Smithsonian / USGS Weekly Volcanic Activity Report

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 3 May-9 May 2023
Name	Location	Eruption Start Date	Report Status
Bulusan	Luzon (Philippines)	—	New
Fuego	South-Central Guatemala	2002 Jan 4	New
Gamalama	Halmahera	—	New
Kadovar	Northeast of New Guinea	—	New
Kanlaon	Philippines	—	New
Katla	Iceland	—	New
Aira	Kyushu (Japan)	2017 Mar 25	Continuing
Cotopaxi	Ecuador	—	Continuing
Ebeko	Paramushir Island (Russia)	2022 Jun 11	Continuing
Etna	Sicily (Italy)	2022 Nov 27	Continuing
Great Sitkin	Andreanof Islands (USA)	2021 May 25	Continuing
Ibu	Halmahera	2008 Apr 5	Continuing
Lewotolok	Lembata Island	2020 Nov 27	Continuing
Merapi	Central Java	2020 Dec 31	Continuing
Raung	Eastern Java	—	Continuing
Rincon de la Vieja	Costa Rica	2021 Jun 28	Continuing
Sabancaya	Peru	2016 Nov 6	Continuing
Santa Maria	Southwestern Guatemala	1922 Jun 22	Continuing
Semeru	Eastern Java	2017 Jun 6	Continuing
Semisopochnoi	Aleutian Islands (USA)	—	Continuing
Sheveluch	Central Kamchatka (Russia)	1999 Aug 15	Continuing
Suwanosejima	Ryukyu Islands (Japan)	2004 Oct 23	Continuing

All times are local unless otherwise stated.

Bulusan | 3 May-9 May 2023 | New Activity / Unrest Cite this Report

Bulusan
Luzon (Philippines)

PHIVOLCS reported that during 7-9 May the seismic network at Bulusan recorded a total of 17 volcanic earthquakes at depths of 0-5.2 km beneath the E flank. Six of the earthquakes were tornillo-type events associated with gas movement and the other 11 events were volcano-tectonic earthquakes associated with rock fracturing. Diffuse white steam plumes rose from the active vents in the summit crater. The Alert Level was lowered to 0 (the lowest level on a scale of 0-5) on 18 January and remained unchanged. PHIVOLCS reminded the public not to enter the 4-km-radius Permanent Danger Zone (PDZ).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

Fuego | 3 May-9 May 2023 | New Activity / Unrest Cite this Report

Fuego
South-Central Guatemala

INSIVUMEH reported that activity at Fuego during 2-9 May included intense explosions, dense ash emissions, lava effusion, pyroclastic flows, and lahars. During 1-3 May there were 5-8 weak explosions per hour generating dense ash plumes that rose more than 1 km above the summit and drifted to 10-15 km W, SW, and S. Explosions were accompanied by rumbling sounds and shockwaves that vibrated nearby houses. During the morning and night incandescent material was visible 100-200 m above the crater. Avalanches descended the Ceniza (SSW) and Las Lajas (SE) drainages, sometimes reaching vegetated areas. Ashfall was reported in areas downwind including Panimache I and II (8 km SW), Morelia (9 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Finca Palo Verde, Sangre de Cristo (8 km WSW), and Yepocapa (8 km N). In the early afternoon (around 1500) on 2 May lahars descended the Las Lajas and El Jute (ESE) drainages, carrying branches, tree trunks, and blocks 30 cm to 1.5 m in diameter; about 30 minutes later similar lahars descended the Ceniza drainage. At 1618 a weak-to-moderate pyroclastic flow traveled down the Ceniza and an associated ash plume drifted W and SW. Within 30 minutes after the pyroclastic flow a lahar descended the Seca (W), carrying tree trunks and branches, and blocks up to 1.5 m in diameter.

Activity intensified at around 0200 on 4 May with a new effusive phase; by 0510 a lava flow was traveling down the Ceniza drainage, incandescent material rose above the summit, avalanches were continuous, and ash-and-gas plumes drifted SW. At around 0700 weak-to-moderate pyroclastic flows descended the Ceniza and within 1.5 hours pyroclastic flows also descended the Las Lajas. Ashfall was reported on W-flank farms and communities including Finca La Asunción, La Rochela, Panimaché I and II, Morelia, Santa Sofía, as well as others at a greater distance such as San Rafael Sumatán (19 km WSW) and San Pedro Yepocapa. By 1000 moderate-to-strong pyroclastic flows were descending the W-flank Seca and Santa Teresa ravines. Loud rumbling sounds and shock waves were reported by local residents. Ashfall continued in communities near the Ceniza and Las Lajas ravines. Ash plumes rose 2.2 km above summit and drifted more than 50 km W and SW.

Activity continued at a high level and as of a special report posted at 1235 ash plumes were still rising more than 2.2 m above the summit. Pyroclastic flows were continuing and had traveled 5-7 km down the Ceniza, Las Lajas, Seca and Santa Teresa (W) drainages; the most intense pyroclastic flow had descended the Ceniza drainage minutes earlier. The ash plumes were identified in satellite images drifting more than 100 km W and SW. Significant ashfall continued in communities downwind and minor ashfall was reported in several municipalities of the department of Suchitepéquez.

The last pyroclastic flow descended the Ceniza at 1530. Avalanches continued to be seen and heard descending multiple flanks. Ash deposits up to 2 mm thick were noted on crops, houses, and streets. Activity began to wane at about 1800, though explosions continued to produce ash plumes that rose 1.2 km above the summit. The leading edge of the ash plume was 200 km W and SW of the volcano. According to CONRED, about 1,200 residents were preemptively evacuated from their homes in San Pedro Yepocapa, Chimaltenango (21 km NNE), Panimaché I and II, El Porvenir, and Morelia. According to news articles, a section of the RN-14 highway was closed from kilometer 84 of San Juan Alotenango, Sacatepequez (9 km ENE) to kilometer 95 in Escuintla due to the pyroclastic flows. An estimated 130,000 people lived within areas exposed to ashfall.

Activity during the morning of 5 May was characterized by some weak-to-moderate explosions, ash plumes that rose 850 m above the summit, crater incandescence, and ash in the air in communities around the Ceniza, Seca, and Las Lajas drainages. Ashfall continued to impact agriculture and infrastructure in Panimaché I, Morelia, Santa Sofía, La Rochela, Los Yucales, El Porvenir, Ceylon, Finca Asunción (12 km SW), Yepocapa, Santa Lucía Cotzumalguapa (22 km SW), Siquinalá (21 km SSW), and other nearby communities. By 1230 data from seismic and infrasound monitoring networks, webcam images, satellite data, and reports from observers in the field all indicated that activity had returned to normal levels. Weak explosions at a rate of 5-6 per hour produced minor ash plumes that rose as high as 850 m and drifted 30 km W. On 6 May weak explosion generated ash plumes that rose 750 m and drifted 10 km W and SW. The lava flow was no longer incandescent. According to a news report, residents returned to their communities that same day. During 7-9 May weak explosions continued to produce ash plumes that rose as high as 750 m above the summit and drifted W and SW. Minor avalanches descended the Ceniza and crater incandescence was occasionally observed.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Coordinadora Nacional para la Reducción de Desastres (CONRED), Prensa Libre, Prensa Libre

Gamalama | 3 May-9 May 2023 | New Activity / Unrest Cite this Report

Gamalama
Halmahera

PVMBG reported that the number of deep volcanic earthquakes at Gamalama increased during 1-3 May. The seismic network recorded 11 deep volcanic earthquakes on 1 May and 14 on 2 May. During 0000-0900 on 3 May the network recorded five deep volcanic earthquakes, one shallow volcanic earthquake, five events indicating emissions, and one low-frequency earthquake. Diffuse white gas-and-steam plumes rose as high as 100 m; typically, these emissions rose as high as 300 m. PVMBG noted that the most likely hazard would be a phreatic event that could ejected material within the 1.5-km radius, though ash may be carried farther. The Alert Level remained at 2 (on a scale of 1-4); visitors and residents were warned not to approach the crater within a 1.5-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Kadovar | 3 May-9 May 2023 | New Activity / Unrest Cite this Report

Kadovar
Northeast of New Guinea

Based on satellite and wind model data, the Darwin VAAC reported that at 2040 on 6 May a discrete ash plume from Kadovar rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted W. The plume had dissipated by 2300.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Kanlaon | 3 May-9 May 2023 | New Activity / Unrest Cite this Report

Kanlaon
Philippines

PHIVOLCS issued a special notice for Kanlaon at 2030 on 4 May, noting increased seismicity and ground deformation, and ongoing elevated sulfur dioxide emissions. 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, though during the second week of April inflation was pronounced at the SE mid-flank. Real-time, continuous gas monitoring of thermal springs on the N flank detected sulfur dioxide for the first time beginning in April. Sulfur dioxide emissions at the summit crater averaged 632 tonnes per day on 1 May, lower than the average of 1,099 tonnes per day measured the day before, but higher than the average of 124 tonnes per day emitted since March. The seismic network detected 20 shallow volcanic earthquakes (M 1.2-2.4) beneath the summit crater between 2225 on 3 May until 1600 on 4 May. 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)

Katla | 3 May-9 May 2023 | New Activity / Unrest Cite this Report

Katla
Iceland

Iceland Met Office (IMO) reported that an intense seismic swarm began at Katla at 0941 on 4 May with three earthquakes larger than M 4 occurring beneath the caldera within about 10 minutes. The Aviation Color Code was raised to Yellow, the second lowest level on a four-color scale. According to a news article the three largest events were magnitudes 4.8, 4.7, and 4.5, adjusted from previous estimates of 4.5, 4.3, and 4.2. The larger earthquakes were felt in Thórsmörk and by residents in areas S of Mýrdalsjökull glacier (the glacier that covers Katla). The intensity of the events decreased after noon, though smaller earthquakes continued. Seismicity had decreased significantly by the next day with only five events recorded during 0000-0915 on 5 May. In an update posted at 1140 the activity was described as normal, and the Aviation Color Code was lowered to Green. More than 40 earthquakes had been recorded during the previous day and no other data indicated significant changes or anomalies. It was noted that the magnitudes were unusually large and similar to events that last occurred in 2016.

Sources: Icelandic Meteorological Office (IMO), Iceland Monitor

Aira | 3 May-9 May 2023 | Continuing ActivityCite this Report

Aira
Kyushu (Japan)

JMA reported that Minamidake Crater and Showa Crater (Aira Caldera’s Sakurajima volcano) remained active during 1-8 May. Crater incandescence was observed nightly at Minamidake Crater. Three explosions at Minamidake during 2-3 May produced small shock waves and ash plumes. The explosion at 0422 on 2 May generated an ash plume that rose 1.8 km above the crater rim and drifted SW, and ejected blocks 500-700 m from the vent. The explosion at 0241 on 3 May produced an ash plume that rose 800 m and ejected blocks to 500-700 m from the vent. Later that morning, at 1025, an explosion produced an ash plume that rose 500 m and drifted W. An ash plume from an eruptive event at 2337 on 7 May rose 1 km. At Showa Crater very small eruptive events were recorded during 1-5 May, and three eruptive events on 8 May produced ash plumes that rose as high as 1.2 km above the crater rim and drifted S and 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)

Cotopaxi | 3 May-9 May 2023 | Continuing ActivityCite this Report

Cotopaxi
Ecuador

IG reported that moderate eruptive activity continued at Cotopaxi during 2-9 May. Seismic activity was largely dominated by long-period earthquakes, tremors indicating emissions, and a few volcano-tectonic earthquakes. Emissions of steam, gas, and variable amounts of ash were observed daily. During 2-3 May minor ash plumes rose less than 200 m above the crater rim and drifted W. On 4 May ash plumes rose as high as 1.5 km above the crater rim and drifted SW and NW, drifting as far as the province of Manabí. On 5 May several emissions with low ash content rose as high as 300 m and drifted SW. On 7 May ash plumes rose as high as 1.1 km above the crater rim and drifted W and SW, causing minor ashfall in areas downwind including Mulaló. On 8 May a seismic station recorded a small secondary lahar. Several steam-and-gas emissions were visible during 8-9 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)

Ebeko | 3 May-9 May 2023 | Continuing ActivityCite this Report

Ebeko
Paramushir Island (Russia)

KVERT reported that moderate activity at Ebeko was ongoing during 27 April-4 May. A thermal anomaly was identified in satellite images on 3 May. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 3-4 May generated ash plumes that rose as high as 4 km (13,100 ft) a.s.l. and drifted SW and 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)

Etna | 3 May-9 May 2023 | Continuing ActivityCite this Report

Etna
Sicily (Italy)

INGV reported that a sudden explosion at Etna’s SE Crater occurred at 2325 on 6 May and produced a diffuse ash emission that rapidly dispersed around the crater area. The Aviation Color Code was raised to Yellow at 2358 and then lowered back to Green at 1148 on 7 May. Neither seismic nor infrasound data recorded changes associated with the explosion.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

Great Sitkin | 3 May-9 May 2023 | Continuing ActivityCite this Report

Great Sitkin
Andreanof Islands (USA)

AVO reported that lava continued to erupt at the summit of Great Sitkin during 2-9 May. Satellite data acquired on 5 May showed that the thick lava continued to expand towards the E but remained confined to the summit crater. Seismicity was low, and during 7-8 May only a few small events were detected. Nothing significant was seen in satellite and webcam images during most of the week, though sometimes weather clouds obscured views. 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)

Ibu | 3 May-9 May 2023 | Continuing ActivityCite this Report

Ibu
Halmahera

PVMBG reported that the eruption at Ibu continued during 3-9 May. White-and-gray plumes of variable densities rose as high as 800 m above the summit and drifted in several directions. The Alert Level remained at a 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater and 3.5 km away on the N side.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Lewotolok | 3 May-9 May 2023 | Continuing ActivityCite this Report

Lewotolok
Lembata Island

PVMBG reported that the eruption at Lewotolok was ongoing during 3-9 May. Daily white-and-gray or dark gray ash plumes rose as high as 800 m above the summit and drifted NW, W, and SW. Webcam images of incandescent material being ejected above the summit were posted in daily reports during 7-8 May. 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)

Merapi | 3 May-9 May 2023 | Continuing ActivityCite this Report

Merapi
Central Java

BPPTKG reported that the eruption at Merapi (on Java) continued during 28 April-4 May and seismicity remained at elevated levels. The SW lava dome produced 190 lava avalanches that traveled as far as 2.5 km down the SW flank (upstream in the Bebeng and Boyong drainages). One pyroclastic flow traveled 2.5 km down the Bebeng drainage. Morphological changes to the SW lava dome due to continuing collapses of material were evident in webcam images. 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)

Raung | 3 May-9 May 2023 | Continuing ActivityCite this Report

Raung
Eastern Java

PVMBG reported that during 1-30 April white steam-and-gas plumes of moderate intensity rose as high as 200 m above Raung’s summit. Monitoring data along with visual observations did not suggest elevated levels of activity. The Alert Level was lowered to 1 (on a scale of 1-4) on 2 May and the pubic was reminded to stay 500 m away from the crater.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Rincon de la Vieja | 3 May-9 May 2023 | Continuing ActivityCite this Report

Rincon de la Vieja
Costa Rica

OVSICORI-UNA reported that phreatic eruptions occurred a few times at Rincón de la Vieja during 3-9 May. Phreatic events were recorded at 0100 and 2254 on 3 May, and at 1434 on 8 May, though darkness or weather clouds prevented visual confirmation. A small phreatic event occurred at 1847 on 5 May [Correction: at 1847 on 6 May.]

Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

Sabancaya | 3 May-9 May 2023 | Continuing ActivityCite this Report

Sabancaya
Peru

Instituto Geofísico del Perú (IGP) reported moderate levels of activity at Sabancaya during 1-7 May with a daily average of 23 explosions. Gas-and-ash plumes rose as high as 2 km above the summit and drifted N, E, and SE. Three thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. The Alert Level remained at Orange (the second highest level on a four-color scale) and the public were warned to stay outside of a 12-km radius.

Source: Instituto Geofísico del Perú (IGP)

Santa Maria | 3 May-9 May 2023 | Continuing ActivityCite this Report

Santa Maria
Southwestern Guatemala

INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 2-9 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 generally rose as high as 800 m and drifted SW. The explosions were also accompanied by block-and-ash flows that descended multiple flanks of the dome. Incandescence from the dome and the lava flows was visible each morning and night. Avalanches of material from the lava-flow front and margins caused ash plumes around the flanks. Activity during 5-6 May was characterized by high levels of extrusive and explosive activity; 40 explosions were recorded, producing ash plumes that rose 3.5 km above the dome and drifted SW. Ashfall was reported in San Marcos Palajunoj (8 km SW), Loma Linda (7 km W), and other nearby communities. During 6-7 May quiet rumbling sounds were heard on nearby farms. Residents were warned to stay 6 km away from the lava-dome complex.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Semeru | 3 May-9 May 2023 | Continuing ActivityCite this Report

Semeru
Eastern Java

PVMBG reported that the eruption at Semeru continued during 3-9 May and a few Volcano Observatory Notices for Aviation (VONAs) describing ash emissions were issued during the week. At 0546 on 4 May a dense white-to-gray ash plume rose 1 km above the summit and drifted S. At 0521 on 5 May and at both 0839 and 2315 on 7 May medium-to-dense white-to-gray ash plumes rose 600 m and drifted S, SW, and W. At 0809 and 0922 white-to-gray ash plumes rose 300-600 m and drifted S and W. 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)

Semisopochnoi | 3 May-9 May 2023 | Continuing ActivityCite this Report

Semisopochnoi
Aleutian Islands (USA)

AVO reported that low-level unrest continued at Semisopochnoi during 2-9 May, though it was seismically quiet for the most part, with only occasional small earthquakes. Cloudy weather often obscured satellite views. Steam emissions from the N crater of Mount Young were visible in partially clear webcam images during 3-6 May. A new NW-flank ash deposit was present on fresh snow; no signs of explosive activity were seen in geophysical data. 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)

Sheveluch | 3 May-9 May 2023 | Continuing ActivityCite this Report

Sheveluch
Central Kamchatka (Russia)

KVERT reported that the ongoing eruption at Sheveluch was generally characterized by occasional explosions, continuing lava-dome growth, incandescence, and strong fumarolic activity during 27 April-4 May. A thermal anomaly was identified in satellite images all week. Satellite data showed a gas-and-steam plume with some ash drifting 60 km SE at 2350 on 29 April. The Kamchatka Volcanological Station posted pictures and video taken during a 4 May overflight that showed three active fumaroles on the dome. Low weather clouds obscured parts of the dome area. Photos showed tephra-fall on surrounding lakes, rivers, and forests, and it was noted that lahar deposits blocked a road W of the volcano. 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

Suwanosejima | 3 May-9 May 2023 | Continuing ActivityCite this Report

Suwanosejima
Ryukyu Islands (Japan)

JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 1-8 May, and crater incandescence was reported nightly. No explosions were recorded during 1-5 May, but eruptive activity produced periodic ash plumes that rose as high as 1.6 km above the crater rim and ejected blocks 300 m from the crater. Explosions at 0701, 1200, 2001, and 2330 on 8 May generated ash plumes that rose as high as 1 km and drifted SE and SW. Explosions also occurred at 1358 and 1648, though no associated emissions were reported. 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)

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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.

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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 reported that during 7-9 May the seismic network at Bulusan recorded a total of 17 volcanic earthquakes at depths of 0-5.2 km beneath the E flank. Six of the earthquakes were tornillo-type events associated with gas movement and the other 11 events were volcano-tectonic earthquakes associated with rock fracturing. Diffuse white steam plumes rose from the active vents in the summit crater. The Alert Level was lowered to 0 (the lowest level on a scale of 0-5) on 18 January and remained unchanged. PHIVOLCS reminded the public not to enter the 4-km-radius Permanent Danger Zone (PDZ).
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

Report for Fuego
INSIVUMEH reported that activity at Fuego during 2-9 May included intense explosions, dense ash emissions, lava effusion, pyroclastic flows, and lahars. During 1-3 May there were 5-8 weak explosions per hour generating dense ash plumes that rose more than 1 km above the summit and drifted to 10-15 km W, SW, and S. Explosions were accompanied by rumbling sounds and shockwaves that vibrated nearby houses. During the morning and night incandescent material was visible 100-200 m above the crater. Avalanches descended the Ceniza (SSW) and Las Lajas (SE) drainages, sometimes reaching vegetated areas. Ashfall was reported in areas downwind including Panimache I and II (8 km SW), Morelia (9 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Finca Palo Verde, Sangre de Cristo (8 km WSW), and Yepocapa (8 km N). In the early afternoon (around 1500) on 2 May lahars descended the Las Lajas and El Jute (ESE) drainages, carrying branches, tree trunks, and blocks 30 cm to 1.5 m in diameter; about 30 minutes later similar lahars descended the Ceniza drainage. At 1618 a weak-to-moderate pyroclastic flow traveled down the Ceniza and an associated ash plume drifted W and SW. Within 30 minutes after the pyroclastic flow a lahar descended the Seca (W), carrying tree trunks and branches, and blocks up to 1.5 m in diameter.

Activity intensified at around 0200 on 4 May with a new effusive phase; by 0510 a lava flow was traveling down the Ceniza drainage, incandescent material rose above the summit, avalanches were continuous, and ash-and-gas plumes drifted SW. At around 0700 weak-to-moderate pyroclastic flows descended the Ceniza and within 1.5 hours pyroclastic flows also descended the Las Lajas. Ashfall was reported on W-flank farms and communities including Finca La Asunción, La Rochela, Panimaché I and II, Morelia, Santa Sofía, as well as others at a greater distance such as San Rafael Sumatán (19 km WSW) and San Pedro Yepocapa. By 1000 moderate-to-strong pyroclastic flows were descending the W-flank Seca and Santa Teresa ravines. Loud rumbling sounds and shock waves were reported by local residents. Ashfall continued in communities near the Ceniza and Las Lajas ravines. Ash plumes rose 2.2 km above summit and drifted more than 50 km W and SW.

Activity continued at a high level and as of a special report posted at 1235 ash plumes were still rising more than 2.2 m above the summit. Pyroclastic flows were continuing and had traveled 5-7 km down the Ceniza, Las Lajas, Seca and Santa Teresa (W) drainages; the most intense pyroclastic flow had descended the Ceniza drainage minutes earlier. The ash plumes were identified in satellite images drifting more than 100 km W and SW. Significant ashfall continued in communities downwind and minor ashfall was reported in several municipalities of the department of Suchitepéquez.

The last pyroclastic flow descended the Ceniza at 1530. Avalanches continued to be seen and heard descending multiple flanks. Ash deposits up to 2 mm thick were noted on crops, houses, and streets. Activity began to wane at about 1800, though explosions continued to produce ash plumes that rose 1.2 km above the summit. The leading edge of the ash plume was 200 km W and SW of the volcano. According to CONRED, about 1,200 residents were preemptively evacuated from their homes in San Pedro Yepocapa, Chimaltenango (21 km NNE), Panimaché I and II, El Porvenir, and Morelia. According to news articles, a section of the RN-14 highway was closed from kilometer 84 of San Juan Alotenango, Sacatepequez (9 km ENE) to kilometer 95 in Escuintla due to the pyroclastic flows. An estimated 130,000 people lived within areas exposed to ashfall.

Activity during the morning of 5 May was characterized by some weak-to-moderate explosions, ash plumes that rose 850 m above the summit, crater incandescence, and ash in the air in communities around the Ceniza, Seca, and Las Lajas drainages. Ashfall continued to impact agriculture and infrastructure in Panimaché I, Morelia, Santa Sofía, La Rochela, Los Yucales, El Porvenir, Ceylon, Finca Asunción (12 km SW), Yepocapa, Santa Lucía Cotzumalguapa (22 km SW), Siquinalá (21 km SSW), and other nearby communities. By 1230 data from seismic and infrasound monitoring networks, webcam images, satellite data, and reports from observers in the field all indicated that activity had returned to normal levels. Weak explosions at a rate of 5-6 per hour produced minor ash plumes that rose as high as 850 m and drifted 30 km W. On 6 May weak explosion generated ash plumes that rose 750 m and drifted 10 km W and SW. The lava flow was no longer incandescent. According to a news report, residents returned to their communities that same day. During 7-9 May weak explosions continued to produce ash plumes that rose as high as 750 m above the summit and drifted W and SW. Minor avalanches descended the Ceniza and crater incandescence was occasionally observed.
Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Coordinadora Nacional para la Reducción de Desastres (CONRED), Prensa Libre, Prensa Libre

Report for Gamalama
PVMBG reported that the number of deep volcanic earthquakes at Gamalama increased during 1-3 May. The seismic network recorded 11 deep volcanic earthquakes on 1 May and 14 on 2 May. During 0000-0900 on 3 May the network recorded five deep volcanic earthquakes, one shallow volcanic earthquake, five events indicating emissions, and one low-frequency earthquake. Diffuse white gas-and-steam plumes rose as high as 100 m; typically, these emissions rose as high as 300 m. PVMBG noted that the most likely hazard would be a phreatic event that could ejected material within the 1.5-km radius, though ash may be carried farther. The Alert Level remained at 2 (on a scale of 1-4); visitors and residents were warned not to approach the crater within a 1.5-km radius.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Kadovar
Based on satellite and wind model data, the Darwin VAAC reported that at 2040 on 6 May a discrete ash plume from Kadovar rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted W. The plume had dissipated by 2300.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Report for Kanlaon
PHIVOLCS issued a special notice for Kanlaon at 2030 on 4 May, noting increased seismicity and ground deformation, and ongoing elevated sulfur dioxide emissions. 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, though during the second week of April inflation was pronounced at the SE mid-flank. Real-time, continuous gas monitoring of thermal springs on the N flank detected sulfur dioxide for the first time beginning in April. Sulfur dioxide emissions at the summit crater averaged 632 tonnes per day on 1 May, lower than the average of 1,099 tonnes per day measured the day before, but higher than the average of 124 tonnes per day emitted since March. The seismic network detected 20 shallow volcanic earthquakes (M 1.2-2.4) beneath the summit crater between 2225 on 3 May until 1600 on 4 May. 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 Katla
Iceland Met Office (IMO) reported that an intense seismic swarm began at Katla at 0941 on 4 May with three earthquakes larger than M 4 occurring beneath the caldera within about 10 minutes. The Aviation Color Code was raised to Yellow, the second lowest level on a four-color scale. According to a news article the three largest events were magnitudes 4.8, 4.7, and 4.5, adjusted from previous estimates of 4.5, 4.3, and 4.2. The larger earthquakes were felt in Thórsmörk and by residents in areas S of Mýrdalsjökull glacier (the glacier that covers Katla). The intensity of the events decreased after noon, though smaller earthquakes continued. Seismicity had decreased significantly by the next day with only five events recorded during 0000-0915 on 5 May. In an update posted at 1140 the activity was described as normal, and the Aviation Color Code was lowered to Green. More than 40 earthquakes had been recorded during the previous day and no other data indicated significant changes or anomalies. It was noted that the magnitudes were unusually large and similar to events that last occurred in 2016.
Sources: Icelandic Meteorological Office (IMO), Iceland Monitor

Report for Aira
JMA reported that Minamidake Crater and Showa Crater (Aira Caldera’s Sakurajima volcano) remained active during 1-8 May. Crater incandescence was observed nightly at Minamidake Crater. Three explosions at Minamidake during 2-3 May produced small shock waves and ash plumes. The explosion at 0422 on 2 May generated an ash plume that rose 1.8 km above the crater rim and drifted SW, and ejected blocks 500-700 m from the vent. The explosion at 0241 on 3 May produced an ash plume that rose 800 m and ejected blocks to 500-700 m from the vent. Later that morning, at 1025, an explosion produced an ash plume that rose 500 m and drifted W. An ash plume from an eruptive event at 2337 on 7 May rose 1 km. At Showa Crater very small eruptive events were recorded during 1-5 May, and three eruptive events on 8 May produced ash plumes that rose as high as 1.2 km above the crater rim and drifted S and 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 that moderate eruptive activity continued at Cotopaxi during 2-9 May. Seismic activity was largely dominated by long-period earthquakes, tremors indicating emissions, and a few volcano-tectonic earthquakes. Emissions of steam, gas, and variable amounts of ash were observed daily. During 2-3 May minor ash plumes rose less than 200 m above the crater rim and drifted W. On 4 May ash plumes rose as high as 1.5 km above the crater rim and drifted SW and NW, drifting as far as the province of Manabí. On 5 May several emissions with low ash content rose as high as 300 m and drifted SW. On 7 May ash plumes rose as high as 1.1 km above the crater rim and drifted W and SW, causing minor ashfall in areas downwind including Mulaló. On 8 May a seismic station recorded a small secondary lahar. Several steam-and-gas emissions were visible during 8-9 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 27 April-4 May. A thermal anomaly was identified in satellite images on 3 May. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 3-4 May generated ash plumes that rose as high as 4 km (13,100 ft) a.s.l. and drifted SW and 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 Etna
INGV reported that a sudden explosion at Etna’s SE Crater occurred at 2325 on 6 May and produced a diffuse ash emission that rapidly dispersed around the crater area. The Aviation Color Code was raised to Yellow at 2358 and then lowered back to Green at 1148 on 7 May. Neither seismic nor infrasound data recorded changes associated with the explosion.
Source: Sezione di Catania - Osservatorio Etneo (INGV)

Report for Great Sitkin
AVO reported that lava continued to erupt at the summit of Great Sitkin during 2-9 May. Satellite data acquired on 5 May showed that the thick lava continued to expand towards the E but remained confined to the summit crater. Seismicity was low, and during 7-8 May only a few small events were detected. Nothing significant was seen in satellite and webcam images during most of the week, though sometimes weather clouds obscured views. 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 Ibu
PVMBG reported that the eruption at Ibu continued during 3-9 May. White-and-gray plumes of variable densities rose as high as 800 m above the summit and drifted in several directions. The Alert Level remained at a 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater and 3.5 km away on the N side.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Lewotolok
PVMBG reported that the eruption at Lewotolok was ongoing during 3-9 May. Daily white-and-gray or dark gray ash plumes rose as high as 800 m above the summit and drifted NW, W, and SW. Webcam images of incandescent material being ejected above the summit were posted in daily reports during 7-8 May. 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 28 April-4 May and seismicity remained at elevated levels. The SW lava dome produced 190 lava avalanches that traveled as far as 2.5 km down the SW flank (upstream in the Bebeng and Boyong drainages). One pyroclastic flow traveled 2.5 km down the Bebeng drainage. Morphological changes to the SW lava dome due to continuing collapses of material were evident in webcam images. 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 Raung
PVMBG reported that during 1-30 April white steam-and-gas plumes of moderate intensity rose as high as 200 m above Raung’s summit. Monitoring data along with visual observations did not suggest elevated levels of activity. The Alert Level was lowered to 1 (on a scale of 1-4) on 2 May and the pubic was reminded to stay 500 m away from the crater.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Report for Rincon de la Vieja
OVSICORI-UNA reported that phreatic eruptions occurred a few times at Rincón de la Vieja during 3-9 May. Phreatic events were recorded at 0100 and 2254 on 3 May, and at 1434 on 8 May, though darkness or weather clouds prevented visual confirmation. A small phreatic event occurred at 1847 on 5 May [Correction: at 1847 on 6 May.]
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

Report for Sabancaya
Instituto Geofísico del Perú (IGP) reported moderate levels of activity at Sabancaya during 1-7 May with a daily average of 23 explosions. Gas-and-ash plumes rose as high as 2 km above the summit and drifted N, E, and SE. Three thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. The Alert Level remained at Orange (the second highest level on a four-color scale) and the public were warned to stay outside of a 12-km radius.
Source: Instituto Geofísico del Perú (IGP)

Report for Santa Maria
INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 2-9 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 generally rose as high as 800 m and drifted SW. The explosions were also accompanied by block-and-ash flows that descended multiple flanks of the dome. Incandescence from the dome and the lava flows was visible each morning and night. Avalanches of material from the lava-flow front and margins caused ash plumes around the flanks. Activity during 5-6 May was characterized by high levels of extrusive and explosive activity; 40 explosions were recorded, producing ash plumes that rose 3.5 km above the dome and drifted SW. Ashfall was reported in San Marcos Palajunoj (8 km SW), Loma Linda (7 km W), and other nearby communities. During 6-7 May quiet rumbling sounds were heard on nearby farms. Residents were warned to stay 6 km away from the lava-dome complex.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Report for Semeru
PVMBG reported that the eruption at Semeru continued during 3-9 May and a few Volcano Observatory Notices for Aviation (VONAs) describing ash emissions were issued during the week. At 0546 on 4 May a dense white-to-gray ash plume rose 1 km above the summit and drifted S. At 0521 on 5 May and at both 0839 and 2315 on 7 May medium-to-dense white-to-gray ash plumes rose 600 m and drifted S, SW, and W. At 0809 and 0922 white-to-gray ash plumes rose 300-600 m and drifted S and W. 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 2-9 May, though it was seismically quiet for the most part, with only occasional small earthquakes. Cloudy weather often obscured satellite views. Steam emissions from the N crater of Mount Young were visible in partially clear webcam images during 3-6 May. A new NW-flank ash deposit was present on fresh snow; no signs of explosive activity were seen in geophysical data. 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 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 27 April-4 May. A thermal anomaly was identified in satellite images all week. Satellite data showed a gas-and-steam plume with some ash drifting 60 km SE at 2350 on 29 April. The Kamchatka Volcanological Station posted pictures and video taken during a 4 May overflight that showed three active fumaroles on the dome. Low weather clouds obscured parts of the dome area. Photos showed tephra-fall on surrounding lakes, rivers, and forests, and it was noted that lahar deposits blocked a road W of the volcano. 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 Suwanosejima
JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 1-8 May, and crater incandescence was reported nightly. No explosions were recorded during 1-5 May, but eruptive activity produced periodic ash plumes that rose as high as 1.6 km above the crater rim and ejected blocks 300 m from the crater. Explosions at 0701, 1200, 2001, and 2330 on 8 May generated ash plumes that rose as high as 1 km and drifted SE and SW. Explosions also occurred at 1358 and 1648, though no associated emissions were reported. 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)