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, these notices are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of eruptions during the week, but rather a summary of activity that meet selected criteria. Carefully reviewed, detailed reports are published monthly in the Bulletin of the Global Volcanism Network. The World Organization of Volcano Observatories (WOVO) website (https://wovo.iavceivolcano.org/) lists the regional volcano observatories that have the most authoritative data for many of these events.

The Darwin VAAC reported that an ash plume from Bagana was identified in satellite images rising to 2.1 km (7,000 ft) a.s.l. and drifting SW at 0820 on 22 April. The plume had dissipated by 1420.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

OVSICORI-UNA reported continuing gas-and-steam emissions rose from vents Boca A and Boca B on the crater floor of Poás. Ash ceased to be detected in the emissions at some point during 16-17 April but was again present during 22-23 April.

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

PVMBG raised the Alert Level for Ruang to 2 (on a scale of 1-4) at 1300 on 16 April due to intensifying seismicity. A minor eruption began at around 1337 on 16 April and produced dense white emissions; at 1600 the Alert Level was raised to 3 (on a scale of 1-4). Explosive activity began at 2145 and ash plumes rose 2 km above the summit. Activity continued to escalate. An explosive pulse was recorded at 0108 on 17 April. According to the Darwin VAAC ash plumes had risen to 9.1 km (30,000 ft) a.s.l. and drifted W by 0230, and at 0300 they reached 12.2 km (40,000 ft) a.s.l. and detached from the summit. Ash plumes at a lower altitude of 4.6 km (15,000 ft) a.s.l. drifted WSW. BNPB reported that 828 people from Pumpente and Laingpatehi villages evacuated to neighboring Tagulandang Island to the NE and the communication network in Laingpatehi village was non-operational. Photos showed incandescent material being ejected above the summit, incandescent material on the flanks, pyroclastic density currents descending the flanks, and dense ash plumes with lightning rising into dark, nighttime skies. Another explosive pulse was recorded at 0505 according to PVMBG, and the VAAC noted that by 0600 ash plumes had risen to 13.7 km (45,000 ft) a.s.l. and drifted W and NW. The plume was detached from the summit by 0713. Additional smaller eruptive events produced ash plumes that rose to 1.5 km (5,000 ft) a.s.l. and drifted E. PVMBG recorded bigger eruptive pulses at 1800 and 2015 on 17 April. Roaring and booming noises were sometimes heard, with gray-to-black ash plumes at 2015 and a felt earthquake. According to the VAAC ash plumes rose to 15.2 km (50,000 ft) a.s.l. by 2000 and at least to 19.2 km (63,000 ft) a.s.l. by 2020; the plumes drifted NW. PVMBG raised the Alert Level to 4, the highest level, at 2100 on 17 April noting that seismicity continued to increase, ash plumes were getting taller, and incandescent rocks were ejected as far as 5 km with some reaching Tagulandang Island. The public was warned to stay 6 km away from Ruang?s main crater. Several residents in Tagulandang were hit with tephra and some received medical treatment according to BNPB. Ashfall was recorded in as many as 10 villages in two sub-districts on Tagulandang and in several sub-districts of North Minahasa Regency (75 km SSW) including West Likupang, Wori, East Likupang, and South Likupang. Communication networks in Lumbo Village on Tagulandang were not properly functioning. An estimated 6,045 people living in the W part Tagulandang evacuated. According to a news article, there was damage to more than 3,000 homes, two churches, and an elementary school. Multiple ash layers were identified in a satellite image 2310 on 17 April according to the VAAC; ash at 16.8 km (55,000 ft) a.s.l. drifted NW and E and ash at 14.3 km (47,000 ft) a.s.l. drifted WSW. At 0310 on 18 April ash plumes rose to 12.2 km and drifted WNW and W and detached from the volcano by 0600; earlier high-level plumes continued to expand as they drifted NW. According to a news report the Sam Ratulangi International Airport, 98 km SW in Manado, North Sulawesi, closed on 18 April due to the presence of ash. The VAAC continued to track the plumes; lower-altitude plumes at 7.6 km (25,000 ft) a.s.l. drifted SE. The higher plumes, between 10.7-15.2 km (35,000-50,000 ft) a.s.l., continued to drift NW and WNW and had dissipated by 1710 on 19 April, though sulfur dioxide continued to be tracked W. Weather clouds began to obscure the plumes. On 19 April PVMBG reported that ash plumes rose 400-750 m above the summit and drifted S. During 20-21 April the VAAC issued notifications of ash plumes rising 1.5-2.1 km (5,000-7,000 ft) a.s.l. and drifting S and SW based on satellite images and information from PVMBG. The closure of the Sam Ratulangi International Airport affected 150 flights and about 19,085 passengers as of 20 April based on a news report; the airport resumed operations at noon on 22 April. PVMBG reported that during 21-23 April dense white steam-and-gas plumes rose as high as 200 m and drifted SW, W, and NW. The Alert Level was lowered to 3 at 0900 on 22 April because activity had decreased. Residents were warned to stay 4 km away from the crater.

Sources: Antara News,Antara News,Badan Nacional Penanggulangan Bencana (BNPB) ,Darwin Volcanic Ash Advisory Centre (VAAC),Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM),Tempo,VOI

PVMBG reported that eruptive activity continued at Semeru during 17-23 April. White-and-gray or occasionally white-to-brown ash plumes rose 300-1,500 m above the summit and drifted in multiple directions on most days. Eruptive events were recorded during 17, 19-20, and 22-23 April; no emissions were visible, possibly due to weather conditions. BNPB reported that intense rain on 18 April caused lahars in the Regoyo River basin and in the Mujur and Glidik watersheds in the Lumajang Regency during 18-19 April. Three deaths were reported: one person was buried by landslides in the Pronojiwo District and two were swept away by lahars in the Candipuro District. Lahars damaged nine bridges and destroyed an additional eight bridges, flooded the Candipuro National Road, and damaged three houses. As many as 32 families self-evacuated. The Alert Level remained at 3 (the third highest level 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, 500 m from the banks of the Kobokan drainage as far as 17 km from the summit, and to avoid other drainages including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.

Sources: Badan Nacional Penanggulangan Bencana (BNPB) ,Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

PHIVOLCS reported that sulfur dioxide emissions at Taal had decreased the last week and averaged 2,104 tonnes per day (t/d) on 18 April; despite the decrease averages in 2024 remained high at 9,698 t/d. Short-lived phreatic events were recorded during 0850-0852, 0909-0912, 1102-1107, and 1710-1714 on 20 April based on seismic data and webcam images. White steam plumes rose 300-600 m above Main Crater and drifted WSW, SW, and NW. During 21-23 April emissions rose 600-900 m and drifted NW and SW and observers noted pronounced upwelling of gases and hot fluids in the lake. The Alert Level remained at 1 (on a scale of 0-5), and PHIVOLCS reminded the public that the entire Taal Volcano Island was a Permanent Danger Zone (PDZ) and to take extra precautions around Main Crater, when boating on Taal Lake, and along the Daang Kastila fissure.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

JMA reported ongoing eruptive activity at Minamidake Crater (Aira Caldera?s Sakurajima volcano) during 15-22 April with nighttime crater incandescence. Very small eruptive events were occasionally recorded. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 2 km away from both craters.

Source: Japan Meteorological Agency (JMA)

PVMBG reported that the eruption at Dukono was ongoing during 17-23 April. Gray-and-white ash plumes rose 100-1,200 m above the summit and drifted E, N, and W almost daily; emissions were not observed on 22 April. The Alert Level remained at Level 2 (on a scale of 1-4), and the public was warned to remain outside of the 3-km exclusion zone.

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

KVERT reported that moderate explosive activity was ongoing at Ebeko during 11-18 April. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 12-17 April generated ash plumes that rose as high as 4 km (13,100 ft) a.s.l. and drifted SW, SE, and E. A thermal anomaly was identified in satellite images on 13 and 16-17 April; on other days either no activity was observed or weather conditions prevented views. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are UTC; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN) reported that the eruption at Fernandina continued during 16-23 April. Daily thermal anomalies were identified in satellite images. Sulfur dioxide emissions, measured using satellite data, fluctuated between about 207 and 1,418 tons per day. Gas-and-steam emissions rose from the area where lava entered the ocean; a 16 April photo showed three bright areas where lava entered the water and gas-and-steam plumes rising from the entries. During 21-22 April satellite images showed another lobe of lava low on the flank, descending towards the shoreline.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)

AVO reported that slow lava effusion continued in Great Sitkin?s summit crater during 17-23 April. Slightly elevated surface temperatures were identified in satellite images during 17-18 April. Seismicity was low with a few small daily earthquakes recorded by the seismic network. Weather clouds partly or mostly obscured satellite and webcam views during most of the week. The Volcano Alert Level remained at Watch (the third level on a four-level scale) and the Aviation Color Code remained at Orange (the third color on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

PVMBG reported that Ibu continued to erupt during 17-23 April. White-and-gray ash plumes rose 200-2,500 m above the summit and drifted in multiple directions on 17 and 21 April. White steam-and-gas plumes rose 200-600 m above the summit and drifted in multiple directions on the other days. The Alert Level remained at 2 (the second highest level on a four-level scale), with the public advised to stay outside of the 2 km hazard zone and 3.5 km away from the N area of the active crater.

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

Satellite data showed an area of yellow-green discolored water that was about 4.2 km in diameter in the vicinity of the submarine Kavachi volcano on 19 April. A more diffuse plume of discolored water extended another ~11 km NE before dissipating.

Source: Copernicus