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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 25 May-31 May 2022
Name Location Eruption Start Date Report Status
Bezymianny Central Kamchatka (Russia) 2010 May 21 (?) New
Cleveland Chuginadak Island (USA) New
Dempo Southeastern Sumatra New
Yakedake Honshu (Japan) New
Aira Kyushu (Japan) 2017 Mar 25 Continuing
Ambae Vanuatu Continuing
Dukono Halmahera 1933 Aug 13 Continuing
Etna Sicily (Italy) Continuing
Fuego South-Central Guatemala 2002 Jan 4 Continuing
Gaua Banks Islands (Vanuatu) Continuing
Great Sitkin Andreanof Islands (USA) 2021 May 25 Continuing
Karymsky Eastern Kamchatka (Russia) Continuing
Kilauea Hawaiian Islands (USA) 2021 Sep 29 Continuing
Kuchinoerabujima Ryukyu Islands (Japan) Continuing
Lewotolok Lembata Island 2020 Nov 27 Continuing
Manam Northeast of New Guinea 2014 Jun 29 Continuing
Merapi Central Java 2020 Dec 31 Continuing
Pavlof Alaska Peninsula, Alaska 2021 Aug 5 Continuing
Rincon de la Vieja Costa Rica 2021 Jun 28 Continuing
Santa Maria Southwestern Guatemala 1922 Jun 22 Continuing
Semeru Eastern Java 2014 Apr 1 ± 15 days Continuing
Semisopochnoi Aleutian Islands (USA) Continuing
Sheveluch Central Kamchatka (Russia) 1999 Aug 15 Continuing
Stromboli Aeolian Islands (Italy) 1934 Feb 2 Continuing
Suwanosejima Ryukyu Islands (Japan) 2004 Oct 23 Continuing
Yasur Vanuatu 1774 Jul 2 (in or before) ± 182 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 18,412 individual reports over 1,143 weeks (average of 16 per week) on 328 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 Sundoro
Alaid Davidof Irazu Lopevi Puyehue-Cordon Caulle Suretamatai
Alu-Dalafilla Dempo Iya Machin Rabaul Suwanosejima
Ambae Descabezado Grande Izu-Torishima Makushin Raikoke Taal
Ambang Dieng Volcanic Complex Jackson Segment Maly Semyachik Ranakah Tair, Jebel at
Ambrym Dukono Kaba Manam Raoul Island Takawangha
Anatahan Ebeko Kadovar Manda Hararo Rasshua Talang
Aniakchak Ebulobo Kaitoku Seamount Marapi Raung Tambora
Antillanca Volcanic Complex Edgecumbe Kama'ehuakanaloa Maroa Redoubt Tanaga
Antuco Egon Kambalny Martin Reventador Tandikat-Singgalang
Apoyeque Ekarma Kanaga Masaya Reykjanes Tangkoko-Duasudara
Arenal Epi Kanlaon Maule, Laguna del Rincon de la Vieja Tangkuban Parahu
Asamayama Erebus Karangetang Mauna Loa Rinjani Tara, Batu
Askja Erta Ale Karkar Mayon Ritter Island Ta'u
Asosan Etna Karthala McDonald Islands Rotorua Taupo
Atka Volcanic Complex Etorofu-Yakeyama [Grozny Group] Karymsky Melimoyu Ruang Telica
Augustine Eyjafjallajokull Kasatochi Merapi Ruapehu Tenerife
Avachinsky Fagradalsfjall Katla Midagahara Ruiz, Nevado del Tengger Caldera
Awu Fernandina Katmai Misti, El Sabancaya Three Sisters
Axial Seamount Fogo Kavachi Miyakejima Sakar Tinakula
Azul, Cerro Fonualei Kelimutu Momotombo Salak Tofua
Azumayama Fournaise, Piton de la Kelud Monowai San Cristobal Tokachidake
Bagana Fourpeaked Kerinci Montagu Island San Miguel Tolbachik
Balbi Fuego Ketoi Moyorodake [Medvezhia] San Vicente Toliman
Bamus Fujisan Kharimkotan Mutnovsky Sangay Tongariro
Banda Api Fukutoku-Oka-no-Ba Kick 'em Jenny Myojinsho Sangeang Api Trident
Bardarbunga Galeras Kie Besi Nabro Santa Ana Tungurahua
Barren Island Galunggung Kikai Negra, Sierra Santa Maria Turrialba
Batur Gamalama Kilauea Negro, Cerro Sao Jorge Ubinas
Bezymianny Gamkonora Kirishimayama Nightingale Island Sarigan Ugashik-Peulik
Bogoslof Gareloi Kita-Ioto Nishinoshima Sarychev Peak Ukinrek Maars
Brava Gaua Kizimen Nisyros Saunders Ulawun
Bristol Island Gorely Klyuchevskoy Novarupta Savo Unnamed
Bulusan Great Sitkin Kolokol Group NW Rota-1 Semeru Unnamed
Calbuco Grimsvotn Koryaksky Nyamulagira Semisopochnoi Veniaminof
Callaqui Guagua Pichincha Krakatau Nyiragongo Seulawah Agam Villarrica
Cameroon Guallatiri Krummel-Garbuna-Welcker Ofu-Olosega Sheveluch Vulcano
Campi Flegrei del Mar di Sicilia Guntur Krysuvik-Trolladyngja Okataina Shishaldin West Mata
Cayambe Hachijojima Kuchinoerabujima Okmok Simbo Westdahl
Chachadake [Tiatia] Hakoneyama Kurikomayama Ontakesan Sinabung Whakaari/White Island
Chaiten Heard Kusatsu-Shiranesan Oraefajokull Sinarka Witori
Chiginagak Hekla Kverkfjoll Osorno Siple Wolf
Chikurachki Helgrindur La Palma Pacaya Sirung Yakedake
Chiles-Cerro Negro Hierro Lamington Pagan Slamet Yasur
Chillan, Nevados de Hokkaido-Komagatake Lamongan Palena Volcanic Group Snaefellsjokull Yufu-Tsurumi
Chirinkotan Home Reef Langila Paluweh Soputan Zaozan [Zaosan]
Chirpoi Hood Lanin Panarea Sorikmarapi Zavodovski
Ciremai Huaynaputina Lascar Papandayan Sotara Zhupanovsky
Cleveland Hudson, Cerro Lateiki Parker Soufriere Hills Zubair Group
Colima Huila, Nevado del Lengai, Ol Doinyo Pavlof Soufriere St. Vincent
Colo Hunga Tonga-Hunga Ha'apai Leroboleng Pelee South Sarigan Seamount
Concepcion Ibu Lewotobi Peuet Sague Spurr
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 Bezymianny
KVERT reported that the eruption at Bezymianny continued, characterized by strong fumarolic emissions, lava-dome incandescence, explosions, and hot avalanches. Seismicity increased during 23-28 May. Multiple and notable collapses of hot avalanches on the E flank produced ash plumes that rose to 4-5 km (13,100-16,400 ft) a.s.l. and drifted 70-320 km in multiple directions.

Activity significantly increased on 28 May, local time. According to Kamchatka Volcanological Station (Volkstat), observers saw ash plumes from Bezymianny rising over Klyuchevsky volcano around lunchtime. The plume altitudes gradually increased and late in the evening a large, strong, explosive event occurred; ash plumes rose to 11 km (36,100 ft) a.s.l. and drifted E. According to KVERT satellite data showed ash plumes rising 10-12 km (32,800-39,400 ft) a.s.l. and drifting ESE at 1920. The Aviation Color Code was raised to Red (the highest level on a four-color scale). By 2010 the ash plumes had risen to 15 km (49,000 ft) a.s.l., and previous ash emissions had drifted 365 km SE. Volkstat observers noted that activity began to decline by about 2020 and plume altitudes did not exceed 6 km (19,700 ft) a.s.l. and drifted SE. At 2207 KVERT issued a VONA noting that the Aviation Color Code was lowered to Orange as the most intense phase of the explosive eruption had ended. Ash plumes continued to be emitted, though they rose no higher than 5 km based on webcam views. Two ash plumes were identified in satellite images; the first was drifting 212 km SE at an altitude of 9.5 km (31,200 ft) a.s.l. and the second was drifting 650 km SE at unspecified altitudes. On 29 May at 1000 gas-and-steam plumes with some ash were visible in webcam images rising as high as 4.5 km a.s.l. and drifting 45 km SE. Satellite images showed that the large ash cloud from the day before had drifted 1,635 km SE.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Kamchatka Volcanological Station
Report for Cleveland
AVO reported that during 24-31 May daily elevated surface temperatures over Cleveland were identified in satellite images, along with plumes of steam and sulfur dioxide gas. Crater subsidence in the summit crater was detected during 26-27 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 Dempo
PVMBG reported that at 0154 on 31 May a phreatic eruption at Dempo produced ashfall in areas within 5 km, including Pagar Alam Utara district (E) and North Dempo District. Ash deposits were as thick as 1 mm. The Alert Level remained at 2 (on a scale of 1-4), and the public were reminded to stay 1 km away from the crater and as far as 2 km on the N flank.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Yakedake
JMA raised the Alert Level for Yakedake to 2 (on a scale of 1-5) on 24 May, noting that the number of small volcanic earthquakes with epicenters near the summit began increasing around 2300 the day before. The report also noted that minor inflation near the summit was continuing. Daily small volcanic earthquakes continued to be counted through 31 May.
Source: Japan Meteorological Agency (JMA)
Report for Aira
JMA reported that a very small eruptive event was recorded at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) during 23-30 May. Crater incandescence was visible at night during 23-27 May. 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 Ambae
On 27 May the Vanuatu Meteorology and Geo-Hazards (VMGD) reported that the cone in Ambae’s Lake Voui continued to produce steam and ash emissions. The Alert Level remained at 2 (on a scale of 0-5) and the public was warned to stay outside of the Danger Zone, defined as a 2-km radius around the active vents in Lake Voui, and away from drainages during heavy rains.
Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD)
Report for Dukono
Based on satellite and wind model data, the Darwin VAAC reported that during 26-28 and 30-31 May ash plumes from Dukono rose to 2.1-2.7 km (7,000-9,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.
Sources: Darwin Volcanic Ash Advisory Centre (VAAC), Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Etna
INGV reported that during 23-29 May activity at Etna’s Southeast Crater (SEC) was characterized by intermittent Strombolian activity and occasional ash emissions. At 0805 on 29 May a fissure opened in the upper part of the Valle del Bove. Two vents along the fissure, located at 2,850 and 2,730 m elevation, produced slow-moving lava flows that had advanced E to 2,090 m elevation by the next day. During an aerial survey conducted on 30 May scientists observed a series of about four arc-shaped fractures on the E flank of SEC, between 3,000 and 3,200 m elevation, and unstable and slumped material which had moved downslope.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Fuego
INSIVUMEH reported that 2-9 explosions per hour were recorded at Fuego during 24-31 May, generating ash plumes that rose as high as 1.1 km above the crater rim. The ash plumes drifted as far as 30 km in multiple directions, causing ashfall on most days in areas downwind including La Soledad (11 km N), Chimaltenango (21 km NNE), Parramos, Yepocapa (8 km N), Quisaché, Santa Isabel, La Rochela, El Zapote (10 km S), and La Trinidad (S). Ashfall was probable but not reported on three of the days. Daily shock waves rattled structures in communities around the volcano and occasional rumbling was heard. Block avalanches descended the upper flanks in all directions, but most commonly were visible in the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Honda, and Las Lajas (SE) drainages. Explosions ejected incandescent material 100-400 m above the summit on most days. Lahars descended the Ceniza and El Jute (SE) drainages during 27-28 May.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Gaua
On 27 May Vanuatu Meteorology and Geo-Hazards (VMGD) reported that steam emissions continued to be emitted at Gaua based on satellite images and local observers. The steam plumes may have contained volcanic gases. Alert Level remained at 2 (on a scale of 0-5) and the public was warned to stay away from the main cone.
Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD)
Report for Great Sitkin
AVO reported that the eruption at Great Sitkin continued during 24-31 May, though weather clouds sometimes hindered observations. Almost daily elevated surface temperatures were identified in satellite data, consistent with lava effusion, and satellite images during 28-29 May showed that the lava field had expanded. Steam emissions were occasionally visible. 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 Karymsky
KVERT reported that a thermal anomaly over Karymsky was identified in satellite images during 20 and 23-27 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 Kilauea
HVO reported that lava continued to effuse from a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 24-31 May, entering the lava lake and flowing onto the crater floor. The surface of the lava lake was continuously active all week, though the height of the lake was high and relatively stable. Nearly-continuous breakouts of lava occurred along the 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 Kuchinoerabujima
JMA lowered the Alert Level for Kuchinoerabujima to 1 (on a scale of 1-5) on 25 May, noting that the number of volcanic earthquakes had decreased to low levels. The report noted that sulfur dioxide emissions had continued to remain low, and that no changes in temperature or the extent of the geothermal areas around the crater were observed.
Source: Japan Meteorological Agency (JMA)
Report for Lewotolok
PVMBG reported that the eruption at Lewotolok continued during the month of May. White, gray, and black plumes rose as high as 1.2 km above the summit crater, and white-and-gray plumes rose 100-500 m. Lava flows were active on the crater floor. On 31 May lava flow breached the E crater rim and traveled 500 m E, towards the Jontona Village, located 4 km E of the summit. 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 Manam
The Darwin VAAC reported daily ash plumes at Manam during 25-29 May. At 0720 on 25 May an ash plume rose to 2.4 km (8,000 ft) a.s.l. and drifted W, and dissipated within 30 minutes. Ash plumes rose to 2.1 km (7,000 ft) a.s.l. and drifted NW during 25-26 May. An eruptive event, observed at 0657 on 27 May by RVO and webcam images, produced an ash plume that rose to 2.4 km a.s.l. based on webcam views; weather clouds prevented satellite views of the emissions. On 28 May an ash plume rose to 2.1 km a.s.l. and drifted NE. A thermal anomaly over the volcano was visible following the emission. On 29 May diffuse ash plumes rose to 2.1-2.4 km a.s.l. and drifted in multiple directions.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Report for Merapi
BPPTKG reported that the eruption at Merapi continued during 20-26 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 144 lava avalanches traveled a maximum of 2 km down the Bebeng drainage on the SW flank. Three pyroclastic flows traveled 2 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 Pavlof
AVO reported that the eruption at a vent on Pavlof’s upper E flank was ongoing during 24-31 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 E flank. An active flow that was 650 m long was visible in satellite images during 28-29 May. 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 several small phreatic explosions at Rincón de la Vieja were recorded during 25-28 May. A phreatic explosion at 1730 on 25 May produced minor ashfall on local plants located on the upper flanks. Weather conditions often prevented views of plumes.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
Report for Santa Maria
INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 23-31 May. Incandescence from Caliente crater and the lava flows on the W and SW flanks was visible nightly and during some early mornings. Avalanches of incandescent blocks descended the W, SW, and S flanks of Caliente. The lava flows continued to advance in the San Isidro channel, and produced block avalanches from the ends and sides of the flows that descended the S, SW, and S flanks. Ash from these avalanches fell in areas on and around the volcano. The lava flow was 3.3 km long by 27 May. Cement-like lahars descended the Cabello de Ángel drainage (a tributary of Nimá I on the SE flank) during 27-28 May, carrying tree trunks, branches, and blocks up to 1 m in diameter.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Semeru
PVMBG reported that the eruption at Semeru continued during 24-31 May. Several eruptive events (recorded at 0553 and 0627 on 28 May, at 0819 on 29 May, and at 0529 on 30 May) produced ash plumes that rose 300-600 m above the summit and drifted N 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 24-31 May. Seismicity continued to be elevated with intermittent tremor and several daily explosions recorded by infrasound and seismic instruments. Weather clouds often prevented satellite and webcam views; sporadic ash emissions were visible during 27-28 May and likely occurred on other days as well. Sulfur dioxide emissions were detected during 27-29 May, and elevated surface temperatures were identified during 28-29 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 20-27 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 Stromboli
INGV reported that during 23-29 May activity at Stromboli was characterized by ongoing explosions from four vents in Area N (North Crater area) and three vents in Area C-S (South-Central Crater area). During most of the week explosions from Area N vents (N1 and N2) averaged 3-6 events per hour; explosions from the N1 vent ejected lapilli and bombs 80-150 m high, and minor gas emissions and weak spattering was visible at N2 vents. No explosions occurred at the S1 and C vents in Area C-S (except for on 25 May); low- to medium-intensity explosions at the two S2 vents occurred at a rate of 0-4 per hour and ejected coarse material 80-150 m high. At 1611 on 25 May a high-energy explosive event occurred at the N vent in S2, ejecting material beyond the area viewed by the Pizzo webcam, located about 250 m elevation. A second explosion, recorded at 1612 at the C vent, ejected course material 80 m high.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Suwanosejima
JMA reported that 33 explosions were recorded at Suwanosejima's Ontake Crater during 23-30 May. Eruption plumes rose as high as 1.9 km above the crater rim and material was ejected 500 m above the vent. Crater incandescence was visible at night. Ash fell in Toshima village (3.5 km SSW) during 23-27 May. 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 Yasur
On 27 May Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur continued at a high level of “major unrest,” as defined by the Alert Level 2 status (the middle level on a scale of 0-4). Ash-and-gas emissions and loud explosions continued to be recorded, with bombs falling in and around the crater. The public was reminded to not enter the restricted area within 600 m around the cone, defined by Danger Zone A on the hazard map.
Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD)