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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 18 May-24 May 2022
Name Country Volcanic Province Eruption Start Date Report Status
Bezymianny Russia Eastern Kamchatka Volcanic Arc 2016 Dec 5 New
Cleveland United States Aleutian Ridge Volcanic Arc — New
Krakatau Indonesia Sunda Volcanic Arc — New
Reykjanes Iceland Iceland Neovolcanic Rift Zone 2023 Dec 18 New
Aira Japan Ryukyu Volcanic Arc 2017 Mar 25 Continuing
Dukono Indonesia Halmahera Volcanic Arc 1933 Aug 13 Continuing
Etna Italy Sicily Volcanic Province — Continuing
Fuego Guatemala Central America Volcanic Arc 2002 Jan 4 Continuing
Great Sitkin United States Aleutian Ridge Volcanic Arc 2021 May 25 Continuing
Ibu Indonesia Halmahera Volcanic Arc 2008 Apr 5 Continuing
Karymsky Russia Eastern Kamchatka Volcanic Arc — Continuing
Katmai United States Alaska Peninsula Volcanic Arc — Continuing
Kilauea United States Hawaiian-Emperor Hotspot Volcano Group — Continuing
Lewotolok Indonesia Sunda Volcanic Arc 2020 Nov 27 Continuing
Manam Papua New Guinea Bismarck Volcanic Arc 2014 Jun 29 Continuing
Merapi Indonesia Sunda Volcanic Arc 2020 Dec 31 Continuing
Nevados de Chillan Chile Andean Southern Volcanic Arc — Continuing
Pavlof United States Aleutian Ridge Volcanic Arc — Continuing
Rincon de la Vieja Costa Rica Central America Volcanic Arc 2021 Jun 28 Continuing
Ruapehu New Zealand Taupo Volcanic Zone — Continuing
Semeru Indonesia Sunda Volcanic Arc 2017 Jun 6 Continuing
Semisopochnoi United States Aleutian Ridge Volcanic Arc — Continuing
Sheveluch Russia Eastern Kamchatka Volcanic Arc 1999 Aug 15 Continuing
Suwanosejima Japan Ryukyu Volcanic Arc 2004 Oct 23 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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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)

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Report for Bezymianny
On 24 May KVERT reported that the effusive eruption at Bezymianny continued, characterized by strong fumarolic emissions, lava-dome incandescence, and hot avalanches. Notable hot avalanches descended the E flank. Gas-and-steam plumes with some ash content drifted 30 km NW on 24 May and 25 km NE on 25 May, at altitudes of 3-4.5 km (9,800-14,800 ft) a.s.l. The Aviation Color Code was raised to 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 Cleveland
AVO reported that during 17-24 May almost daily elevated surface temperatures over Cleveland were identified in satellite images. Daily sulfur dioxide emissions were visible, and steam plumes rose from the crater during 22-24 May. A series of small, local earthquakes were detected on 18 May. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Krakatau
The Darwin VAAC reported that on 18 May a diffuse ash plume from Anak Krakatau rose to 2.4 km (8,000 ft) a.s.l. and drifted WNW based on satellite images and weather models. On 19 May a dense steam plume with diffuse ash rose to 2.4 km and drifted N.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Report for Reykjanes
IMO reported an ongoing seismic swarm and uplift on the Reykjanes Peninsula, indicative of a magma intrusion. Satellite data analysis indicated that 4-4.5 cm of uplift occurred during 27 April-21 May centered just NW of Mt. Thorbjorn. Magma was accumulating at depths of 4-5 km, and the intrusion was possibly 7-8 km long. During 22-23 May about 400 earthquakes were recorded; a M 3 earthquake was recorded at 1113 on 22 May and a M 3.5 earthquake was recorded at 0715 on 23 May, both were located about 3 km E of Mt. Thorbjorn. The Aviation Color Code for Reykjanes remained at Yellow.
Sources: Icelandic Meteorological Office (IMO), Icelandic National Broadcasting Service (RUV)
Report for Aira
JMA reported that a very small eruptive event was recorded at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) during 16-23 May. Crater incandescence was visible at night. At 0900 on 17 May an eruptive event produced a plume that rose 1.5 km above the crater rim. That same day the sulfur dioxide rate was slightly high at 1,700 tons per day. 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 17-20 May ash plumes from Dukono rose to 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted W and NW. The plumes on 17 May drifted 185 km W. 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 Etna
INGV reported that at around 1900 on 12 May a new vent opened along the N flank of Etna’s Southeast Crater (SEC) at an elevation of 3,250 m, and produced ash emissions that rose to 3.5 km (11,500 ft) a.s.l. and drifted SW. Small pyroclastic flows descended the flank. Lava effused from the vent and traveled N and NE into the snowy Valle del Leone, where lava blocks that rolled onto the snow caused steam plumes. The lava flow slowly advanced during 13-22 May, reaching 2,300-2,400 m elevation by 17 May. Discontinuous Strombolian activity of variable intensities occurred at SEC; ash emissions were visible during more intense phases, though the plumes dissipated rapidly.

A new lava flow emerged from the vent on the N flank at around 2300 on 17 May and traveled N and NE alongside the previous lava flow. During fieldwork conducted on 18 May, scientists observed that lava had reached an elevation of 2,700 m in the Valle del Leone. A new vent opened on the N flank of SEC by 1730 on 20 May, at 3,250 m elevation, just NW of the previous vent. The vent produced a small lava flow that curved N and NE, joining the previous flow. By 21 May lava flows were not advancing below the summit area, at elevations of 2,700-2,800. Strombolian activity of varying intensity continued at SEC; periodic ash emissions generated ashfall in areas as far as Catania. At 2305 on 21 May a pyroclastic flow from the 20 May vent traveled 700 m NNE. Ash emissions intensified during 0300-0400 on 22 May. By that evening, lava flows from the 12 May vent had ceased and the 20 May vent produced short lava flows.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Fuego
INSIVUMEH reported that on 23 May lahars descended Fuego in the Las Lajas drainage (SE), the Ceniza drainage (SSW), and the Honda drainage (E); all three lahars carried fine material along with tree trunks, branches, and blocks as large as 1.5 m in diameter.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Great Sitkin
AVO reported that the eruption at Great Sitkin continued during 17-24 May. Almost daily elevated surface temperatures were identified in satellite data, consistent with lava effusion. Steam emissions were visible during 23-24 May. 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 17-24 May. Daily gray-and-white ash plumes of variable densities generally rose 200-1,500 m above the summit and drifted in multiple directions. 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 Karymsky
KVERT reported that during 13-20 May daily explosions at Karymsky generated ash plumes that rose 3-9.5 km (9,800-31,200 ft) a.s.l. and drifted more than 450 km in various directions. A thermal anomaly over the volcano was visible in satellite images during 13-14 and 17-19 May. 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 20 May strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes blew unconsolidated ash WNW at an altitude up to 1.8 km (6,000 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 continued to effuse from a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 17-24 May, entering the active lava lake and flowing onto the crater floor. The surface of the lava lake was active all week, though the height of the lake was high and relatively stable. Breakouts of lava occurred along the E, N, NW, and W margins of the lake. 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
PVMBG reported that the eruption at Lewotolok continued during 17-24 May. Daily white steam plumes were visible rising 50-800 m above the summit and drifted multiple directions. White-and-gray emissions were visible on 19 and 21 May rose as high as 500 m above the summit and drifted SE, W, and NW. 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 Manam
The Darwin VAAC reported that during 17-19 May ash plumes from Manam rose to 2.4 km (8,000 ft) a.s.l. and drifted NW and W based on satellite images and weather models.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Report for Merapi
BPPTKG reported that the eruption at Merapi continued during 13-19 May. 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 82 lava avalanches traveled a maximum of 2 km, mostly down the Bebeng drainage on the SW flank. One pyroclastic flow traveled 2.5 km down the Bebeng drainage. Seismicity remained high. 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 Nevados de Chillan
SERNAGEOMIN reported low levels of activity at Nevados de Chillán during 1-15 May. The area of the lava dome on the floor of Nicanor Crater was 1,626 square meters, similar to measurements from March (1,665 square meters); deformation measurements indicated that extrusion had ceased. Crater incandescence was sometimes visible; thermal anomalies were identified in satellite images on 3, 5, 8, 10, 13, and 15 May. There were 217 explosions in the active crater recorded by the seismic network. The explosions mainly produced steam, though the plumes occasionally contained tephra. Material from explosive activity accumulated in the NE part of the crater. An energetic explosion on 16 May produced an ash plume that rose 900 m and pyroclastic flows that descended the SE, NE, and W flanks as far as 400 m. Seismicity remained at moderate levels. Sulfur dioxide emissions averaged 466 ± 54 tons per day, peaking at 802 tons per day on 7 May. An explosion was recorded on 21 May. The Alert Level remained at Yellow, the second lowest level on a four-color scale. ONEMI stated that Alert Level Yellow (the middle level on a three-color scale) remained in place for the communities of Pinto and Coihueco, noting that the public should stay at least 2 km away from the crater.
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI)
Report for Pavlof
AVO reported that the eruption at a vent on Pavlof’s upper E flank was ongoing during 17-24 May, and seismic tremor persisted. Daily elevated surface temperatures were identified in satellite images consistent with the effusion of short lava flows on the upper flank. 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 few small phreatic explosions at Rincón de la Vieja were recorded during the previous week. A phreatic explosion at 1343 on 18 May produced a steam-and-gas plume that rose 200 m above the crater rim. At 1710 on 19 May an eruptive event produced a gas-and-steam plume that rose 100 m above the summit. More small eruptive events at 0251 and 0443 on 21 May were recorded by seismic and infrasound instruments.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
Report for Ruapehu
On 24 May GeoNet reported that elevated unrest at Ruapehu continued, though at reduced levels. During the previous week the levels of volcanic tremor further declined, were variable, but remained above normal. The lake water temperature decreased from a peak of 41 degrees Celsius on 8 May to 30 degrees Celsius, showing a cooling trend. A gas measurement flight on 13 May confirmed continuing high levels of gas emissions, though at values lower than measured two weeks prior; sulfur dioxide and carbon dioxide flux rates were at 179 and 1,658 tonnes per day, respectively; data from new instruments confirmed that these levels remained elevated. 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 Semeru
PVMBG reported that the eruption at Semeru continued during 17-24 May. White plumes were occasionally visible rising 100-700 m above the summit. Several eruptive events (recorded at 0525 on 19 May, at 0552 on 20 May, at 0525 on 21 May, at 0632 on 22 May, and at 0624 on 23 May) produced ash plumes that rose 200-500 m above the summit and drifted S and SW. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 5 km away from the summit, and 500 m away from Kobokan drainages within 17 km of the summit, and 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 17-24 May. Seismicity continued to be elevated with intermittent tremor and several daily explosions recorded by infrasound and seismic instruments. Low-level ash emissions were visible in clear satellite images and webcam views; clouds sometimes obscured views towards the end of the week. A sulfur dioxide plume drifted 240 km N during 17-18 May, and sulfur dioxide emissions were detected during 23-24 May. 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 13-20 May, and lava-dome extrusion continued. 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 16-23 May. Eruption plumes rose as high as 1.9 km above the crater rim and material was ejected 400 m above the vent. Ash fell in Toshima village (3.5 km SSW) and in other areas within 5 km. Three explosions were recorded during 20-23 May and crater incandescence from the crater was visible at night. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Source: Japan Meteorological Agency (JMA)