	Halmahera	2008 Apr 5	Continuing
Kilauea	Hawaiian Islands (USA)	—	Continuing
Langila	New Britain (Papua New Guinea)	2015 Oct 22 (?)	Continuing
Lewotolok	Lembata Island	2020 Nov 27	Continuing
Merapi	Central Java	2020 Dec 31	Continuing
Pavlof	Alaska Peninsula, Alaska	—	Continuing
Popocatepetl	Mexico	2005 Jan 9	Continuing
Rincon de la Vieja	Costa Rica	2021 Jun 28	Continuing
Sabancaya	Peru	2016 Nov 6	Continuing
Santa Maria	Southwestern Guatemala	1922 Jun 22	Continuing
Semeru	Eastern Java	2017 Jun 6	Continuing
Semisopochnoi	Aleutian Islands (USA)	—	Continuing
Sheveluch	Central Kamchatka (Russia)	1999 Aug 15	Continuing
Suwanosejima	Ryukyu Islands (Japan)	2004 Oct 23	Continuing
Wolf	Isla Isabela (Galapagos)	—	Continuing

All times are local unless otherwise stated.

Edgecumbe | 20 April-26 April 2022 | New Activity / Unrest Cite this Report

Edgecumbe
Southeastern Alaska (USA)

AVO stated that a seismic swarm beneath Kruzof Island near Edgecumbe that began at about 0200 on 11 April had declined to background levels by 22 April. The swarm prompted an in-depth analysis of satellite data which spanned the last 7.5 years. The data showed that a broad area of uplift, about 17 km in diameter, was located about 2.5 km E of Edgecumbe. The uplift began in August 2018 and deformed at a rate of up to 8.7 cm per year in the center of the area, totaling 27 cm of uplift; the deformation was ongoing. Retrospective analysis of seismic data revealed that earthquakes started occurring in 2020, though the recent swarm was unusual. The deformation and seismic data together suggested magma movement beneath the volcano, consistent with an intrusion at about 5 km below sea level. The closest seismic station to the volcano was on Sitka, 24 km E; both the Volcano Alert Level and Aviation Color Code remained at Unassigned due to the lack of dedicated, local instrumentation.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Karymsky | 20 April-26 April 2022 | New Activity / Unrest Cite this Report

Karymsky
Eastern Kamchatka (Russia)

KVERT reported that a thermal anomaly over Karymsky was visible in satellite images during 15-22 April. Explosions during 17-19 and 21 April generated ash plumes that rose as high as 7.5 km (24,600 ft) a.s.l. and drifted 500 km NE. SE, and E. A powerful explosion at 0805 on 20 April (local time) generated ash plumes that rose as high as 11 km (36,100 ft) a.s.l. and drifted more than 2,000 km NE. KVERT raised the Aviation Color Code to Red (the highest level on a four-color scale). Ashfall was reported in the territory of the Kronotsky Reserve (Semyachinsky, Valley of Geysers), 50 km NE, and at Cape Nalychevo, 100 km S. Explosions continued through the day; ash plumes rising to 5 km (16,400 ft) a.s.l. were visible in satellite images at 1500, local time. The previous ash plume was about 505 x 130 km and drifted NE, S, and SE at an altitude of 8.7 km (28,500 ft) a.s.l. The Aviation Color Code was lowered to Orange by 1544, local time, on 20 April.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Krakatau | 20 April-26 April 2022 | New Activity / Unrest Cite this Report

Krakatau
Sunda Strait

PVMBG reported that the eruption at Anak Krakatau had intensified. Dense white, gray, and black ash plumes rose as high as 1 km above the summit and drifted SW during 17-19 April. Strombolian activity was first observed on 17 April; that same day that sulfur dioxide emissions increased to 181.1 tons per days from 28.4-68.4 tons per day recorded during 14-15 April. A dense gray-black ash plume rose around 800 m above the summit at 0621 on 21 April and drifted E. At 0049, 0145, 0237, and 1730 on 22 April dense gray-to-black ash plumes rose 500-1,500 m above the summit and drifted SW. Incandescent material was occasionally ejected above the vent. Sulfur dioxide emissions notably increased to 9,219 tons per day on 23 April. That same day, at around 1219, lava flowed into the sea and produced a white steam plume at the entry point. Ash plumes were taller on 23 April, rising to 3 km above the summit at 0608, 1200, and 2020, with SSW, S, and SE drifts. The plumes continued to be characterized as dense, and white, gray, and black in color. On 24 April PVMBG raised the Alert Level to 3 (on a scale of 1-4), and the public was warned to stay at least 5 km away from the crater.

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

Purace | 20 April-26 April 2022 | New Activity / Unrest Cite this Report

Purace
Colombia

Observatorio Vulcanológico y Sismológico de Popayán, Servicio Geologico Colombiano (SGC), reported that during 19-25 April the number and magnitudes of earthquakes at Puracé was similar to the previous week. Signals included 72 volcano-tectonic (VT) events, indicating rock fracturing, along with 207 long-period (LP) events and 14 low-energy tremor pulses, indicating fluid movement. Data from the GNSS (Global Navigation Satellite System) geodetic network continued to show inflation on the centimeter scale. Sulfur dioxide emissions were lower than the previous week, with values of 937-992 tonnes per day, and gas plumes drifted NW. During a field visit on 22 April scientists observed no changes to the crack near Puracé and Curiquinga volcanoes, and no visible gas emissions. Additional cracks, oriented NW-SE, were observed, in addition to volcanic ash deposits that were likely emplaced on 29 March. The Alert Level remained at Yellow (the second lowest on a four-color scale).

Source: Servicio Geológico Colombiano (SGC)

Ruapehu | 20 April-26 April 2022 | New Activity / Unrest Cite this Report

Ruapehu
North Island (New Zealand)

On 26 April GeoNet reported that elevated unrest at Ruapehu had been ongoing for the past five weeks, characterized by lake water heating, volcanic gas output, and strong volcanic tremor. Tremor levels fluctuated the past week but represented a record for the longest and strongest tremor episode ever recorded at the volcano. The lake water temperature remained at 37 degrees Celsius, indicating a substantial amount of heat from magma at a shallow depth (0.5-2 km), though water chemistry showed no change based on sampling during 31 March-15 April. The Volcanic Alert Level remained at 2 (on a scale from 0-5) and the Aviation Color Code remained at Yellow.

Source: GeoNet

Aira | 20 April-26 April 2022 | Continuing ActivityCite this Report

Aira
Kyushu (Japan)

JMA reported that very small eruptive events at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) were recorded during 18-25 April. Crater incandescence was periodically visible at night. The sulfur dioxide emissions were slightly high at 1,300 tons per day on 19 April but then dropped to 500 tons per day on 22 April. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.

Source: Japan Meteorological Agency (JMA)

Davidof | 20 April-26 April 2022 | Continuing ActivityCite this Report

Davidof
Aleutian Islands (USA)

AVO lowered both the Aviation Color Code and the Volcano Alert Level for Davidof to Unassigned on 21 April, noting that the earthquake swarm which began in January had declined in the previous few weeks. It is unknown if the swarm was due to tectonic processes or volcanic unrest. The level “Unassigned” means that there is not sufficient instrumentation on the volcano for AVO to characterize a base level of activity; the closest seismometer was on Little Sitkin (15 km E).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Dukono | 20 April-26 April 2022 | Continuing ActivityCite this Report

Dukono
Halmahera

Based on satellite and wind model data, the Darwin VAAC reported that during 21-23 and 25 April ash plumes from Dukono rose to 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: Darwin Volcanic Ash Advisory Centre (VAAC), Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Fuego | 20 April-26 April 2022 | Continuing ActivityCite this Report

Fuego
South-Central Guatemala

INSIVUMEH reported that 2-10 explosions per hour were recorded at Fuego during 21-25 April, generating ash plumes that rose as high as 1.3 km above the crater rim. The ash plumes mainly drifted as far as 15 km SE, S, and SW causing daily ashfall in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Sangre de Cristo (8 km WSW), Finca Palo Verde, Finca la Asunción, El Zapote (10 km S), San Pedro Yepocapa (8 km NW), Ceylon, San Andrés Osuna, and La Rochela. Shock waves rattled structures in communities around the volcano on most days and occasional rumbling was heard. Block avalanches descended the flanks in all directions, but most commonly were visible in the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Honda, and Las Lajas (SE) drainages, often reaching vegetated areas. Explosions ejected incandescent material 100-350 m above the summit during 21-24 April.

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

Great Sitkin | 20 April-26 April 2022 | Continuing ActivityCite this Report

Great Sitkin
Andreanof Islands (USA)

AVO reported that slow lava effusion at Great Sitkin continued during 20-26 April, and very low seismicity persisted. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Ibu | 20 April-26 April 2022 | Continuing ActivityCite this Report

Ibu
Halmahera

PVMBG reported that the eruption at Ibu continued during 22-26 April. Daily dense gray ash plumes generally rose 400-1,500 m above the summit and drifted W and NE, though at 0948 on 25 April ash plumes rose up to 3 km above the summit and drifted W. The Alert Level remained at a 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: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Kilauea | 20 April-26 April 2022 | Continuing ActivityCite this Report

Kilauea
Hawaiian Islands (USA)

HVO reported that lava continued to effuse from a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 19-26 April, entering an active lava lake and flowing onto the crater floor. The surface of the lava lake was active all week, and the height of the lake fluctuated; the lake occasionally overflowed the rim, sending lava onto the crater floor. Daily breakouts occurred along the N, NE, E, and S parts of the crater. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Langila | 20 April-26 April 2022 | Continuing ActivityCite this Report

Langila
New Britain (Papua New Guinea)

The Darwin VAAC reported that on 24 April an ash plume from Langila rose 2.1 km (7,000 ft) a.s.l. and drifted SW. The plume had dissipated within 5.5 hours.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Lewotolok | 20 April-26 April 2022 | Continuing ActivityCite this Report

Lewotolok
Lembata Island

PVMBG reported that the eruption at Lewotolok continued during 19-26 April. Daily white-and-gray ash plumes rose 50-400 m above the summit and drifted W, NW, and E. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit crater and 4 km away from the crater on the SE flank.

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

Merapi | 20 April-26 April 2022 | Continuing ActivityCite this Report

Merapi
Central Java

BPPTKG reported that the eruption at Merapi continued during 15-21 April. The heights and morphologies of the SW lava dome and the central lava dome were unchanged from the previous week, and seismicity remained at high levels. As many as 150 lava avalanches traveled a maximum of 2 km mostly down the Bebeng drainage on the SW flank. One pyroclastic flows traveled 2 km SW down the Bebeng. 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)

Pavlof | 20 April-26 April 2022 | Continuing ActivityCite this Report

Pavlof
Alaska Peninsula, Alaska

AVO reported that the eruption at a vent on Pavlof’s upper E flank was ongoing during 20-26 April, though weather conditions sometimes prevented visual observations. Seismic tremor persisted and daily elevated surface temperatures were identified in satellite images. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Popocatepetl | 20 April-26 April 2022 | Continuing ActivityCite this Report

Popocatepetl
Mexico

CENAPRED reported that the eruption at Popocatépetl continued during 19-26 April. Each day there were 6-27 steam-and-gas emissions that rose from the crater and drifted mainly SW. The plumes sometimes contained ash. Incandescence from the crater was sometimes visible at night. Two minor explosions were recorded at 0152 and 0559 on 21 April. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale).

Source: Centro Nacional de Prevencion de Desastres (CENAPRED)

Rincon de la Vieja | 20 April-26 April 2022 | Continuing ActivityCite this Report

Rincon de la Vieja
Costa Rica

OVSICORI-UNA reported that a small eruptive event at Rincón de la Vieja was recorded at 0618 on 25 April, though it was not visible due to weather conditions. Another small event was recorded at 0156 on 26 April; the plume was not visible due to conditions.

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

Sabancaya | 20 April-26 April 2022 | Continuing ActivityCite this Report

Sabancaya
Peru

Instituto Geofísico del Perú (IGP) reported moderate levels of activity at Sabancaya during 18-24 April with a daily average of 37 explosions. Gas-and-ash plumes rose as high as 2.3 km above the summit and drifted N, NE, SE, and S. As many as 10 thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. Minor inflation continued to be detected near Hualca Hualca (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)

Santa Maria | 20 April-26 April 2022 | Continuing ActivityCite this Report

Santa Maria
Southwestern Guatemala

INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 21-25 April. Incandescence from Caliente crater and the lava flows on the W and SW flanks was visible nightly and early mornings. Avalanches of blocks descended the W and SW flanks of Caliente. The lava flows continued to advance, traveling as far as 2.5 km in the San Isidro channel, and produced block avalanches from the ends and sides of the flows that descended the S, SW, and S flanks. Ash from these avalanches fell in areas around the volcano and a sulfur odor was also occasionally noticed.

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

Semeru | 20 April-26 April 2022 | Continuing ActivityCite this Report

Semeru
Eastern Java

PVMBG reported that the eruption at Semeru continued during 19-26 April. Almost daily ash plumes were visible rising 200-600 m above the summit that drifted N, S, SW, and W. Cloudy weather sometimes prevented visual observations. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 500 m away from Kobokan drainages within 17 km of the summit, along with other drainages originating on Semeru, 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)

Semisopochnoi | 20 April-26 April 2022 | Continuing ActivityCite this Report

Semisopochnoi
Aleutian Islands (USA)

AVO reported that low-level eruptive activity at Semisopochnoi's North Cerberus cone continued during 19-26 April. Periods of seismic tremor were occasionally detected and small explosions were recorded in seismic data during 19-20 April. Minor, low-level, plumes with low ash content were visible in webcam images through each day during 19-20 April, with occasional more energetic ash plumes. Weather cloud cover often hindered webcam and satellite views during the rest of the week. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Sheveluch | 20 April-26 April 2022 | Continuing ActivityCite this Report

Sheveluch
Central Kamchatka (Russia)

KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 15-22 April, and lava-dome extrusion continued. Explosions during 15-16 April produced ash plumes that rose as high as 5 km (16,400 ft) a.s.l. and drifted about 75 km SE. 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)

Suwanosejima | 20 April-26 April 2022 | Continuing ActivityCite this Report

Suwanosejima
Ryukyu Islands (Japan)

JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 18-25 April. Eruption plumes rose as high as 1.5 km above the crater rim; no explosions were recorded. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.

Source: Japan Meteorological Agency (JMA)

Wolf | 20 April-26 April 2022 | Continuing ActivityCite this Report

Wolf
Isla Isabela (Galapagos)

IG reported that thermal anomalies over Wolf were periodically identified in satellite images during 19-26 April, though were absent on several of the days. Lava advancement was identified in images during 19-21 April; no surface activity was visible the rest of the week.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

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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 Edgecumbe
AVO stated that a seismic swarm beneath Kruzof Island near Edgecumbe that began at about 0200 on 11 April had declined to background levels by 22 April. The swarm prompted an in-depth analysis of satellite data which spanned the last 7.5 years. The data showed that a broad area of uplift, about 17 km in diameter, was located about 2.5 km E of Edgecumbe. The uplift began in August 2018 and deformed at a rate of up to 8.7 cm per year in the center of the area, totaling 27 cm of uplift; the deformation was ongoing. Retrospective analysis of seismic data revealed that earthquakes started occurring in 2020, though the recent swarm was unusual. The deformation and seismic data together suggested magma movement beneath the volcano, consistent with an intrusion at about 5 km below sea level. The closest seismic station to the volcano was on Sitka, 24 km E; both the Volcano Alert Level and Aviation Color Code remained at Unassigned due to the lack of dedicated, local instrumentation.
Source: US Geological Survey Alaska Volcano Observatory (AVO)

Report for Karymsky
KVERT reported that a thermal anomaly over Karymsky was visible in satellite images during 15-22 April. Explosions during 17-19 and 21 April generated ash plumes that rose as high as 7.5 km (24,600 ft) a.s.l. and drifted 500 km NE. SE, and E. A powerful explosion at 0805 on 20 April (local time) generated ash plumes that rose as high as 11 km (36,100 ft) a.s.l. and drifted more than 2,000 km NE. KVERT raised the Aviation Color Code to Red (the highest level on a four-color scale). Ashfall was reported in the territory of the Kronotsky Reserve (Semyachinsky, Valley of Geysers), 50 km NE, and at Cape Nalychevo, 100 km S. Explosions continued through the day; ash plumes rising to 5 km (16,400 ft) a.s.l. were visible in satellite images at 1500, local time. The previous ash plume was about 505 x 130 km and drifted NE, S, and SE at an altitude of 8.7 km (28,500 ft) a.s.l. The Aviation Color Code was lowered to Orange by 1544, local time, on 20 April.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Report for Krakatau
PVMBG reported that the eruption at Anak Krakatau had intensified. Dense white, gray, and black ash plumes rose as high as 1 km above the summit and drifted SW during 17-19 April. Strombolian activity was first observed on 17 April; that same day that sulfur dioxide emissions increased to 181.1 tons per days from 28.4-68.4 tons per day recorded during 14-15 April. A dense gray-black ash plume rose around 800 m above the summit at 0621 on 21 April and drifted E. At 0049, 0145, 0237, and 1730 on 22 April dense gray-to-black ash plumes rose 500-1,500 m above the summit and drifted SW. Incandescent material was occasionally ejected above the vent. Sulfur dioxide emissions notably increased to 9,219 tons per day on 23 April. That same day, at around 1219, lava flowed into the sea and produced a white steam plume at the entry point. Ash plumes were taller on 23 April, rising to 3 km above the summit at 0608, 1200, and 2020, with SSW, S, and SE drifts. The plumes continued to be characterized as dense, and white, gray, and black in color. On 24 April PVMBG raised the Alert Level to 3 (on a scale of 1-4), and the public was warned to stay at least 5 km away from the crater.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Purace
Observatorio Vulcanológico y Sismológico de Popayán, Servicio Geologico Colombiano (SGC), reported that during 19-25 April the number and magnitudes of earthquakes at Puracé was similar to the previous week. Signals included 72 volcano-tectonic (VT) events, indicating rock fracturing, along with 207 long-period (LP) events and 14 low-energy tremor pulses, indicating fluid movement. Data from the GNSS (Global Navigation Satellite System) geodetic network continued to show inflation on the centimeter scale. Sulfur dioxide emissions were lower than the previous week, with values of 937-992 tonnes per day, and gas plumes drifted NW. During a field visit on 22 April scientists observed no changes to the crack near Puracé and Curiquinga volcanoes, and no visible gas emissions. Additional cracks, oriented NW-SE, were observed, in addition to volcanic ash deposits that were likely emplaced on 29 March. The Alert Level remained at Yellow (the second lowest on a four-color scale).
Source: Servicio Geológico Colombiano (SGC)

Report for Ruapehu
On 26 April GeoNet reported that elevated unrest at Ruapehu had been ongoing for the past five weeks, characterized by lake water heating, volcanic gas output, and strong volcanic tremor. Tremor levels fluctuated the past week but represented a record for the longest and strongest tremor episode ever recorded at the volcano. The lake water temperature remained at 37 degrees Celsius, indicating a substantial amount of heat from magma at a shallow depth (0.5-2 km), though water chemistry showed no change based on sampling during 31 March-15 April. The Volcanic Alert Level remained at 2 (on a scale from 0-5) and the Aviation Color Code remained at Yellow.
Source: GeoNet

Report for Aira
JMA reported that very small eruptive events at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) were recorded during 18-25 April. Crater incandescence was periodically visible at night. The sulfur dioxide emissions were slightly high at 1,300 tons per day on 19 April but then dropped to 500 tons per day on 22 April. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)

Report for Davidof
AVO lowered both the Aviation Color Code and the Volcano Alert Level for Davidof to Unassigned on 21 April, noting that the earthquake swarm which began in January had declined in the previous few weeks. It is unknown if the swarm was due to tectonic processes or volcanic unrest. The level “Unassigned” means that there is not sufficient instrumentation on the volcano for AVO to characterize a base level of activity; the closest seismometer was on Little Sitkin (15 km E).
Source: US Geological Survey Alaska Volcano Observatory (AVO)

Report for Dukono
Based on satellite and wind model data, the Darwin VAAC reported that during 21-23 and 25 April ash plumes from Dukono rose to 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: Darwin Volcanic Ash Advisory Centre (VAAC), Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Fuego
INSIVUMEH reported that 2-10 explosions per hour were recorded at Fuego during 21-25 April, generating ash plumes that rose as high as 1.3 km above the crater rim. The ash plumes mainly drifted as far as 15 km SE, S, and SW causing daily ashfall in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Sangre de Cristo (8 km WSW), Finca Palo Verde, Finca la Asunción, El Zapote (10 km S), San Pedro Yepocapa (8 km NW), Ceylon, San Andrés Osuna, and La Rochela. Shock waves rattled structures in communities around the volcano on most days and occasional rumbling was heard. Block avalanches descended the flanks in all directions, but most commonly were visible in the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Honda, and Las Lajas (SE) drainages, often reaching vegetated areas. Explosions ejected incandescent material 100-350 m above the summit during 21-24 April.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Report for Great Sitkin
AVO reported that slow lava effusion at Great Sitkin continued during 20-26 April, and very low seismicity persisted. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.
Source: US Geological Survey Alaska Volcano Observatory (AVO)

Report for Ibu
PVMBG reported that the eruption at Ibu continued during 22-26 April. Daily dense gray ash plumes generally rose 400-1,500 m above the summit and drifted W and NE, though at 0948 on 25 April ash plumes rose up to 3 km above the summit and drifted W. The Alert Level remained at a 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: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Kilauea
HVO reported that lava continued to effuse from a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 19-26 April, entering an active lava lake and flowing onto the crater floor. The surface of the lava lake was active all week, and the height of the lake fluctuated; the lake occasionally overflowed the rim, sending lava onto the crater floor. Daily breakouts occurred along the N, NE, E, and S parts of the crater. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Report for Langila
The Darwin VAAC reported that on 24 April an ash plume from Langila rose 2.1 km (7,000 ft) a.s.l. and drifted SW. The plume had dissipated within 5.5 hours.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Lewotolok
PVMBG reported that the eruption at Lewotolok continued during 19-26 April. Daily white-and-gray ash plumes rose 50-400 m above the summit and drifted W, NW, and E. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit crater and 4 km away from the crater on the SE flank.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Merapi
BPPTKG reported that the eruption at Merapi continued during 15-21 April. The heights and morphologies of the SW lava dome and the central lava dome were unchanged from the previous week, and seismicity remained at high levels. As many as 150 lava avalanches traveled a maximum of 2 km mostly down the Bebeng drainage on the SW flank. One pyroclastic flows traveled 2 km SW down the Bebeng. 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 Pavlof
AVO reported that the eruption at a vent on Pavlof’s upper E flank was ongoing during 20-26 April, though weather conditions sometimes prevented visual observations. Seismic tremor persisted and daily elevated surface temperatures were identified in satellite images. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.
Source: US Geological Survey Alaska Volcano Observatory (AVO)

Report for Popocatepetl
CENAPRED reported that the eruption at Popocatépetl continued during 19-26 April. Each day there were 6-27 steam-and-gas emissions that rose from the crater and drifted mainly SW. The plumes sometimes contained ash. Incandescence from the crater was sometimes visible at night. Two minor explosions were recorded at 0152 and 0559 on 21 April. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale).
Source: Centro Nacional de Prevencion de Desastres (CENAPRED)

Report for Rincon de la Vieja
OVSICORI-UNA reported that a small eruptive event at Rincón de la Vieja was recorded at 0618 on 25 April, though it was not visible due to weather conditions. Another small event was recorded at 0156 on 26 April; the plume was not visible due to conditions.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

Report for Sabancaya
Instituto Geofísico del Perú (IGP) reported moderate levels of activity at Sabancaya during 18-24 April with a daily average of 37 explosions. Gas-and-ash plumes rose as high as 2.3 km above the summit and drifted N, NE, SE, and S. As many as 10 thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. Minor inflation continued to be detected near Hualca Hualca (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 Santa Maria
INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 21-25 April. Incandescence from Caliente crater and the lava flows on the W and SW flanks was visible nightly and early mornings. Avalanches of blocks descended the W and SW flanks of Caliente. The lava flows continued to advance, traveling as far as 2.5 km in the San Isidro channel, and produced block avalanches from the ends and sides of the flows that descended the S, SW, and S flanks. Ash from these avalanches fell in areas around the volcano and a sulfur odor was also occasionally noticed.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Report for Semeru
PVMBG reported that the eruption at Semeru continued during 19-26 April. Almost daily ash plumes were visible rising 200-600 m above the summit that drifted N, S, SW, and W. Cloudy weather sometimes prevented visual observations. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 500 m away from Kobokan drainages within 17 km of the summit, along with other drainages originating on Semeru, 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 Semisopochnoi
AVO reported that low-level eruptive activity at Semisopochnoi's North Cerberus cone continued during 19-26 April. Periods of seismic tremor were occasionally detected and small explosions were recorded in seismic data during 19-20 April. Minor, low-level, plumes with low ash content were visible in webcam images through each day during 19-20 April, with occasional more energetic ash plumes. Weather cloud cover often hindered webcam and satellite views during the rest of the week. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.
Source: US Geological Survey Alaska Volcano Observatory (AVO)

Report for Sheveluch
KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 15-22 April, and lava-dome extrusion continued. Explosions during 15-16 April produced ash plumes that rose as high as 5 km (16,400 ft) a.s.l. and drifted about 75 km SE. 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 Suwanosejima
JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 18-25 April. Eruption plumes rose as high as 1.5 km above the crater rim; no explosions were recorded. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)

Report for Wolf
IG reported that thermal anomalies over Wolf were periodically identified in satellite images during 19-26 April, though were absent on several of the days. Lava advancement was identified in images during 19-21 April; no surface activity was visible the rest of the week.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)