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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 11 May-17 May 2022
Name Location Eruption Start Date Report Status
Awu Sangihe Islands New
Cleveland Chuginadak Island (USA) New
Krakatau Sunda Strait 2021 May 25 New
Reykjanes Reykjanes Peninsula New
Aira Kyushu (Japan) 2017 Mar 25 Continuing
Etna Sicily (Italy) 2013 Sep 3 Continuing
Fuego South-Central Guatemala 2002 Jan 4 Continuing
Great Sitkin Andreanof Islands (USA) 2021 May 25 Continuing
Ibu Halmahera 2008 Apr 5 Continuing
Karymsky Eastern Kamchatka (Russia) 2020 Apr 1 Continuing
Katmai Alaska Continuing
Kilauea Hawaiian Islands (USA) 2021 Sep 29 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
Reventador Ecuador 2008 Jul 27 Continuing
Rincon de la Vieja Costa Rica 2021 Jun 28 Continuing
Ruapehu North Island (New Zealand) Continuing
Sangay Ecuador 2019 Mar 26 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
Sinabung Northwestern Sumatra Continuing
Stromboli Aeolian Islands (Italy) 1934 Feb 2 Continuing
Suwanosejima Ryukyu Islands (Japan) 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 18,190 individual reports over 1,134 weeks (average of 16 per week) on 327 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 Tungurahua
Bardarbunga Galeras Kie Besi Nabro Santa Ana Turrialba
Barren Island Galunggung Kikai Negra, Sierra Santa Maria Ubinas
Batur Gamalama Kilauea Negro, Cerro Sao Jorge Ugashik-Peulik
Bezymianny Gamkonora Kirishimayama Nightingale Island Sarigan Ukinrek Maars
Bogoslof Gareloi Kita-Ioto Nishinoshima Sarychev Peak Ulawun
Brava Gaua Kizimen Nisyros Saunders Unnamed
Bristol Island Gorely Klyuchevskoy Novarupta Savo Unnamed
Bulusan Great Sitkin Kolokol Group NW Rota-1 Semeru Veniaminof
Calbuco Grimsvotn Koryaksky Nyamulagira Semisopochnoi Villarrica
Callaqui Guagua Pichincha Krakatau Nyiragongo Seulawah Agam Vulcano
Cameroon Guallatiri Krummel-Garbuna-Welcker Ofu-Olosega Sheveluch West Mata
Campi Flegrei del Mar di Sicilia Guntur Krysuvik-Trolladyngja Okataina Shishaldin Westdahl
Cayambe Hachijojima Kuchinoerabujima Okmok Simbo Whakaari/White Island
Chachadake [Tiatia] Hakoneyama Kurikomayama Ontakesan Sinabung Witori
Chaiten Heard Kusatsu-Shiranesan Oraefajokull Sinarka Wolf
Chiginagak Hekla Kverkfjoll Osorno Siple Yakedake
Chikurachki Helgrindur La Palma Pacaya Sirung Yasur
Chiles-Cerro Negro Hierro Lamington Pagan Slamet Yufu-Tsurumi
Chillan, Nevados de Hokkaido-Komagatake Lamongan Palena Volcanic Group Snaefellsjokull Zaozan [Zaosan]
Chirinkotan Home Reef Langila Paluweh Soputan Zavodovski
Chirpoi Hood Lanin Panarea Sorikmarapi Zhupanovsky
Ciremai Huaynaputina Lascar Papandayan Sotara Zubair Group
Cleveland Hudson, Cerro Lateiki Parker Soufriere Hills
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
 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 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 Awu
PVMBG had raised the Alert Level for Awu to 2 (on a scale of 1-4) on 12 December 2021 because of a notable increase in the number of both shallow and deep volcanic earthquakes. Since then the number of shallow and deep volcanic earthquakes averaged 8 and 5 events per day, respectively. Gas emissions had not been visible, though weather conditions sometimes prevented views of the volcano. Another significant seismic increase was recorded on 9 May, with 88 shallow events and 147 deep events, and then again the following day with 90 shallow events and 203 deep events. At 1500 on 11 May a white emission was observed rising about 30 m above the crater rim. The Alert Level was raised to 3, and the public was warned to stay at least 3.5 km away from the summit crater.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Cleveland
AVO reported that during 11-17 May elevated surface temperatures over Cleveland were identified in satellite images. No significant seismic or infrasound activity was detected. A continuous sulfur dioxide plume drifted 500 km during 15-16 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 during 10-12 May ash plumes from Anak Krakatau rose to 2.4 km (8,000 ft) a.s.l. and drifted E, N, NW, and W based on satellite images and weather models. On 13 May satellite images showed a narrow ash plume drifting SE and E at an altitude of 2.4 km. Dense steam plume with minor ash content rose to 2.4 km and drifted NE, N, NW, and W during 14-16 May.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Report for Reykjanes
The National Commissioner of the Icelandic Police declared a level of “uncertainty” for the Reykjanes Peninsula on 15 May, noting that the declaration meant that responders and agencies were to review their preparedness plans in response to recent increases in seismicity and deformation. IMO raised the Aviation Color Code for Reykjanes to Yellow on 16 May, stating that more than 3,000 earthquakes had been detected near Eldvörp in the Reykjanes/Svartsengi volcanic system during the past week. Nine earthquakes above M 3 and two earthquakes above M 4 were recorded during 15-16 May; the largest event was a M 4.3 which was recorded at 1738 on 15 May. The earthquakes were located at depths of 4-6 km. GPS and InSAR data detected inflation W of Thorbjörn during the previous two weeks, likely caused by a magmatic intrusion at 4-5 km depth.
Sources: Icelandic Meteorological Office (IMO), Almannavarnadeild ríkislögreglustjóra (National Commissioner of the Icelandic Police and Department of Civil Protection and Emergency Management)
Report for Aira
JMA reported that a very small eruptive event was recorded at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) during 9-13 May. An eruptive event at 1141 on 15 May generated a plume that rose 1.2 km above the crater rim. 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 Etna
INGV reported that at around 1900 on 12 May new vents opened along the N flank of Etna’s Southeast Crater (SEC) and produced ash emissions that rose to 3.5 km (11,500 ft) a.s.l. and drifted SW. Lava flowed from the vents and traveled to the N base of the crater. Lava effusion continued over the next several days, and by 17 May the flow had descended ENE into Valle del Leone, reaching 2,300-2,400 m elevation. Discontinuous Strombolian activity of variable intensities occurred at SEC; during more intense phases ash emissions were visible, though the plumes dissipated rapidly.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Fuego
INSIVUMEH reported that 2-9 explosions per hour were recorded at Fuego during 10-17 May, generating ash plumes that rose as high as 1.1 km above the crater rim. The ash plumes drifted 10-15 km E, SE, S, and SW causing daily ashfall in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), Finca Palo Verde, Finca la Asunción, El Zapote (10 km S), Ceylon, Yucales (12 km SW), El Porvenir (8 km ENE), Alotenángo (8 km ENE), San Miguel Dueñas (10 km NE), San Sebastián, and La Rochela. Daily shock waves rattled structures in communities around the volcano and occasional rumbling was heard. Block avalanches descended the 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. Daily explosions ejected incandescent material 100-350 m above the summit.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Great Sitkin
AVO reported that minor advancement of the lava flows at Great Sitkin indicated continuing slow lava effusion during 10-17 May. Daily elevated surface temperatures were identified in satellite data. 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 11-17 May. Daily gray-and-white ash plumes of variable densities generally rose 200-800 m above the summit and drifted mainly W and N. Eruptive events at 0903 and 1807 on 14 May and at 1759 on 15 May produced ash plumes that rose 0.8-1 km above the summit and drifted W and SW. At 1646 on 16 May dense gray ash plumes rose around 2.5 km and drifted W. 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 a thermal anomaly over Karymsky was visible in satellite images during 6-13 May. Explosions on 12 May generated ash plumes that rose as high as 6 km (19,700 ft) a.s.l. by 1120 local time and drifted about 30 km NW. Explosions on 14 May produced ash plumes that rose to 5.7 km (18,700 ft) a.s.l. by 0940 local time and drifted 28 km NE. 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 13 May strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes blew unconsolidated ash SE towards Kodiak Island at an altitude up to 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 10-17 May, entering the active lava lake and flowing onto the crater floor. By 10 May the total volume of erupted lava was an estimated 77 million cubic meters, and the lake which had risen a total of 106 m since 29 September 2021. 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 NE and NW margins of the lake during 10-11 May, and more notably from the E margins the rest of the week. 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 10-17 May. An increase in gas emissions along with continuing ash emissions was observed on 14 and 17 May. The ash emissions rose to 1-2.4 km above the summit and drifted W, N, and NE. 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 13-16 May ash plumes from Manam rose to 2.4-3.7 km (8,000-12,000 ft) a.s.l. and drifted NE, SW, and W based on satellite images and weather models.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Report for Merapi
BPPTKG reported no significant morphological changes at Merapi’s summit lava dome during 6-12 May, though the height of the dome below the SW rim had increased by around 2 m. As many as 92 lava avalanches traveled a maximum of 2 km, mostly down the Bebeng drainage on the SW flank. Two 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 10-17 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 Reventador
IG reported that a high level of activity continued at Reventador during 10-17 May, though cloudy weather conditions sometimes prevented visual observations, particularly during 14-15 May. Gas-and-ash plumes, often observed multiple times a day as reported by the Washington VAAC, rose as high as 1 km above the summit and drifted mainly NW and W. Incandescence from the crater and incandescent blocks rolling 600 m down the flanks was visible during 10-13 May. During the morning of 17 May a new lava flow descended the NE flank.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
Report for Rincon de la Vieja
On 13 May OVSICORI-UNA reported that 23 small phreatic explosions at Rincón de la Vieja were recorded during the previous week. Eruptive events at 2328 on 10 May and 0700 on 11 May were recorded by the seismic network through darkness and cloudy weather conditions prevented visual confirmation. Tremor levels decreased significantly on 12 May.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
Report for Ruapehu
On 17 May GeoNet reported that elevated unrest at Ruapehu continued, though at reduced levels. During the previous two weeks the level of volcanic tremor declined from strong to moderate. The lake water temperature decreased from a peak of 41 degrees Celsius on 8 May to 37 degrees Celsius. 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 at 179 and 1,658 tonnes per day, respectively. Lake upwelling over the northern vent area was also visible during the overflight. 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 Sangay
IG reported a high level of activity at Sangay during 10-17 May. Weather clouds and rain often prevented visual and webcam observations of the volcano, though almost daily ash-and-gas plumes were identified in satellite images by the Washington VAAC; plumes rose as high as 1.5 km above the volcano and drifted W. Almost daily, multiple daily thermal anomalies over the volcano were visible in satellite data. The seismic network detected signals indicating lahars or possible lahars during 13-17 May.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
Report for Santa Maria
INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 10-17 May. Incandescence from Caliente crater and the lava flows on the W and SW flanks was visible nightly and during some early mornings. 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.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Semeru
PVMBG reported that the eruption at Semeru continued during 11-17 May. An eruptive event at 0608 on 14 May generated an ash plume that rose 200 m and drifted N. Another event recorded at 0634 on 17 May produced an ash plume that rose 300 m and drifted SW. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 500 m away from Kobokan drainages within 17 km of the summit, along with other drainages originating on Semeru, including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Semisopochnoi
AVO reported that low-level eruptive activity at Semisopochnoi's North Cerberus cone continued during 10-17 May. Seismicity continued to be elevated with intermittent tremor detected by the seismic network. Several daily explosions were recorded in infrasound and seismic data. Daily low-level ash emissions were visible in clear satellite images and webcam views. 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 6-13 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 Sinabung
PVMBG lowered the Alert Level for Sinabung to 2 (on a scale of 1-4) on 11 May, noting that data showed stability at the volcano. During 1 January-17 May gas emissions were frequently visible and detected by instruments; daily averages of sulfur dioxide emissions from passive degassing were below 250 tons per day, though a high value of about 4,000 tons per day was recorded in January, and white plumes of varying densities rose as high as 500 m above the summit. During the previous four months deformation data showed a downward trend and indicated deflation, and the number of deep and shallow volcanic earthquakes signals generally declined. Growth of the SE part of the lava dome continued at a low rate as indicated by low numbers of earthquake signals caused by fluid movement. Avalanches of material were indicated by seismic signals though not visually confirmed. The public was warned to stay at least 3 km away from the summit and 4.5 km on the SE flank.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Report for Stromboli
INGV reported that during 9-15 May activity at Stromboli was characterized by ongoing explosions from three vents in Area N (North Crater area) and two vents in Area C-S (South-Central Crater area). During 9-13 May explosions from Area N vents (N1 and N2) averaged 2-4 events per hour; explosions from the N1 vent ejected lapilli and bombs mixed with ash 80-150 m high and those at two N2 vents ejected material less than 80 m high. No explosions occurred at the S1 and C vents in Area C-S; low- to medium-intensity explosions at the two S2 vents occurred at a rate of 0-5 per hour and ejected coarse material 80-150 m high.

A sequence of six major explosions occurred at S1 and S2 in Area C-S during 1643-1647 on 13 May. The first, and most energetic, occurred at 1643 and ejected an abundant amount of coarse material 300 m high. The material fell in areas to the E and SE, and at Pizzo Sopra la Fossa (an area atop the volcano about 100 m above the crater terrace). The second explosion was lower in intensity but also ejected coarse material. The third through the sixth explosion all ejected ash. Deposits from the explosions seen during a field visit the next day were found as far at 450 m elevation, and impacts from ballistics were found along the switchbacks up the Liscione between 700 and 830 m elevation. Decimeter to meter-sized bombs were observed near 850 m elevation. Elongated tephra, centimeter to decimeter in size, was seen near Pizzo Sopra la Fossa. The CS vent area had deepened and the vents were elongated towards the central part. After the sequence of explosions on 13 May, through 15 May, explosive activity at N1, N2, and Area C-S was low.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Suwanosejima
JMA reported that eruptive activity continued to be recorded at Suwanosejima's Ontake Crater during 9-16 May. Eruption plumes rose as high as 1 km above the crater rim and material was ejected 400 m above the vent; no explosions were recorded. Ash fell in Toshima village (3.5 km SSW) during 13-16 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)