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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 5 May-11 May 2021
Name Location Eruption Start Date Report Status
Bulusan Luzon (Philippines) New
Nevados de Chillan Chile 2016 Jan 8 New
Piton de la Fournaise Reunion Island (France) New
Aira Kyushu (Japan) 2017 Mar 25 Continuing
Ebeko Paramushir Island (Russia) 2016 Oct 20 Continuing
Fuego Guatemala 2002 Jan 4 Continuing
Karymsky Eastern Kamchatka (Russia) 2021 Apr 3 Continuing
Kilauea Hawaiian Islands (USA) Continuing
Krysuvik-Trolladyngja Iceland 2021 Mar 19 Continuing
Lewotolok Lembata Island (Indonesia) 2020 Nov 27 Continuing
Merapi Central Java (Indonesia) 2020 Dec 31 Continuing
Pacaya Guatemala 2015 Jun 7 ± 1 days Continuing
Sangay Ecuador 2019 Mar 26 Continuing
Santa Maria Guatemala 1922 Jun 22 Continuing
Semeru Eastern Java (Indonesia) 2014 Apr 1 ± 15 days Continuing
Semisopochnoi Aleutian Islands (USA) Continuing
Sheveluch Central Kamchatka (Russia) 1999 Aug 15 Continuing
Sinabung Indonesia 2020 Aug 8 Continuing
Soufriere St. Vincent St. Vincent Continuing
Suwanosejima Ryukyu Islands (Japan) 2004 Oct 23 Continuing
Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 16,844 individual reports over 1,072 weeks (average of 16 per week) on 311 different volcanoes.

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Agung Copahue Ijen Little Sitkin Pelee South Sarigan Seamount
Ahyi Cotopaxi Iliamna Llaima Peuet Sague Spurr
Aira Cuicocha Iliwerung Loihi Pinatubo St. Helens
Akan Cumbal Inielika Lokon-Empung Planchon-Peteroa Stromboli
Alaid Dabbahu Ioto Lopevi Poas Sulu Range
Alu-Dalafilla Dempo Irazu Machin Popocatepetl Sumbing
Ambae Descabezado Grande Iya Makian Puyehue-Cordon Caulle Sundoro
Ambang Dieng Volcanic Complex Izu-Torishima Makushin Rabaul Suretamatai
Ambrym Dukono Jackson Segment Maly Semyachik Raikoke Suwanosejima
Anatahan Ebeko Kaba Manam Ranakah Taal
Antillanca Volcanic Complex Ebulobo Kadovar Manda Hararo Raoul Island Tair, Jebel at
Antuco Egon Kambalny Marapi Rasshua Takawangha
Apoyeque Ekarma Kanaga Maroa Raung Talang
Arenal Epi Kanlaon Martin Redoubt Tambora
Asamayama Erebus Karangetang Masaya Reventador Tanaga
Askja Erta Ale Karkar Maule, Laguna del Reykjanes Tandikat-Singgalang
Asosan Etna Karthala Mauna Loa Rincon de la Vieja Tangkoko-Duasudara
Augustine Etorofu-Yakeyama [Grozny Group] Karymsky Mayon Rinjani Tangkuban Parahu
Avachinsky Eyjafjallajokull Kasatochi McDonald Islands Ritter Island Tara, Batu
Awu Fernandina Katla Melimoyu Rotorua Telica
Axial Seamount Fogo Katmai Merapi Ruang Tenerife
Azul, Cerro Fonualei Kavachi Midagahara Ruapehu Tengger Caldera
Azumayama Fournaise, Piton de la Kelimutu Misti, El Ruiz, Nevado del Three Sisters
Bagana Fourpeaked Kelut Miyakejima Sabancaya Tinakula
Balbi Fuego Kerinci Momotombo Sakar Tofua
Bamus Fujisan Ketoi Monowai Salak Tokachidake
Banda Api Fukutoku-Oka-no-Ba Kharimkotan Montagu Island San Cristobal Tolbachik
Bardarbunga Galeras Kick 'em Jenny Moyorodake [Medvezhia] San Miguel Toliman
Barren Island Galunggung Kikai Mutnovsky San Vicente Tongariro
Batur Gamalama Kilauea Myojinsho Sangay Tungurahua
Bezymianny Gamkonora Kirishimayama Nabro Sangeang Api Turrialba
Bogoslof Gareloi Kizimen Negra, Sierra Santa Ana Ubinas
Brava Gaua Klyuchevskoy Negro, Cerro Santa Maria Ugashik-Peulik
Bristol Island Gorely Kolokol Group Nightingale Island Sarigan Ukinrek Maars
Bulusan Great Sitkin Korovin Nishinoshima Sarychev Peak Ulawun
Calbuco Grimsvotn Koryaksky Nisyros Saunders Unnamed
Callaqui Guagua Pichincha Krakatau Novarupta Semeru Unnamed
Cameroon Guallatiri Krummel-Garbuna-Welcker NW Rota-1 Semisopochnoi Veniaminof
Campi Flegrei del Mar di Sicilia Guntur Krysuvik-Trolladyngja Nyamulagira Seulawah Agam Villarrica
Cayambe Hachijojima Kuchinoerabujima Nyiragongo Sheveluch West Mata
Cereme Hakoneyama Kurikomayama Okataina Shishaldin Westdahl
Chachadake [Tiatia] Heard Kusatsu-Shiranesan Okmok Simbo Whakaari/White Island
Chaiten Hekla Kverkfjoll Ontakesan Sinabung Witori
Chiginagak Helgrindur Lamington Oraefajokull Sinarka Wolf
Chikurachki Hierro Lamongan Osorno Siple Yasur
Chiles-Cerro Negro Hokkaido-Komagatake Langila Pacaya Sirung Zaozan [Zaosan]
Chillan, Nevados de Home Reef Lanin Pagan Slamet Zavodovski
Chirinkotan Hood Lascar Palena Volcanic Group Snaefellsjokull Zhupanovsky
Chirpoi Huaynaputina Lateiki Paluweh Soputan Zubair Group
Cleveland Hudson, Cerro Lengai, Ol Doinyo Panarea Sorikmarapi
Colima Huila, Nevado del Leroboleng Papandayan Sotara
Colo Hunga Tonga-Hunga Ha'apai Lewotobi Parker Soufriere Hills
Concepcion Ibu Lewotolok Pavlof Soufriere St. Vincent
 News Feeds and Google Placemarks


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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 monthly, and 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 Bulusan
PHIVOLCS stated that unrest at Bulusan had increased, noting that 62 volcanic earthquakes were recorded during 7-10 May and 124 were recorded during 10-11 May. Inflation of the upper flanks first recorded on 6 March in tilt data was sustained. GPS data indicated short-term inflation starting in late February, though the long-term pattern since July 2019 showed deflation. The data suggested shallow hydrothermal processes. The Alert Level for Bulusan was raised to 1 on 11 May, reflecting abnormal conditions, and the public was reminded not to enter the 4-km-radius Permanent Danger Zone (PDZ).
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
Report for Nevados de Chillan
SERNAGEOMIN noted that sulfur dioxide emissions and thermal anomalies at Nevados de Chillán’s Nicanor Crater had both increased in March, and inflation began on 27 March. During the second half of April the dome grew at a higher rate, with growth concentrated on the W part. The dome was 66 m high at the center. The L5 lava flow advanced and was about 940 m long, and 50 m thick near the flow front. The effusion rate increased on 28 April. During 2-5 May activity was characterized by increased crater incandescence and a series of intense explosions that destroyed part of the summit lava dome. Dense ash plumes rose above the crater. Block-and-ash flows traveled less than 400 m down the NE flank and pyroclastic flows traveled short distances SW. During 4-5 May the effusion rate increased and the L5 lava flow advanced. A new lava flow (L6) emerged on 5 May from the summit crater and descended 100 m down the NE flank. A high-temperature elongated deposit in between the L5 and L6 flows was visible in infrared images. 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 Piton de la Fournaise
OVPF reported that the eruption at Piton de la Fournaise continued during 4-11 May. Both craters were active, producing lava flows that mainly traveled though lava tubes. Lava emerged from the end of the flow field, advancing E to 1,200 m elevation by 8 May, and setting fire to local vegetation. Minor inflation of the summit area was recorded. Lava fountaining was weak at the smaller vent to the SE and a small lava pond continued to occupy the crater of the larger cone, just NW a higher elevation. Gas plumes rose from both craters, though the plumes from the smaller crater were denser. An 11 May report stated that the larger cone was 35 m tall and 226 m in diameter at its base. The Alert Level remained at 2-2.
Source: Observatoire Volcanologique du Piton de la Fournaise (OVPF)
Report for Aira
JMA reported that during 3-10 May incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible nightly. There were four explosions and four non-explosive events during 3-7 May, producing ash plumes that rose as high has 2.5 km above the summit and ejecting bombs 0.8-1.1 km away from the crater. Very small eruptive events were recorded during 7-10 May. The sulfur dioxide emission rate was 1,300 tons per day on 19 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 Ebeko
Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 4-6 May that sent ash plumes to 2.5 km (8,200 ft) a.s.l. and drifted N and SE. A thermal anomaly was identified in satellite data on 5 May. 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 Fuego
INSIVUMEH reported that 5-12 explosions per hour were recorded during 4-11 May at Fuego, generating ash plumes as high as 1.1 km above the crater rim. Shock waves sometimes rattled buildings around the volcano. Ashfall was reported daily 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). Block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Las Lajas (SE), and Honda drainages, often reaching vegetated areas. Explosions ejected incandescent material 100-450 m above the summit during 4-8 May.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Karymsky
KVERT reported that a weak thermal anomaly over Karymsky was visible in satellite images during 29-30 April and 1 May; weather clouds prevented observations during 2-7 May. 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 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 at a low rate during 5-11 May through a submerged inlet. The depth of the lake was 229 m by 11 May. Lava continued to circulate in the W part, though the active area continued to shrink. The E half of the lake remained solidified and comprised about 93 percent of the total area, based on thermal measurements acquired on 16 April. The sulfur dioxide emission rate was 200-300 tons per day during 5-7 May, and 150 tons per day on 10 May, continuing a downward trend that began in mid-April. 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 Krysuvik-Trolladyngja
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 5-11 May. On 2 May pulsating high jets of lava from crater 5 prompted authorities to widen the restricted zone because; ash and lava could be deposited several hundred of meters away. Cycles of lava jetting and effusion periodically continued during 3-7 May, with lava steadily enlarging the flow field. By 4 May the area of the flow field had grown to 1.41 square kilometers, and the total volume erupted was 23 million cubic meters. Activity was quiet for a period of time during 8-9 May, though IMO noted that fountaining quickly resumed during the morning of 9 May. High jets of lava occurred every 10 minutes, sometimes with jets rising as high as 300 m. Tephra (a few centimeters in diameter) was deposited as far as 1 km from the vent and small amounts of tephra were reported in Gríndavík. Hot deposits have caused small vegetation fires within a few hundreds of meters around the eruption site. On 10 May gas plumes rose higher than 2 km a.s.l. The eruption area was closed due to local wildfires and unfavorable wind conditions. Very high fountains were visible in Reykjavik. On 11 May lava fountains again rose up to 300 m tall and were seen from the capital. The cone had grown to about 50 m high. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions.
Sources: Icelandic Meteorological Office (IMO), Icelandic National Broadcasting Service (RUV), Institute of Earth Sciences
Report for Lewotolok
PVMBG reported that mostly white plumes from Lewotolok rose as high as 600 m and drifted SE, W, and NW during 4-11 May. Gray-and-white plumes rose 500 m and drifted W, NW, and SE on 6 and 8 May. 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 30 April-6 May. The SW rim lava-dome volume was an estimated 1.1 million cubic meters on 2 May, with a growth rate of about 17,000 cubic meters per day, and continued to shed material down the flank. A total of 12 pyroclastic flows traveled a maximum of 2 km down the SW flank. Incandescent avalanches, recorded 74 times, traveled as far as 2 km down the SW flank and twice went 600 m SE. The volume of the summit lava dome was 1.7 million cubic meters on 2 May, with a growth rate of about 14,000 cubic meters per day. Electronic Distance Measurement (EDM) data showed a distance shortening between points in the NW at a rate of 0.6 cm per day, indicating minor inflation. 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 4-11 May the lava flow on Pacaya’s N flank continued to advance, lengthening from 2.1 to 2.4 km, and spreading laterally in some areas. Incandescent blocks detached from the flow, especially along the flow margins and steep slopes. Occasional explosions at the vent (near Cerro Chino) ejected incandescent material as high as 100 m. Around 0600 on 6 May explosions at the summit produced ash plumes that drifted S. Dense ash plumes were visible drifting W and SW during 7-9 May. On 11 May an advancing lava flow on the SW flank was 2.3 km long.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Sangay
IG reported a high level of activity at Sangay during 5-11 May. Seismicity was characterized by 3-28 daily explosions, long-period earthquakes, lahar events, and signals indicating emissions. Weather clouds and rain sometimes prevented visual observations of the volcano, especially during 8-9 May. Based on the Washington VAAC and occasional webcam images, ash plumes were visible during 4-8 and 10 May rising as high as 2 km above the summit and drifting mainly NW, W, and SW. Eruptions during midmorning and again around noon on 7 May produced ash plumes that rose 2.3 km and drifted WSW; higher plumes rose 5.4 km and drifted NW. Notable ashfall was reported in multiple places in the afternoon; in Guamote (40 km WNW), in Riobamba, and Alusí. A lava flow descended the SE flank. Minor amounts of ash fell in parts of the Guayas province in the morning of 8 May. The seismic network recorded lahar signals during 7-10 May.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
Report for Santa Maria
INSIVUMEH reported that during 4-11 May daily explosions at Santa María’s Santiaguito lava-dome complex generated ash plumes that rose as high as 1.1 km above the summit and drifted W, SW, and S. Collapses of blocky lava from Caliente dome sent avalanches down the SE, S, SW, and W flanks, sometimes reaching the base, and causing minor ashfall around the volcano. Ashfall was also reported in San Marcos (8 km SW) and Loma Linda Palajunoj (6 km WSW) during 5-6 and 10-11 May.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Semeru
PVMBG reported that Semeru continued to erupt during 4-11 May. Avalanches of material traveled 200-300 m SE down the Kobokan drainage on 6 May. Gray-and-white plumes rose 200-500 m above the summit and drifted S during 8-9 May. Avalanches of material traveled as far as 700 m down the Kobokan drainage. 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 Semisopochnoi
AVO lowered the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory for Semisopochnoi on 7 May, noting that no ash emissions had been observed nor explosions recorded since 26 April. Sulfur dioxide emissions were recorded on 1 and 5 May, signifying continued unrest. Steam plumes were visible rising from the N crater of Mt. Cerberus on 7 May.
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 30 April-7 May. 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 4-11 May. Weather conditions sometimes prevented visual observations of the volcano, though white fumarolic plumes were visible almost daily rising as high as 500 m above the summit and drifting in multiple directions. Daily avalanches descended 500-1,500 m down the E and SE flanks. At 1119 on 6 May an ash plume rose 2 km above the summit and drifted E. At 0908 and 1519 on 7 May ash plumes rose 3 km and drifted E. Ash plumes rose 1-2.8 km and drifted E, WNW, and W at 1044, 1656, and 1841 on 8 May; plumes were also seen on 9 May. At 0747 on 10 May an ash plume rose 2.5 km and drifted SW. Ash plumes on 11 May rose 700 m and drifted W at 0712, and rose 1.5 km and drifted E at 1428. 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 Soufriere St. Vincent
On 6 May government authorities lowered the Alert Level to Orange for Soufrière St. Vincent (often simply referred to as “La Soufriere”) based on recommendations from University of the West Indies Seismic Research Centre (UWI-SRC). The public was allowed to return to their homes in the Yellow and Orange zones, though access to the Red Zone remained restricted. UWI-SRC noted that over the previous few days continuing lahars had mobilized boulders 5 m in diameter and were steamy in areas where they contacted hot deposits. A small lahar signal was recorded at 0740 on 7 May. Sulfur dioxide emissions were measured from a boat near the W coast, yielding a flux of 208 tons per day on 9 May. Seismicity remained low through 11 May with only a few long-period earthquakes recorded by the seismic network.
Sources: University of the West Indies Seismic Research Centre (UWI-SRC), National Emergency Management Organisation (NEMO), Government of Saint Vincent and the Grenadines
Report for Suwanosejima
JMA reported that 35 explosions at Suwanosejima's Ontake Crater produced eruption plumes that rose as high as 2.4 km above the crater rim during 30 April-7 May. Large volcanic bombs were ejected 700 m from the crater. Crater incandescence was visible nightly. The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.
Source: Japan Meteorological Agency (JMA)