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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 26 April-2 May 2023
Name Location Eruption Start Date Report Status
Ambae Vanuatu New
Barren Island Andaman Islands (India) New
Bezymianny Central Kamchatka (Russia) 2016 Dec 5 New
Kanlaon Philippines New
Rincon de la Vieja Costa Rica 2021 Jun 28 New
Sheveluch Central Kamchatka (Russia) 1999 Aug 15 New
Aira Kyushu (Japan) 2017 Mar 25 Continuing
Cotopaxi Ecuador Continuing
Ebeko Paramushir Island (Russia) 2022 Jun 11 Continuing
Fuego South-Central Guatemala 2002 Jan 4 Continuing
Great Sitkin Andreanof Islands (USA) 2021 May 25 Continuing
Lewotolok Lembata Island 2020 Nov 27 Continuing
Merapi Central Java 2020 Dec 31 Continuing
Popocatepetl Mexico 2005 Jan 9 Continuing
Ruapehu North Island (New Zealand) Continuing
Sangay Ecuador 2019 Mar 26 Continuing
Santa Maria Southwestern Guatemala 1922 Jun 22 Continuing
Semeru Eastern Java 2017 Jun 6 Continuing
Semisopochnoi Aleutian Islands (USA) Continuing
Stromboli Aeolian Islands (Italy) 1934 Feb 2 Continuing
Suwanosejima Ryukyu Islands (Japan) 2004 Oct 23 Continuing
Yasur Vanuatu 1270 ± 110 years Continuing
All times are local unless otherwise stated.
Weekly Reports Archive

Since the Weekly Volcanic Activity Report began in November 2000, there have been 19,934 individual reports over 1,212 weeks (average of 16 per week) on 332 different volcanoes.

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Agung Cuicocha Iliwerung Llaima Popocatepetl Sumbing
Ahyi Cumbal Inielika Lokon-Empung Purace Sundoro
Aira Dabbahu Ioto Lonquimay Puyehue-Cordon Caulle Suretamatai
Akan Davidof Irazu Lopevi Rabaul Suwanosejima
Alaid Dempo Iya Machin Raikoke Taal
Alu-Dalafilla Descabezado Grande Izu-Torishima Makushin Ranakah Tair, Jebel at
Ambae Dieng Volcanic Complex Jackson Segment Maly Semyachik Raoul Island Takawangha
Ambang Dukono Kaba Manam Rasshua Talang
Ambrym East Epi Kadovar Manda Hararo Raung Tambora
Anatahan Ebeko Kaitoku Seamount Marapi Redoubt Tanaga
Aniakchak Ebulobo Kama'ehuakanaloa Maroa Reventador Tandikat-Singgalang
Antillanca Volcanic Complex Edgecumbe Kambalny Martin Reykjanes Tangkoko-Duasudara
Antuco Egon Kanaga Masaya Rincon de la Vieja Tangkuban Parahu
Apoyeque Ekarma Kanlaon Maule, Laguna del Rinjani Tara, Batu
Arenal Eldey Karangetang Mauna Loa Ritter Island Ta'u
Asamayama Erebus Karkar Mayon Rotorua Taupo
Askja Erta Ale Karthala McDonald Islands Ruang Telica
Asosan Etna Karymsky Melebingoy Ruapehu Tenerife
Atka Volcanic Complex Etorofu-Yakeyama [Grozny Group] Kasatochi Melimoyu Ruby Tengger Caldera
Augustine Eyjafjallajokull Katla Merapi Ruiz, Nevado del Three Sisters
Avachinsky Fagradalsfjall Katmai Midagahara Sabancaya Tinakula
Awu Fernandina Kavachi Misti, El Sakar Tofua
Axial Seamount Fogo Kelimutu Miyakejima Salak Tokachidake
Azul, Cerro Fonualei Kelud Momotombo San Cristobal Tolbachik
Azumayama Fournaise, Piton de la Kerinci Monowai San Miguel Toliman
Bagana Fourpeaked Ketoi Montagu Island San Vicente Tongariro
Balbi Fuego Kharimkotan Moyorodake [Medvezhia] Sangay Trident
Bamus Fujisan Kick 'em Jenny Mutnovsky Sangeang Api Tungurahua
Banda Api Fukutoku-Oka-no-Ba Kie Besi Myojinsho Santa Ana Turrialba
Bardarbunga Galeras Kikai Nabro Santa Maria Ubinas
Barren Island Galunggung Kilauea Negra, Sierra Sao Jorge Ugashik-Peulik
Batur Gamalama Kirishimayama Negro, Cerro Sarigan Ukinrek Maars
Bezymianny Gamkonora Kita-Ioto Nightingale Island Sarychev Peak Ulawun
Bogoslof Gareloi Kizimen Nishinoshima Saunders Unnamed
Brava Gaua Klyuchevskoy Nisyros Savo Unnamed
Bristol Island Gorely Kolokol Group Novarupta Semeru Veniaminof
Bulusan Great Sitkin Koryaksky NW Rota-1 Semisopochnoi Villarrica
Calbuco Grimsvotn Krakatau Nyamulagira Seulawah Agam Vulcano
Callaqui Guagua Pichincha Krummel-Garbuna-Welcker Nyiragongo Sheveluch West Mata
Cameroon Guallatiri Krysuvik-Trolladyngja Ofu-Olosega Shishaldin Westdahl
Campi Flegrei del Mar di Sicilia Guntur Kuchinoerabujima Okataina Simbo Whakaari/White Island
Cayambe Hachijojima Kurikomayama Okmok Sinabung Witori
Chachadake [Tiatia] Hakoneyama Kusatsu-Shiranesan Ontakesan Sinarka Wolf
Chaiten Heard Kverkfjoll Oraefajokull Siple Wrangell
Chiginagak Hekla La Palma Osorno Sirung Yakedake
Chikurachki Helgrindur Lamington Pacaya Slamet Yasur
Chiles-Cerro Negro Hierro Lamongan Pagan Snaefellsjokull Yufu-Tsurumi
Chillan, Nevados de Hokkaido-Komagatake Langila Palena Volcanic Group Soputan Zaozan [Zaosan]
Chirinkotan Home Reef Lanin Paluweh Sorikmarapi Zavodovski
Chirpoi Hood Lascar Panarea Sotara Zhupanovsky
Ciremai Huaynaputina Late Papandayan Soufriere Hills Zubair Group
Cleveland Hudson, Cerro Lateiki Pavlof Soufriere St. Vincent
Colima Huila, Nevado del Lengai, Ol Doinyo Pelee South Sarigan Seamount
Colo Hunga Tonga-Hunga Ha'apai Leroboleng Peuet Sague Spurr
Concepcion Ibu Lewotobi Pinatubo St. Helens
Copahue Ijen Lewotolok Planchon-Peteroa Stromboli
Cotopaxi Iliamna Little Sitkin Poas Sulu Range
 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 Ambae
On 27 April the Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that the cone in Ambae’s Lake Voui continued to produce emissions consisting of steam, volcanic gases, and ash. Volcanic earthquakes were recorded by the seismic network. Activity intensified during 5-7 April and was characterized by higher steam, gas, and ash plumes and nighttime incandescence from the growing cone. Lava flows from the vent traveled N into a small water lake, filling it in. 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.
Sources: Vanuatu Meteorology and Geohazards Department (VMGD), Wellington Volcanic Ash Advisory Center (VAAC)
Report for Barren Island
The Darwin VAAC reported that continuous ash plumes from Barren Island were identified in satellite images during 0620-1250 on 1 May rising to 4.6 km (15,000 ft) a.s.l. and drifting NW.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
Report for Bezymianny
KVERT reported that the ongoing eruption at Bezymianny was characterized by gas-and-steam emissions, occasional collapses at the lava dome, and hot avalanches during 20-27 April. A daily thermal anomaly was identified in satellite images. The Aviation Color Code remained at Yellow (the second lowest 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 Kanlaon
PHIVOLCS issued a special notice for Kanlaon at 0700 on 1 May, noting increased sulfur dioxide emissions. Real-time, continuous volcanic gas monitoring of thermal springs on the N flank detected sulfur dioxide for the first time beginning in April. On 30 April a Flyspec instrument measured an average of 1,099 tonnes per day of sulfur dioxide emissions at the summit crater, a value which was significantly higher than the average of 124 tonnes per day measured since March. During the month of April, the seismic network recorded 141 volcanic earthquakes, an average of five per day, at shallow depths less than 10 km in the N and W parts of the volcano. Ground deformation data from continuous GPS and electronic tilt data indicated short-term inflation of the lower and mid-flanks of the volcano since March. The Alert Level remained at 1 (on a scale of 0-5) and PHIVOLCS reminded the public to remain outside of the 4-km-radius Permanent Danger Zone.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
Report for Rincon de la Vieja
OVSICORI-UNA reported that phreatic eruptions continued to periodically occur at Rincón de la Vieja during 26 April-1 May. Near-continuous and intense tremor continued along with a few low-frequency, tornillo-type earthquakes and volcanic-tectonic earthquakes. Phreatic events at 0453, 0523, and 0545 on 26 April generated gas-and-steam plumes, and an event at 0528 on 27 April produced a gas-and-steam plume that rose 800 m above the crater rim. Several phreatic events occurred during 27-28 April and generated gas-and-steam emissions that generally rose no higher than 200 m above the crater rim. A small event at 1030 on 30 April produced a gas-and-steam plume that rose 500 m. A gas-and-steam plume from a moderate phreatic eruption at 1306 on 1 May rose 1 km above the crater rim and was seen by residents N of the volcano and in images from webcams located in Sensoria and Gavilan. A small event was recorded later that day at 2032.

Field observations found that the larger eruption on 21 April ejected tephra up to 3 km around the crater, mainly to the N and S. An analysis of ash deposits under a microscope revealed gray and dark metallic, sulfur-rich spheres characteristic of the hydrothermal system as well as juvenile volcanic glass. Ballistics up to 15 cm in diameter were found around the crater.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
Report for Sheveluch
KVERT reported that the ongoing eruption at Sheveluch was generally characterized by occasional explosions, continuing lava-dome growth, incandescence, and strong fumarolic activity during 20-27 April. Gas-and-steam emissions obscured the volcano during 20-23 April. A thermal anomaly was identified in satellite images during 24-27 April. A photograph taken on 29 April by the Kamchatka Volcanological Station showed a lava dome which was higher than the crater rim. 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.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Kamchatka Volcanological Station
Report for Aira
JMA reported ongoing eruptive activity at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) during 24 April-2 May, with crater incandescence visible nightly. Very small eruptive events occasionally occurred during the week. On 28 April sulfur dioxide emissions were somewhat high at 1,800 tons per day. An explosion at 0422 on 2 May ejected large blocks 500-700 m from the crater and generated an ash plume that rose 1.8 km above the crater rim and drifted SW. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from both craters.
Source: Japan Meteorological Agency (JMA)
Report for Cotopaxi
IG reported ongoing moderate eruptive activity at Cotopaxi during 26 April-2 May. Cloudy weather sometimes prevented webcam and satellite views, but emissions of steam-and-ash were visible on most days. On 26 April a gas plume with minor amounts of ash rose 500 m above the crater rim and drifted E. On 28 April an ash plume rose 800 m and drifted SE and W; ashfall was reported in the S part of Parque Nacional Cotopaxi. Gas-and-ash plumes rose 800 m and drifted W on 29 April, and two ash emissions rose 200-800 m and drifted SW and W on 30 April. At 0130 on 1 May the seismic network began recording a high-frequency signal that corresponded to the descent of a very small secondary lahar that remained within the bounds of Parque Nacional Cotopaxi. Gas-and-ash emissions rose 300 m and drifted W during 1-2 May. Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE) maintained the Alert Level at Yellow (the second lowest level on a four-color scale).
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE)
Report for Ebeko
KVERT reported that moderate activity at Ebeko was ongoing during 20-27 April and a thermal anomaly was identified in satellite images on 20 and 26 April. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) and satellite data explosions during 22 and 25-26 April generated ash plumes that rose as high as 3.5 km (11,500 ft) a.s.l. and drifted E. 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 Fuego
INSIVUMEH reported that a range of 5-14 weak and moderate explosions per hour were recorded at Fuego during 26 April-2 May. The explosions generated ash plumes, weak to moderate rumbling sounds, and shockwaves that vibrated the roofs and windows of nearby houses. Ash plumes rose 1.1 km above the crater and sometimes dispersed as far as 15 km S, SW, SE, and W. Ash fall was reported in Panimaché I and II (8 km SW), Morelia (9 km SW), Santa Sofía (12 km SW), El Porvenir (11 km SW), Finca La Asunción, La Rochela (8 km SSW), Finca Ceilán (9 km S), and San Andres Osuna. Incandescent material was ejected as high as 350 m above the crater almost daily. Weak and moderate avalanches descended multiple drainages including the Seca (W), Ceniza (SSW), Taniluyá (SW), Trinidad (S), Las Lajas (SE), Santa Teresa (ESE), and Honda (SE); sometimes reaching the edges of vegetation. In the evening on 27 April a weak-to-moderate lahar descended the Ceniza, a tributary of the Achiguate River, and consisted of fine-grain, hot material, branches, tree trunks, and blocks that ranged from 30 cm to 1.5 m in diameter.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Great Sitkin
AVO reported that lava continued to slowly erupt at the summit of Great Sitkin during 26 April-2 May. Weather clouds obscured satellite and webcam views during most of the week. Seismicity was low, and during 27-28 April only a few small events were detected. Satellite data last acquired up to 24 April showed that the thick lava continued to expand toward the E and remained confined to the summit crater. The Volcano Alert Level remained at Watch (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Lewotolok
PVMBG reported that the eruption at Lewotolok was ongoing during 26 April-2 May. Almost daily white-and-gray plumes rose as high as 500 m above the summit and drifted NW, W, and SW. White gas-and-steam plumes rose 300 m and drifted SW on 28 April. Crater incandescence was visible in webcam images posted with the 27 April report. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 2 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 eruption at Merapi (on Java) continued during 21-27 April and seismicity remained at elevated levels. The SW lava dome produced 148 lava avalanches that traveled as far as 2 km down the SW flank (upstream in the Bebeng and Boyong drainages). Morphological changes to the SW lava dome were evident in webcam images due to continuing collapses of material. 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 Popocatepetl
CENAPRED reported that there were 65-288 daily steam-and-gas emissions, sometimes containing ash, and daily explosions at Popocatépetl during 26 April-2 May. Ash-and-gas plumes drifted ENE. On most days webcam images showed nighttime incandescence in the crater and from material that had been deposited on the upper flanks. A moderate explosion at 0109 on 26 April ejected material that landed on the N flank as far as 1 km from the crater rim. A minor explosion was recorded later that day at 1817. A moderate explosion at 0116 on 27 April ejected incandescent material onto the upper flanks. Another moderate explosion was recorded at 1147 and minor explosions were recorded at 0348, 0606, 0857, and 1059. Minor explosions continued to be detected during the rest of the week: at 0857 and 1750 on 28 April, 0150 and 2350 on 29 April, at 2205, 2220, 2256, and 2345 on 30 April, and at 0000, 0130, 0356, 0454, and 0506 on 1 May. A moderate explosion occurred at 1249 on 30 April. On 2 May minor explosions occurred at 0335 and 0942. According to the Washington VAAC ash plumes were identified in satellite images daily rising 5.8-7.3 km (19,000-24,000 ft) a.s.l. (0.4-1.9 km above the crater rim) and drifting NE, E, and SE. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale).
Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), Washington Volcanic Ash Advisory Center (VAAC)
Report for Ruapehu
On 3 May GeoNet reported that temperatures in Ruapehu’s cater lake had declined from 32 to 21 degrees Celsius since January, and other monitoring parameters indicated that volcanic unrest remained low. Weak volcanic tremor persisted and very few earthquakes were located beneath the volcano. Gas emissions were at low-to-moderate levels during the previous three months, and only minor changes to the lake water chemistry were identified over the past several months and most recently on 6 April. The Volcanic Alert Level remained at 1 (on a scale from 0-5) and the Aviation Color Code remained at Green (the lowest level on a four-color scale).
Source: GeoNet
Report for Sangay
IG reported a high level of activity at Sangay during 25 April-2 May. Gas, steam, and ash plumes were occasionally observed in IG webcam images or described in Washington VAAC volcanic activity notifications, though weather clouds prevented observations on most days. On 25 April an ash-and-gas plume rose as high as 6 km above the crater rim and drifted SW. That same day notifications issued by the Washington VAAC indicated that ash plumes rose to 4.7 km (22,000 ft) a.s.l. (1.4 km above the crater rim) and drifted E, SE, SW, and W. IG noted that minor amounts of ash fell in the Province of Chimborazo in the Matriz and Juan de Velasco parishes, and in the Guamote canton. The VAAC reported that ash plumes rose as high as 1.4 km above the crater rim and drifted in multiple directions during 26-27 and 29 April. IG noted that a minor ash plume was visible in satellite images drifting W on 28 April. On 1 May an ash plume rose 1 km above the crater rim and drifted W. Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE) maintained the Alert Level at Yellow (the second lowest level on a four-color scale).
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE)
Report for Santa Maria
INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 26 April-2 May. Effusion from the Caliente dome complex fed lava flows that descended the San Isidro and Zanjón Seco drainages on the W and SW flanks; the main lava flow was 4.3 km long and remained active. Daily weak-to-moderate explosions generated ash-and-steam plumes that rose as high as 1 km above the dome and drifted W and SW. The explosions were also accompanied by block-and-ash flows that descended multiple flanks of the dome. Avalanches of material were also generated from the lava-flow front and margins. During 28-29 April quiet rumbling sounds were barely heard on nearby farms. Incandescence from the dome and the lava flows was visible nightly. On 28 April a lahar descended the Cabello de Angel River, a tributary of the Nimá I and Samalá rivers, on the E flank and was registered by the nearby seismic stations. The lahar consisted of volcanic material, water, volcanic blocks up to 1 m in diameter, and tree trunks and branches. On 30 April at 0920 a moderate explosion generated a pyroclastic flow that traveled 5 km SW and produced an ash cloud that rose 100 m along the flow. Seismic data confirmed that the event lasted 40 minutes.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
Report for Semeru
PVMBG reported that the eruption at Semeru continued during 26 April-2 May and frequent Volcano Observatory Notices for Aviation (VONAs) describing ash emissions were issued through the week. On 28 April at 0739, 0822, and 2035 dense white-and-gray or gray-to-brown ash plumes rose 500-1,000 m above the summit and drifted S and SW. On 29 April at 0551 and 0734 dense white-and-gray ash plumes rose 800-1,000 m and drifted S. At 0624 and 0738 on 30 April white-and-gray ash plumes of variable densities rose 500-800 m and drifted NE. At 0611 on 1 May a dense white-and-gray ash plume rose 700 m and drifted S and SW, and at 0705 on 2 May a dense white-and-gray ash plume rose 500 m and drifted N. 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 in all directions, 13 km from the summit to the SE, 100 m from the banks of the Kobokan drainage as far as 17 km from the summit, and to avoid 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 unrest continued at Semisopochnoi during 26 April-2 May. Seismicity was at low levels, and a few small local earthquakes were recorded during 28-29 April. Daily minor steam emissions were seen rising from Mount Young, though cloudy weather sometimes prevented webcam and satellite views. Ash deposits near the crater rim were visible during 27-28 April, though it was unclear if they were recent. The Volcano Alert Level remained at Watch (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest color on a four-color scale).
Source: US Geological Survey Alaska Volcano Observatory (AVO)
Report for Stromboli
INGV reported ongoing Strombolian activity at Stromboli during 24-30 April. Activity was centered at two vents (one each at craters N1 and N2) in Area N, within the upper part of the Sciara del Fuoco, and from three vents in the Area C-S (South-Central Crater area) in the crater terrace area. Explosions at the N1 and N2 craters in Area N were low to medium intensity and ejected coarse material (bombs and lapilli), sometimes mixed with ash, 80-150 m high at a rate of 3-8 explosions per hour. Explosions at the three vents in sector S2 (Area C-S) ejected ash sometimes mixed with coarse material at an average rate of 4-7 explosions per hour. Sectors C and S1 in Area C-S did not show significant activity. Although thermal activity was generally low and the summit was often clouded by weather, a thermal anomaly was detected at 0150 on 29 April.
Source: Sezione di Catania - Osservatorio Etneo (INGV)
Report for Suwanosejima
JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 24 April-1 May. No explosions were recorded, but eruptive activity produced periodic ash plumes, and during 28 April-1 May blocks were ejected as far as 200 m from the vent. On 27 April at 0838 and 0943 ash-and-gas plumes rose 1-1.1 km above the crater rim and drifted W, and on 28 April at 0643 an ash-and-gas plume rose 1.5 km and drifted NW. 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 Yasur
On 27 April the 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). Recent observations confirmed that low-to-moderate explosions continued, ejecting bombs that landed back into the crater and producing gas-and-ash emissions. The larger explosions occasionally ejected material outside of 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 Geohazards Department (VMGD)