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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 21 April-27 April 2021
Name Country Volcanic Province Eruption Start Date Report Status
Karymsky Russia Eastern Kamchatka Volcanic Arc New
Piton de la Fournaise France Reunion Hotspot Volcano Group New
Semisopochnoi United States Aleutian Ridge Volcanic Arc New
Soufriere St. Vincent Saint Vincent and the Grenadines Lesser Antilles Volcanic Arc New
Veniaminof United States Aleutian Ridge Volcanic Arc New
Aira Japan Ryukyu Volcanic Arc 2017 Mar 25 Continuing
Ebeko Russia Kuril Volcanic Arc 2022 Jun 11 Continuing
Etna Italy Sicily Volcanic Province Continuing
Fagradalsfjall Iceland Iceland Neovolcanic Rift Zone Continuing
Fuego Guatemala Central America Volcanic Arc 2002 Jan 4 Continuing
Kilauea United States Hawaiian-Emperor Hotspot Volcano Group Continuing
Lewotolok Indonesia Sunda Volcanic Arc 2020 Nov 27 Continuing
Merapi Indonesia Sunda Volcanic Arc 2020 Dec 31 Continuing
Pacaya Guatemala Central America Volcanic Arc Continuing
Semeru Indonesia Sunda Volcanic Arc 2017 Jun 6 Continuing
Sheveluch Russia Eastern Kamchatka Volcanic Arc 1999 Aug 15 Continuing
Sinabung Indonesia Sunda Volcanic Arc Continuing
Stromboli Italy Aeolian Volcanic Arc 1934 Feb 2 Continuing
Suwanosejima Japan Ryukyu Volcanic Arc 2004 Oct 23 Continuing
Villarrica Chile Andean Southern Volcanic Arc 2014 Dec 2 ± 7 days Continuing
All times are local unless otherwise stated.
Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 20,322 individual reports over 1,229 weeks (average of 17 per week) on 336 different volcanoes.

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Agung Cotopaxi Iliamna Little Sitkin Planchon-Peteroa Stromboli
Ahyi Cuicocha Iliwerung Llaima Poas Sulu Range
Aira Cumbal Inielika Lokon-Empung Popocatepetl Sumbing
Akan Dabbahu Ioto Lonquimay Purace Sumisujima
Alaid Davidof Irazu Lopevi Puyehue-Cordon Caulle Sundoro
Alu-Dalafilla Dempo Iya Machin Rabaul Suoh
Ambae Descabezado Grande Izu-Torishima Makushin Raikoke Suretamatai
Ambang Dieng Volcanic Complex Jackson Segment Maly Semyachik Ranakah Suwanosejima
Ambrym Dukono Kaba Manam Raoul Island Taal
Anatahan East Epi Kadovar Manda Hararo Rasshua Tair, Jebel at
Aniakchak Ebeko Kaitoku Seamount Marapi Raung Takawangha
Antillanca Volcanic Complex Ebulobo Kama'ehuakanaloa Maroa Redoubt Talang
Antuco Edgecumbe Kambalny Martin Reventador Tambora
Apoyeque Egon Kanaga Masaya Reykjanes Tanaga
Arenal Ekarma Kanlaon Matthew Island Rincon de la Vieja Tandikat-Singgalang
Asamayama Eldey Karangetang Maule, Laguna del Rinjani Tangkoko-Duasudara
Askja Erebus Karkar Mauna Loa Ritter Island Tangkuban Parahu
Asosan Erta Ale Karthala Mayon Rotorua Tara, Batu
Atka Volcanic Complex Etna Karymsky McDonald Islands Ruang Ta'u
Augustine Etorofu-Yakeyama [Grozny Group] Kasatochi Melebingoy Ruapehu Taupo
Avachinsky Eyjafjallajokull Katla Melimoyu Ruby Telica
Awu Fagradalsfjall Katmai Merapi Ruiz, Nevado del Tenerife
Axial Seamount Fernandina Kavachi Midagahara Sabancaya Tengger Caldera
Azul, Cerro Fogo Kelimutu Misti, El Sakar Three Sisters
Azumayama Fonualei Kelud Miyakejima Salak Tinakula
Bagana Fournaise, Piton de la Kerinci Momotombo San Cristobal Tofua
Balbi Fourpeaked Ketoi Monowai San Miguel Tokachidake
Bamus Fuego Kharimkotan Montagu Island San Vicente Tolbachik
Banda Api Fujisan Kick 'em Jenny Moyorodake [Medvezhia] Sangay Toliman
Bardarbunga Fukutoku-Oka-no-Ba Kie Besi Mutnovsky Sangeang Api Tongariro
Barren Island Galeras Kikai Myojinsho Santa Ana Trident
Batur Galunggung Kilauea Nabro Santa Maria Tungurahua
Bezymianny Gamalama Kirishimayama Negra, Sierra Sao Jorge Turrialba
Bogoslof Gamkonora Kita-Ioto Negro, Cerro Sarigan Ubinas
Brava Gareloi Kizimen Nightingale Island Sarychev Peak Ugashik-Peulik
Bristol Island Gaua Klyuchevskoy Nishinoshima Saunders Ukinrek Maars
Bulusan Gorely Kolokol Group Nisyros Savo Ulawun
Calbuco Great Sitkin Koryaksky Novarupta Semeru Unnamed
Callaqui Grimsvotn Krakatau NW Rota-1 Semisopochnoi Unnamed
Cameroon Guagua Pichincha Krummel-Garbuna-Welcker Nyamulagira Seulawah Agam Veniaminof
Campi Flegrei Guallatiri Krysuvik-Trolladyngja Nyiragongo Sheveluch Villarrica
Campi Flegrei del Mar di Sicilia Guntur Kuchinoerabujima Ofu-Olosega Shishaldin Vulcano
Cayambe Hachijojima Kurikomayama Okataina Simbo West Mata
Chachadake [Tiatia] Hakoneyama Kusatsu-Shiranesan Okmok Sinabung Westdahl
Chaiten Heard Kverkfjoll Ontakesan Sinarka Whakaari/White Island
Chiginagak Hekla La Palma Oraefajokull Siple Witori
Chikurachki Helgrindur Lamington Osorno Sirung Wolf
Chiles-Cerro Negro Hierro Lamongan Pacaya Slamet Wrangell
Chillan, Nevados de Hokkaido-Komagatake Langila Pagan Snaefellsjokull Yakedake
Chirinkotan Home Reef Lanin Palena Volcanic Group Soputan Yasur
Chirpoi Hood Lascar Paluweh Sorikmarapi Yellowstone
Ciremai Huaynaputina Late Panarea Sotara Yufu-Tsurumi
Cleveland Hudson, Cerro Lateiki Papandayan Soufriere Hills Zaozan [Zaosan]
Colima Huila, Nevado del Lengai, Ol Doinyo Pavlof Soufriere St. Vincent Zavodovski
Colo Hunga Tonga-Hunga Ha'apai Leroboleng Pelee South Sarigan Seamount Zhupanovsky
Concepcion Ibu Lewotobi Peuet Sague Spurr Zubair Group
Copahue Ijen Lewotolok Pinatubo St. Helens
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The RSS (Really Simple Syndication) feed is identical to the Weekly Volcanic Activity Report minus some features including the header information (latitude and longitude and summit elevation), the Geologic Summary, and a link to the volcano's page from the Global Volcanism Program. At the end of each report is a list of the sources used. Each volcano report includes a link from the volcano's name back to the more complete information in the Weekly Volcanic Activity Report on the Smithsonian website. This feature was first made available on 5 March 2008.



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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 Karymsky
KVERT reported that a weak thermal anomaly over Karymsky was visible in satellite images 16-17 and 22 April. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Report for Piton de la Fournaise
OVPF reported that the eruption at Piton de la Fournaise continued during 21-27 April, though inclement weather conditions obscured visual observations most of the week. The average lava-flow rate was between 1.2 and 8.3 cubic meters per second during 16-23 April. The flow rates were estimated based on the gas-emission rates, though weather conditions may have affected the accuracy of the measurements. Lava continued to mostly flow in lava tubes; some flows thickened and parts of the flow field widened. The longest flow was 3.2 km long and the maximum width was 750 m, unchanged from the previous week. The flow field was mapped using a satellite image acquired on 24 April. The Alert Level remained at 2-2.
Source: Observatoire Volcanologique du Piton de la Fournaise (OVPF)
Report for Semisopochnoi
Eruptive activity at Semisopochnoi gradually increased during 21-22 April based on satellite and infrasound data; ash emissions were first seen in satellite images at 1800 on 21 April and were continuous at least through 1348 on 22 April. Plumes rose to 2.4 km (8,000 ft) a.s.l. and drifted 80 km S. Sulfur dioxide emissions were also detected in satellite images on 22 April. Cloud cover mostly obscured views during 23-24 April, though possible minor ash emissions were sometimes visible. Low-level ash plumes drifting S were occasionally identified in satellite images during 24-26 April. Dense weather clouds prevented views for most of 26 April and the next day. 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 Soufriere St. Vincent
University of the West Indies Seismic Research Centre (UWI-SRC) reported that eruptive activity at Soufrière St. Vincent (often simply referred to as “La Soufriere”) was relatively low during 21-27 April with the exception of one explosive period. During 20-21 April seismicity was characterized by a few rockfalls and volcano-tectonic (VT) earthquakes, and an increasing number of small long-period (LP) and hybrid earthquakes. Sulfur dioxide emissions were again measured from a boat near the W coast, revealing a flux of 350 tons per day. At around 1108 on 22 April explosions produced an ash plume that rose as high as 8 km (26,200 ft) a.s.l. and drifted mainly N over the sea. High-level seismic tremor began at 1109 and lasted for about 20 minutes. Pyroclastic flows were generated early in the eruption and traveled down the W flank, reaching the sea within five minutes. Lahar signals were recorded later that day at about 2100. According to National Emergency Management Organisation (NEMO) the total number of displaced people was 13,154 by 21 April, with 6,208 people in 85 public shelters and 6,790 people (1,618 families) in private shelters. There were no casualties caused by the eruption. In a 22 April press release the Argyle International Airport announced that the ash cleanup was ongoing and that the Cargo Terminal was scheduled to open the next day.

Seismicity dropped to low levels after the explosive event and remained at low levels through 27 April; only a few LP, hybrid and VT earthquakes were recorded. On 23 April the sulfur dioxide flux was 992 tons per day, recorded again from the W coast. A diffuse steam plume rose from the crater on 24 April. Satellite data most recently from 24 April, and seismic data suggested likely cycles of crater dome growth and destruction. During an overflight on 26 April scientists observed white steam plumes rising from several locations on the crater floor, though visibility was poor. No lava dome was visible, but a possible spine-like protrusion was seen through the clouds. Seismic signals indicating lahars were again recorded. Lahars in the Red and Orange zones were recorded by the seismic network at 0900 and 1000 on 27 April, during and after rainfall. The volcano Alert Level remained at Red.
Sources: University of the West Indies Seismic Research Centre (UWI-SRC), National Emergency Management Organisation (NEMO), Government of Saint Vincent and the Grenadines, Advanced geospatial Data Management Platform (ADAM), Argyle International Airport Inc.
Report for Veniaminof
AVO reported that eruptive activity at Veniaminof had declined during the previous few weeks; no emissions were visible after ash emissions on 5 April and seismicity continued to decline. On 21 April the Volcano Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Aira
JMA reported that during 19-26 April incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible nightly. There was a total of 16 explosions, producing ash plumes that rose as high as 2.3 km above the summit and ejected bombs 1-1.3 km away from the crater. The sulfur dioxide emission rate was somewhat high at 1,800 tons per day on 21 April. An explosion at 0109 on 25 April produced what was initially thought to be a pyroclastic flow, triggering JMA to warn residents beyond a 2-km radius to be cautious and vigilant. Scientists conducting field observations later that day did not observe pyroclastic flow deposits or damaged vegetation, and concluded that the plume phenomenon was generated by winds. 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 Ebeko
Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 16-18 and 22 April that sent ash plumes to 3 km (10,000 ft) a.s.l. and drifted NE, E, and SW. Ash fell in Severo-Kurilsk on 16 April. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Report for Etna
INGV reported that during 19-25 April activity at Etna was mainly characterized by gas emissions rising from the summit craters, though inclement weather conditions often prevented visual observations. Bocca Nuova in particular produced frequent steam puffs. A strong explosion at 0030 on 25 April from the E vent of Southeast Crater (SEC) ejected incandescent material up to 350 m above the crater rim. An ash plume dispersed to the S.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Fagradalsfjall
IMO reported that the fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 21-27 April. A M 4.1 earthquake was recorded at 2305 on 21 April about 6 km WSW of the fissures and followed by several aftershocks; it was the largest on the Reykjanes Peninsula since 15 March, before the eruption began. The average lava-flow rate was calculated by the University of Iceland’s Institute of Earth Sciences using photographs most recently collected during an overflight on 26 April. They reported that during the previous five days the flow rate from all of the active craters averaged just over 6 cubic meters per second; the average rate during the 38 days of the eruption was 5.6 cubic meters per second. The area of the flow field was 1.13 square kilometers, the total volume was over 18.4 million cubic meters, with an average thickness of just over 16 m. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions.
Source: Icelandic Meteorological Office (IMO)
Report for Fuego
INSIVUMEH reported that 5-14 explosions were recorded per hour during 21-27 April at Fuego, generating ash plumes as high as 1.1 km above the crater rim. Shock waves rattled buildings around the volcano, especially in areas as far as 20 km W and SW. Block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Las Lajas (SE), and Honda drainages, often reaching vegetated areas. Ashfall was reported on most days in several 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), and San Pedro Yepocapa (8 km NW). Explosions ejected incandescent material 100-400 m above the summit almost daily.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Kilauea
HVO reported that the W vent on the inner NW wall of Kilauea's Halema`uma`u Crater continued to supply the lava lake during 21-27 April. Lava flowed at a low rate from the main vent into the lake through crusted-over channels and submerged inlets. The depth of the lake was about 226-227 m and lava continued to circulate in the W part, though the active area continued to shrink; the E half of the lake remained solidified. Lava sometimes overflowed the margins of the lake. The sulfur dioxide emission rate was 350, 550, 300, and 350 tons/day on 21, 22, 23, and 24 April, respectively. The rates were the lowest measured during the eruption, though elevated above the levels recorded in the months before the start of the eruption (20 December 2020). The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Report for Lewotolok
PVMBG reported that the eruption at Lewotolok continued during 20-27 April. Black, gray, and white plumes rose as high as 1 km above the summit and drifted E, SE, and W on most days. 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 that the lava dome just below Merapi’s SW rim and the lava dome in the summit crater both continued to extrude lava during 16-22 April. The SW rim lava-dome volume was an estimated 1,069,600 cubic meters on 21 April, with a growth rate of about 11,900 cubic meters per day; the dome continued to shed material down the flank. A total of nine pyroclastic flows traveled a maximum of 1.8 km down the SW flank. Incandescent avalanches, recorded 144 times, traveled as far as 1.6 km down the SW flank and twice down the SE flank as far as 400 m. The volume of the summit lava dome was 1,794,000 cubic meters on 22 April. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 5 km away from the summit.
Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG)
Report for Pacaya
INSIVUMEH reported that during 20-21 April explosions at Pacaya’s Mackenney Crater generated minor gas-and-ash plumes that rose 250 m above the summit and drifted S and SW. The lava flow on the SW flank continued to be active, though did not advance. White gas plumes were visible the next day rising as high as 200 m. On 23 April lava effusion ceased. The lava flows on the SW flank remained hot and gas plumes rose from parts of the flow; no advancement was visible through 27 April. Gray-and-white emissions were visible during 24-27 April, rising 100-200 m above the summit and dispersing S and SW. Occasional minor explosions ejected incandescent material 50-150 m high during 26-27 April.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Semeru
PVMBG reported that during 21-22 and 24-25 April ash plumes from Semeru rose 500-700 m above the summit and drifted SW, S, and SE. The Alert Level remained at 2 (on a scale of 1-4), with a general exclusion zone of 1 km and extensions to 5 km in the SSE sector.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Sheveluch
KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 16-23 April. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Report for Sinabung
PVMBG reported that the eruption at Sinabung continued during 21-27 April. Weather conditions sometimes prevented visual observations of the volcano, though white fumarolic plumes were visible almost daily rising as high as 700 m above the summit and drifted E and SE. Pyroclastic flows traveled 2 km on 21 April. Avalanches of material traveled 1 km E and SE during 23-24 April. Ash plumes rose 2 km above the summit on 24 April and to 1 km on 25 April, drifting ESE both days. The Alert Level remained at 3 (on a scale of 1-4), with a general exclusion zone of 3 km and extensions to 5 km in the SE sector and 4 km in the NE sector.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Stromboli
INGV reported that during 19-25 April activity at Stromboli was characterized by ongoing explosive activity from Area N (North Crater area) and in Area C-S (South-Central Crater area), though sometime weather conditions prevented visual observations. Explosions from two vents in the N1 vent (Area N) ejected lapilli and bombs 250 m high, and produced minor ash emissions. Explosions at N2 vents (Area N) averaged 11-14 events per hour. Periods of visible spattering were most notable on 24 April. Explosions from at least three vents in Area C-S occurred at a rate of 1-5 events per hour and ejected coarse material more than 250 m high.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Suwanosejima
JMA reported that incandescence from Suwanosejima's Ontake Crater was occasionally visible at night during 16-23 April. Five explosions generated ash plumes that rose as high as 1.7 km above the crater rim and ejected bombs 600 m away. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)
Report for Villarrica
SERNAGEOMIN reported that during 1-15 April gas-and-steam emissions with no or very small amounts of ash rose from Villarrica to heights less than 1.2 km above the crater rim. Crater incandescence was not visible at night and sulfur dioxide emissions were low. Observations from multiple sources suggested that the lava lake level was lower, decreasing the likelihood that material ejected by minor explosions would reach beyond 100 m from the crater. The Alert Level was lowered to Green on 23 April, the lowest level on a four-color scale. ONEMI declared a “Preventative Early Warning” for the municipalities of Villarrica, Pucón (16 km N), Curarrehue, and the commune of Panguipulli, and the exclusion zone for the public of 100 m around the crater.
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI)