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 6 April-12 April 2022
Name	Location	Eruption Start Date	Report Status
Bezymianny	Central Kamchatka (Russia)	2016 Dec 5	New
Poas	Costa Rica	2023 Dec 1	New
Purace	Colombia	—	New
Ruapehu	North Island (New Zealand)	—	New
Taal	Luzon (Philippines)	2024 Apr 12	New
Aira	Kyushu (Japan)	2017 Mar 25	Continuing
Dukono	Halmahera	1933 Aug 13	Continuing
Great Sitkin	Andreanof Islands (USA)	2021 May 25	Continuing
Heard	Kerguelen Plateau	2012 Sep 5 ± 4 days	Continuing
Kadovar	Northeast of New Guinea	—	Continuing
Karymsky	Eastern Kamchatka (Russia)	—	Continuing
Katmai	Alaska	—	Continuing
Kilauea	Hawaiian Islands (USA)	—	Continuing
Lewotolok	Lembata Island	2020 Nov 27	Continuing
Merapi	Central Java	2020 Dec 31	Continuing
Nevado del Ruiz	Colombia	2014 Nov 18	Continuing
Pavlof	Alaska Peninsula, Alaska	—	Continuing
Rincon de la Vieja	Costa Rica	2021 Jun 28	Continuing
Sabancaya	Peru	2016 Nov 6	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
Yasur	Vanuatu	1270 ± 110 years	Continuing

All times are local unless otherwise stated.

Bezymianny | 6 April-12 April 2022 | New Activity / Unrest Cite this Report

Bezymianny
Central Kamchatka (Russia)

KVERT reported that a daily thermal anomaly over Bezymianny was visible in satellite images during 2-8 April. Strong fumarolic activity, incandescence at the lava dome, and avalanches were also reported. 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)

Poas | 6 April-12 April 2022 | New Activity / Unrest Cite this Report

Poas
Costa Rica

OVSICORI-UNA reported that on 6 April at 0240 a phreatic explosion from a vent called “Orange Fumarola” located in a fumarolic field along the inner N crater wall at Poás generated a plume that rose 500 m above the crater rim. Activity lasted for three minutes. The event caused a small landslide that modified the vent. Some of the material from the landslide was deposited in a narrow strip about 100 m into the Boca A lake. Stirred sediment was visibly moving in convection cells, turning the lake water from green to a uniform milky gray color as the sediment mixed into the water. Subaerial fumarolic vents at the E and S parts of the lake more vigorously emitted gasses following the event and remained at that level at least through 12 April. Convection in the lake also continued. OVSICORI-UNA noted that satellite data acquired the day before the explosion showed a total of 500 tons of sulfur dioxide released from both Poás and Turrialba.

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

Purace | 6 April-12 April 2022 | New Activity / Unrest Cite this Report

Purace
Colombia

On 29 March Observatorio Vulcanológico y Sismológico de Popayán, Servicio Geologico Colombiano (SGC), reported that the number of earthquakes at Puracé had increased during the previous few weeks, and were characterized by volcano-tectonic (VT) events, indicating rock fracturing, and long-period (LP) and volcanic tremor (TR) events, indicating fluid movement. The number of events notably increased on 28 March, with 479 VT, 183 (LP), and 119 (TR) events in total. The magnitudes of events abruptly increased the next day; the largest event was a M 3.3 recorded at 1214 on 29 March. Two fractures opened on 29 March, each about 40 m long, and produced gas emissions detected by satellite; ash was reported by observers in the area. The fractures were located along Coconucos Volcanic Chain, between Puracé Volcano and Curiquinga Volcano. The Alert Level was raised to Yellow (the second lowest on a four-color scale) on 30 March.

Seismicity continued to be elevated through 4 April. The earthquakes were low magnitude, and located about 800 m SE of Puracé and beneath Curiquinga, at depths of 2 km on average. The number of events signifying fluid movement was increasing. GNSS (Global Navigation Satellite System) geodetic network and DInSAR (Differential Interferometry by Synthetic Aperture Radar) showed inflation on the millimeter scale. Sulfur dioxide and carbon dioxide emissions increased, based on satellite and ground-based sampling data, and a fumarole on the N flank of Puracé intensified and produced a strong sulfur odor.

Significant unrest continued during 5-11 April. The seismic network recorded a total of 2,077 earthquakes, consisting of 248 VT events, 1,759 LP events, 37 low-energy TR events, and 31 hybrid events. Millimeter-scale inflation persisted, and sulfur dioxide emissions averaged 1,800 tonnes per day.

Source: Servicio Geológico Colombiano (SGC)

Ruapehu | 6 April-12 April 2022 | New Activity / Unrest Cite this Report

Ruapehu
North Island (New Zealand)

On 12 April GeoNet reported that unrest at Ruapehu had intensified during the previous week, characterized by increased gas emissions, elevated tremor, and increasing crater lake water temperatures. Tremor levels were elevated but had declined from the peak reached during 6-7 April. Higher levels of gas emissions were confirmed during an overflight on 11 April; a peak carbon dioxide value was the second highest ever recorded at Ruapehu. Lake temperatures continued to slowly climb and reached 38 degrees Celsius. The lake water was gray in color and had area of upwelling over the N vents; sulfur slicks on the lake’s surface were visible. GeoNet noted that temperature and modeled heat input to the lake were within typical ranges for a heating cycle, though the elevated tremor levels and gas emissions suggested that magma was interacting with the geothermal system. The Volcanic Alert Level remained at 2 (on a scale from 0-5) and the Aviation Color Code remained at Yellow.

Source: GeoNet

Taal | 6 April-12 April 2022 | New Activity / Unrest Cite this Report

Taal
Luzon (Philippines)

PHIVOLCS lowered the Alert Level for Taal to 2 (on a scale of 0-5) on 9 April, noting a significant decrease in activity during the previous two weeks. Sulfur dioxide emissions were high during the first three weeks of March, peaking at 21,211 tonnes per day on 16 March, but dropped on 3 April to an average of 240 tonnes per day; the flux again decreased to 103 tonnes per day on 8 April, the lowest number recorded since unrest began in 2021. During 26 March-9 April only 86 small-magnitude and imperceptible volcanic earthquakes had been recorded, and by 31 March background tremor associated with shallow hydrothermal activity had ceased. Electronic tilt monitoring on Taal Volcano Island, continuous Global Positioning System (GPS) data, and InSAR analysis of Sentinel-1 satellite data indicated continuing deflation of Taal, particularly on the SE flank. Diffuse plumes from the lake had also decreased in frequency, though they rose 600-900 m above the surface during 10-12 April. Sulfur dioxide emissions were below instrumental detection limits on 11 April. PHIVOLCS reminded the public that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

Aira | 6 April-12 April 2022 | Continuing ActivityCite this Report

Aira
Kyushu (Japan)

JMA reported that incandescence at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 4-11 April. Very small eruptive events were recorded on 6 and 9 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)

Dukono | 6 April-12 April 2022 | Continuing ActivityCite this Report

Dukono
Halmahera

Based on satellite and wind model data, the Darwin VAAC reported that during 7-12 April ash plumes from Dukono rose to 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted NE and NW. 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)

Great Sitkin | 6 April-12 April 2022 | Continuing ActivityCite this Report

Great Sitkin
Andreanof Islands (USA)

AVO reported that slow lava effusion at Great Sitkin continued during 5-12 April and very low seismicity persisted. The lava flows on the S, W, and N flanks had advanced up to 10 m during 2-8 April, and elevated surface temperatures identified in satellite images during 8-10 April indicated continuing effusion. Steaming from the vent and flow field was occasionally identified in satellite images. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Heard | 6 April-12 April 2022 | Continuing ActivityCite this Report

Heard
Kerguelen Plateau

Satellite images of Heard Island’s Big Ben volcano showed thermal anomalies of varying intensity over Mawson Peak (the summit area) and on the NW flank during the previous month. Weather clouds prevented views of the volcano for 11 of the 14 acquisitions during 11 March-13 April. On 11 March a small thermal anomaly at the peak was visible along with a larger anomaly over a vent or multiple vents about 1 km W; the larger anomaly was elongated NE-SW, suggesting a lava flow. Multiple anomalies in the same areas were visible on 31 March and 13 April.

Source: Sentinel Hub

Kadovar | 6 April-12 April 2022 | Continuing ActivityCite this Report

Kadovar
Northeast of New Guinea

Based on satellite and wind model data, the Darwin VAAC reported that on 8 April an ash plume from Kadovar rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SE.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Karymsky | 6 April-12 April 2022 | Continuing ActivityCite this Report

Karymsky
Eastern Kamchatka (Russia)

KVERT reported that a thermal anomaly over Karymsky was visible in satellite images on 3 and 5-6 April; the volcano was quiet or obscured by clouds on the other days during 1-8 April. 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)

Katmai | 6 April-12 April 2022 | Continuing ActivityCite this Report

Katmai
Alaska

AVO reported that on 8 April strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes blew unconsolidated ash SE towards Kodiak Island at an altitude up to 2.4 km (8,000 ft) a.s.l. The ash was originally deposited during the Novarupta eruption in 1912. The Volcano Alert Level remained at Normal and the Aviation Color Code remained at Green.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Kilauea | 6 April-12 April 2022 | Continuing ActivityCite this Report

Kilauea
Hawaiian Islands (USA)

HVO reported that lava effusion from a vent in the lower W wall of Kilauea’s Halema`uma`u Crater continued at variable rates during 5-12 April. Lava from a vent flowed into the active W part of the lava lake, which comprised about 2.3 percent of the total crater floor’s surface, and onto the crater floor. The surface of the lava lake was active all week, and the height of the lake fluctuated. Numerous ooze outs of lava were visible along the lake’s NW, NE, E, and SE margins; a more substantial ooze-out at the N margin was active during 6-7 April. A small outbreak at the W vent was visible overnight during 8-9 April. Just after 2300 on 10 April a flow emerged from the S side on the vent that covered areas along the southwest and western margins through 12 April. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Lewotolok | 6 April-12 April 2022 | Continuing ActivityCite this Report

Lewotolok
Lembata Island

The eruption at Lewotolok continued during 5-12 April according to PVMBG. Daily white-and-gray ash plumes with variable densities rose as high as 500 m above the summit and drifted E, NW, and W. Photos posted by PVMBG showed nighttime crater incandescence and incandescent material being ejected. 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.

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

Merapi | 6 April-12 April 2022 | Continuing ActivityCite this Report

Merapi
Central Java

BPPTKG reported no significant morphological changes at Merapi’s summit lava dome during 1-7 April. Based on photo analyses, the volume of the SW lava dome was 1.7 million cubic meters while the central lava dome was 2.6 million cubic meters. Seismicity remained at high levels. As many as 144 lava avalanches originating from the SW dome traveled a maximum of 2 km down the Bebeng drainage on the SW flank. A single pyroclastic flow traveled 1.5 km down the SW flank. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-5 km away from the summit based on location.

Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG)

Nevado del Ruiz | 6 April-12 April 2022 | Continuing ActivityCite this Report

Nevado del Ruiz
Colombia

Servicio Geológico Colombiano’s (SGC) reported that at 1713 on 11 April a seismic signal at Nevado del Ruiz was recorded along with an ash, gas, and steam plume. The plume rose almost 3.3 km above the summit and drifted N, causing minor ashfall around the volcano as reported by Parque Nacional Natural Los Nevados staff. It was also visible in webcam images and from the city of Manizales, 28 km NW. The Alert Level remained at 3 (Yellow; the second lowest level on a four-color scale).

Source: Servicio Geológico Colombiano (SGC)

Pavlof | 6 April-12 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 5-12 April, and seismic tremor persisted. Elevated surface temperatures were identified in satellite images almost daily. Possible minor lava effusion was visible in satellite images on 6 April, and a few small explosions were recorded each day during 6-9 April. Low-level ash emissions were visible in webcam and satellite images during 6-7 April, and satellite images captured ash and pyroclastic flow deposits extending at most 1.5 km from the vent and short lava flows on 9 April. Steam emissions from the vent were visible during 8-10 April. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Rincon de la Vieja | 6 April-12 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 0136 on 6 April, though the event was not visible due to poor visibility. Two small phreatic eruptions were recorded on 7 April at 1141 and 1323, based on webcam data. The resulting plumes rose 1,000 m and 500 m above the crater, respectively.

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

Sabancaya | 6 April-12 April 2022 | Continuing ActivityCite this Report

Sabancaya
Peru

Instituto Geofísico del Perú (IGP) reported moderate levels of activity at Sabancaya during 4-10 April with a daily average of 52 explosions. Gas-and-ash plumes rose as high as 2.5 km above the summit and drifted E, SE, and S. Three 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)

Semeru | 6 April-12 April 2022 | Continuing ActivityCite this Report

Semeru
Eastern Java

PVMBG reported that the eruption at Semeru continued during 5-12 April. Ash plumes rose 0.4-1 km above the summit during 6 and 8-12 April and drifted N. NW, and SW. 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 | 6 April-12 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 6-12 April. Periods of seismic tremor were detected daily and occasional small explosions were recorded on most days in seismic and regional infrasound data. Partly-to-mostly-cloudy webcam views and occasional satellite images showed daily short-lived ash bursts and more continuous steam emissions. Steam plumes drifted as far as 70 km SW during 6-7 April. A low-level steam plume drifted more than 100 km at altitudes less than 1.5 km (5,000 ft) a.s.l. during 7-8 April. A low-level ash plume drifted up to 80 km WNW on 8 April. Local ash deposits were occasionally visible. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Sheveluch | 6 April-12 April 2022 | Continuing ActivityCite this Report

Sheveluch
Central Kamchatka (Russia)

KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 2-8 April. The lava dome continued to grow and strong fumarolic activity, incandescence, and avalanches accompanied this activity. 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 | 6 April-12 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 4-8 April. Two explosions produced eruption plumes that rose as high as 3.3 km above the crater rim and ejected blocks as far as 500 m from the crater. Ashfall was reported in Toshima village (3.5 km SSW). No eruptive activity was noted during 9-11 April, though emissions rose 700 m. 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 | 6 April-12 April 2022 | Continuing ActivityCite this Report

Wolf
Isla Isabela (Galapagos)

IG reported that the eruption at Wolf continued during 5-12 April. Minor sulfur dioxide emissions were recorded during 5-6 April. Thermal data captured and mapped on 6 April indicated that lava flows were getting closer to the coast; daily thermal alert counts, as many as around 154, indicated active and advancing lava flows during the rest of the week.

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

Yasur | 6 April-12 April 2022 | Continuing ActivityCite this Report

Yasur
Vanuatu

The Wellington VAAC reported that during 9 and 11-12 April ash-and-steam emissions from Yasur were intermittently visible in webcam and satellite images rising 0.9-1.8 km (3,000-6,000 ft) a.s.l. and drifting SE.

Source: Wellington Volcanic Ash Advisory Center (VAAC)

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Criteria & Disclaimers

Criteria

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

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

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

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

Disclaimers

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

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

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

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Acronyms and Abbreviations

a.s.l. - above sea level

AVO - Alaska Volcano Observatory

AVHRR - Advanced Very High Resolution Radiometer

CENAPRED - Centro Nacionale de Prevencion de Desastres (México)

CONRED - Coordinadora Nacional para la Reducción de Desastres

COSPEC - Correlation Spectrometer

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

CVO - Cascades Volcano Observatory (USGS)

GMS - Geostationary Meteorological Satellite

GOES - Geostationary Operational Environmental Satellite

GVO - Goma Volcano Observatory

GVP - Global Volcanism Program (Smithsonian Institution)

HVO - Hawaiian Volcano Observatory (USGS)

ICE - Instituto Costarricense de Electricidad (Costa Rica)

IG - Instituto Geofísico (Ecuador)

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

INETER - Instituto Nicaragüense de Estudios Territoriales (Nicaragua)

INGEMMET - Instituto Geológical Minero y Metalúrgico (Peru)

INGEOMINAS - Instituto Colombiano de Geología y Minería (Colombia)

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

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

IRD - Institut de Recherche pour le Développement (France)

JMA - Japanese Meteorological Agency

KEMSD - Kamchatkan Experimental and Methodical Seismilogical Department

KVERT - Kamchatkan Volcanic Eruption Response Team

M - magnitude

METEOSAT - Meteorological Satellite

MEVO - Mount Erebus Volcano Observatory

MODIS - Moderate Resolution Imaging Spectroradiometer

MVO - Montserrat Volcano Observatory

MWO - Meteorological Watch Office

NEIC - National Earthquake Information Center

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

NOAA - National Oceanic and Atmospheric Administration

NOTAM - Notice to Airmen

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

OFDA - Office of US Foreign Disaster Assistance

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

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

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

PHIVOLCS - Philippine Institute of Volcanology and Seismology (Philippines)

RSAM - Real-time Seismic Amplitude Measurement

RVO - Rabaul Volcano Observatory

SERNAGEOMIN - Servicio Nacional de Geologia y Mineria (Chile)

SIGMET - Significant Meteorological Information

SNET - Servicio Nacional de Estudios Territoriales (El Salvador)

SVERT - Sakhalin Volcanic Eruption Response Team (Russia)

USAID - US Agency for International Development

USGS - United States Geological Survey

UTC - Coordinated Universal Time

VAAC - Volcanic Ash Advisory Center

VAFTAD - Volcanic Ash Forecast Transport And Dispersion

VDAP - Volcano Disaster Assistance Program (USGS)

VHP - Volcano Hazards Program (USGS)

VRC - Volcano Research Center (Japan)

Report for Bezymianny
KVERT reported that a daily thermal anomaly over Bezymianny was visible in satellite images during 2-8 April. Strong fumarolic activity, incandescence at the lava dome, and avalanches were also reported. 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
OVSICORI-UNA reported that on 6 April at 0240 a phreatic explosion from a vent called “Orange Fumarola” located in a fumarolic field along the inner N crater wall at Poás generated a plume that rose 500 m above the crater rim. Activity lasted for three minutes. The event caused a small landslide that modified the vent. Some of the material from the landslide was deposited in a narrow strip about 100 m into the Boca A lake. Stirred sediment was visibly moving in convection cells, turning the lake water from green to a uniform milky gray color as the sediment mixed into the water. Subaerial fumarolic vents at the E and S parts of the lake more vigorously emitted gasses following the event and remained at that level at least through 12 April. Convection in the lake also continued. OVSICORI-UNA noted that satellite data acquired the day before the explosion showed a total of 500 tons of sulfur dioxide released from both Poás and Turrialba.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

Report for Purace
On 29 March Observatorio Vulcanológico y Sismológico de Popayán, Servicio Geologico Colombiano (SGC), reported that the number of earthquakes at Puracé had increased during the previous few weeks, and were characterized by volcano-tectonic (VT) events, indicating rock fracturing, and long-period (LP) and volcanic tremor (TR) events, indicating fluid movement. The number of events notably increased on 28 March, with 479 VT, 183 (LP), and 119 (TR) events in total. The magnitudes of events abruptly increased the next day; the largest event was a M 3.3 recorded at 1214 on 29 March. Two fractures opened on 29 March, each about 40 m long, and produced gas emissions detected by satellite; ash was reported by observers in the area. The fractures were located along Coconucos Volcanic Chain, between Puracé Volcano and Curiquinga Volcano. The Alert Level was raised to Yellow (the second lowest on a four-color scale) on 30 March.

Seismicity continued to be elevated through 4 April. The earthquakes were low magnitude, and located about 800 m SE of Puracé and beneath Curiquinga, at depths of 2 km on average. The number of events signifying fluid movement was increasing. GNSS (Global Navigation Satellite System) geodetic network and DInSAR (Differential Interferometry by Synthetic Aperture Radar) showed inflation on the millimeter scale. Sulfur dioxide and carbon dioxide emissions increased, based on satellite and ground-based sampling data, and a fumarole on the N flank of Puracé intensified and produced a strong sulfur odor.

Significant unrest continued during 5-11 April. The seismic network recorded a total of 2,077 earthquakes, consisting of 248 VT events, 1,759 LP events, 37 low-energy TR events, and 31 hybrid events. Millimeter-scale inflation persisted, and sulfur dioxide emissions averaged 1,800 tonnes per day.
Source: Servicio Geológico Colombiano (SGC)

Report for Ruapehu
On 12 April GeoNet reported that unrest at Ruapehu had intensified during the previous week, characterized by increased gas emissions, elevated tremor, and increasing crater lake water temperatures. Tremor levels were elevated but had declined from the peak reached during 6-7 April. Higher levels of gas emissions were confirmed during an overflight on 11 April; a peak carbon dioxide value was the second highest ever recorded at Ruapehu. Lake temperatures continued to slowly climb and reached 38 degrees Celsius. The lake water was gray in color and had area of upwelling over the N vents; sulfur slicks on the lake’s surface were visible. GeoNet noted that temperature and modeled heat input to the lake were within typical ranges for a heating cycle, though the elevated tremor levels and gas emissions suggested that magma was interacting with the geothermal system. 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 Taal
PHIVOLCS lowered the Alert Level for Taal to 2 (on a scale of 0-5) on 9 April, noting a significant decrease in activity during the previous two weeks. Sulfur dioxide emissions were high during the first three weeks of March, peaking at 21,211 tonnes per day on 16 March, but dropped on 3 April to an average of 240 tonnes per day; the flux again decreased to 103 tonnes per day on 8 April, the lowest number recorded since unrest began in 2021. During 26 March-9 April only 86 small-magnitude and imperceptible volcanic earthquakes had been recorded, and by 31 March background tremor associated with shallow hydrothermal activity had ceased. Electronic tilt monitoring on Taal Volcano Island, continuous Global Positioning System (GPS) data, and InSAR analysis of Sentinel-1 satellite data indicated continuing deflation of Taal, particularly on the SE flank. Diffuse plumes from the lake had also decreased in frequency, though they rose 600-900 m above the surface during 10-12 April. Sulfur dioxide emissions were below instrumental detection limits on 11 April. PHIVOLCS reminded the public that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ).
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

Report for Aira
JMA reported that incandescence at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 4-11 April. Very small eruptive events were recorded on 6 and 9 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 Dukono
Based on satellite and wind model data, the Darwin VAAC reported that during 7-12 April ash plumes from Dukono rose to 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted NE and NW. 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 Great Sitkin
AVO reported that slow lava effusion at Great Sitkin continued during 5-12 April and very low seismicity persisted. The lava flows on the S, W, and N flanks had advanced up to 10 m during 2-8 April, and elevated surface temperatures identified in satellite images during 8-10 April indicated continuing effusion. Steaming from the vent and flow field was occasionally identified in satellite images. 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 Heard
Satellite images of Heard Island’s Big Ben volcano showed thermal anomalies of varying intensity over Mawson Peak (the summit area) and on the NW flank during the previous month. Weather clouds prevented views of the volcano for 11 of the 14 acquisitions during 11 March-13 April. On 11 March a small thermal anomaly at the peak was visible along with a larger anomaly over a vent or multiple vents about 1 km W; the larger anomaly was elongated NE-SW, suggesting a lava flow. Multiple anomalies in the same areas were visible on 31 March and 13 April.
Source: Sentinel Hub

Report for Kadovar
Based on satellite and wind model data, the Darwin VAAC reported that on 8 April an ash plume from Kadovar rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SE.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Karymsky
KVERT reported that a thermal anomaly over Karymsky was visible in satellite images on 3 and 5-6 April; the volcano was quiet or obscured by clouds on the other days during 1-8 April. 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 Katmai
AVO reported that on 8 April strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes blew unconsolidated ash SE towards Kodiak Island at an altitude up to 2.4 km (8,000 ft) a.s.l. The ash was originally deposited during the Novarupta eruption in 1912. The Volcano Alert Level remained at Normal and the Aviation Color Code remained at Green.
Source: US Geological Survey Alaska Volcano Observatory (AVO)

Report for Kilauea
HVO reported that lava effusion from a vent in the lower W wall of Kilauea’s Halema`uma`u Crater continued at variable rates during 5-12 April. Lava from a vent flowed into the active W part of the lava lake, which comprised about 2.3 percent of the total crater floor’s surface, and onto the crater floor. The surface of the lava lake was active all week, and the height of the lake fluctuated. Numerous ooze outs of lava were visible along the lake’s NW, NE, E, and SE margins; a more substantial ooze-out at the N margin was active during 6-7 April. A small outbreak at the W vent was visible overnight during 8-9 April. Just after 2300 on 10 April a flow emerged from the S side on the vent that covered areas along the southwest and western margins through 12 April. 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 Lewotolok
The eruption at Lewotolok continued during 5-12 April according to PVMBG. Daily white-and-gray ash plumes with variable densities rose as high as 500 m above the summit and drifted E, NW, and W. Photos posted by PVMBG showed nighttime crater incandescence and incandescent material being ejected. 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.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Merapi
BPPTKG reported no significant morphological changes at Merapi’s summit lava dome during 1-7 April. Based on photo analyses, the volume of the SW lava dome was 1.7 million cubic meters while the central lava dome was 2.6 million cubic meters. Seismicity remained at high levels. As many as 144 lava avalanches originating from the SW dome traveled a maximum of 2 km down the Bebeng drainage on the SW flank. A single pyroclastic flow traveled 1.5 km down the SW flank. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-5 km away from the summit based on location.
Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG)

Report for Nevado del Ruiz
Servicio Geológico Colombiano’s (SGC) reported that at 1713 on 11 April a seismic signal at Nevado del Ruiz was recorded along with an ash, gas, and steam plume. The plume rose almost 3.3 km above the summit and drifted N, causing minor ashfall around the volcano as reported by Parque Nacional Natural Los Nevados staff. It was also visible in webcam images and from the city of Manizales, 28 km NW. The Alert Level remained at 3 (Yellow; the second lowest level on a four-color scale).
Source: Servicio Geológico Colombiano (SGC)

Report for Pavlof
AVO reported that the eruption at a vent on Pavlof’s upper E flank was ongoing during 5-12 April, and seismic tremor persisted. Elevated surface temperatures were identified in satellite images almost daily. Possible minor lava effusion was visible in satellite images on 6 April, and a few small explosions were recorded each day during 6-9 April. Low-level ash emissions were visible in webcam and satellite images during 6-7 April, and satellite images captured ash and pyroclastic flow deposits extending at most 1.5 km from the vent and short lava flows on 9 April. Steam emissions from the vent were visible during 8-10 April. 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 Rincon de la Vieja
OVSICORI-UNA reported that a small eruptive event at Rincón de la Vieja was recorded at 0136 on 6 April, though the event was not visible due to poor visibility. Two small phreatic eruptions were recorded on 7 April at 1141 and 1323, based on webcam data. The resulting plumes rose 1,000 m and 500 m above the crater, respectively.
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 4-10 April with a daily average of 52 explosions. Gas-and-ash plumes rose as high as 2.5 km above the summit and drifted E, SE, and S. Three 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 Semeru
PVMBG reported that the eruption at Semeru continued during 5-12 April. Ash plumes rose 0.4-1 km above the summit during 6 and 8-12 April and drifted N. NW, and SW. 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 6-12 April. Periods of seismic tremor were detected daily and occasional small explosions were recorded on most days in seismic and regional infrasound data. Partly-to-mostly-cloudy webcam views and occasional satellite images showed daily short-lived ash bursts and more continuous steam emissions. Steam plumes drifted as far as 70 km SW during 6-7 April. A low-level steam plume drifted more than 100 km at altitudes less than 1.5 km (5,000 ft) a.s.l. during 7-8 April. A low-level ash plume drifted up to 80 km WNW on 8 April. Local ash deposits were occasionally visible. 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 2-8 April. The lava dome continued to grow and strong fumarolic activity, incandescence, and avalanches accompanied this activity. 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 4-8 April. Two explosions produced eruption plumes that rose as high as 3.3 km above the crater rim and ejected blocks as far as 500 m from the crater. Ashfall was reported in Toshima village (3.5 km SSW). No eruptive activity was noted during 9-11 April, though emissions rose 700 m. 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 the eruption at Wolf continued during 5-12 April. Minor sulfur dioxide emissions were recorded during 5-6 April. Thermal data captured and mapped on 6 April indicated that lava flows were getting closer to the coast; daily thermal alert counts, as many as around 154, indicated active and advancing lava flows during the rest of the week.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

Report for Yasur
The Wellington VAAC reported that during 9 and 11-12 April ash-and-steam emissions from Yasur were intermittently visible in webcam and satellite images rising 0.9-1.8 km (3,000-6,000 ft) a.s.l. and drifting SE.
Source: Wellington Volcanic Ash Advisory Center (VAAC)