Volcanos

Roundup of Global Volcanic Activity - Ongoing Activity for the week of 5 April - 11 April 2023

Aira - Kyushu (Japan) : JMA reported ongoing eruptive activity at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) during 3-10 April, with crater incandescence visible nightly. Very small eruptive events occasionally occurred. Sulfur dioxide emissions were high at 2,700 tons per day on 4 March.

Cotopaxi - Ecuador : IG reported that eruptive activity at Cotopaxi was ongoing during 4-11 April. Gas, steam, and ash plumes visible in webcam images and reported by the Washington VAAC during 4-6 and 8 April rose 200-800 m above the summit and drifted E, SE, S, and SW. Minor ashfall was reported in Mulaló (9.5 km WSW) and San Agustín (10 km W). Gas-and-steam plumes rose 300 m and drifted S and SE on 7 April. On 10 April ash plumes rose 1-1.5 km and drifted W, SW, and SE. Weather clouds prevented visual observations on the other days.

Ebeko - Paramushir Island (Russia) : KVERT reported that moderate activity at Ebeko was ongoing during 30 March-6 April and a daily thermal anomaly was identified in satellite images. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during the week generated ash plumes that rose as high as 4 km (13,100 ft) a.s.l. and drifted in various directions. Ash plumes drifted 12 km E and SW on 3 and 6 April.

Fuego - South-Central Guatemala : INSIVUMEH reported that 4-12 explosions per hour were generally recorded at Fuego during 4-11 April, generating ash plumes that rose as high as 1.1 km above the crater rim and drifted as far as 20 km W, SW, and S. Weather clouds sometimes prevented views. Daily ashfall was recorded in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), La Rochela, San Andrés Osuna, Siquinala, Ceylon, Finca La Asunción, and Finca Palo Verde. Daily block avalanches descended multiple drainages including the Ceniza (SSW), Seca (W), Trinidad (S), Taniluyá (SW), Honda, Las Lajas (SE), and El Jute (ESE), and often reached vegetated areas. Daily shock waves rattled structures in communities around the volcano and rumbling was often heard. Explosions ejected incandescent material as high as 350 m above the summit each day.

Great Sitkin - Andreanof Islands (USA) : AVO reported that lava likely continued to slowly effuse at the summit of Great Sitkin during 5-11 April, producing a thick lava flow. Seismicity was low, and during 9-10 April only a few events were detected. A satellite radar image on 2 April showed that the lava flow was mostly expanding to the E and slowly to the S into the summit crater ice field. Elevated surface temperatures were identified in satellite images during 4-6 April. Weather clouds obscured views during 7-10 April.

Karangetang - Sangihe Islands : Webcam images of Karangetang captured in the PVMBG daily reports periodically showed small areas of incandescence at the summit Main Crater (S crater) and on the flanks during 4-10 April.

Katmai - Alaska : AVO reported that on 8 April strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes blew unconsolidated ash SE across Shelikof Strait to Kodiak Island at an altitude up to 2.4 km 8,000 ft) a.s.l. The ash was originally deposited during the Novarupta eruption in 1912.

Krakatau - Sunda Strait : PVMBG reported that daily white steam-and-gas plumes rose as high as 200 m above Anak Krakatau’s summit during 5-11 April. White-and-black plumes rose as high as 300 m above the summit and drifted NE on 9 April.

Lascar - Northern Chile : SERNAGEOMIN reported that during the last two months activity at Láscar had declined to low levels, based on seismological, geodetic, geochemical, and remote sensing data, though remained above baseline. The volume of the lava dome remained unchanged, seismicity was low including small numbers of volcano-tectonic and tornillo-type events, sulfur dioxide gas emissions were low, and tephra was absent from emissions.

Lewotolok - Lembata Island : PVMBG reported that the eruption at Lewotolok was ongoing during 5-11 April. White steam-and-gas plumes were seen on most days rising as high as 500 m above the summit and drifting in multiple directions. According to the Darwin VAAC an ash plume rose to 1.8 km (6,000 ft) a.s.l., or about 370 m above the summit, on 6 April and drifted N. On 7 April white-and-gray plumes of variable densities rose 100-400 m and drifted SE and W; similar plumes on 9 April rose 200-350 m and drifted NE and E.

Merapi - Central Java : BPPTKG reported that the eruption at Merapi (on Java) continued during 31 March-6 April and seismicity remained at high levels. The SW lava dome produced 79 lava avalanches that traveled as far as 1.8 km down the SW flank (upstream in the Bebeng and Boyong drainages). One pyroclastic flow traveled 1.1 km down the SW flank, upstream of the Bebeng drainage. Morphological changes to the SW lava dome were evident in webcam images due to continuing collapses of material.

Nishinoshima - Izu Islands : JMA reported that at 1050 and 1420 on 11 April ash plumes from Nishinoshima rose 1.9 km above the crater rim and drifted NW and W.

Santa Maria - Southwestern Guatemala : INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 4-11 April. Daily explosions produced gas, steam, ash plumes that rose as high as 1 km above the complex and drifted sometimes as far as 8 km W, SW, and S; during 8-9 April the plumes drifted W and rose as high as 1.8 km. Rumbling was barely audible on nearby farms during 8-9 April. Effusion from Caliente dome fed lava flows that slowly descended the San Isidro and Zanjón Seco drainages on the W and SW flanks. Incandescence from the dome and the lava flows was visible nightly and some early mornings. Block avalanches from the dome, and from both the ends and sides of the flows, descended the S, SW, and W flanks were reported almost daily.

Semeru - Eastern Java : PVMBG reported that the eruption at Semeru continued during 5-11 April and a few Volcano Observatory Notices for Aviation (VONAs) were issued through the week. At 0559 on 8 April a dense white-to-brown plume rose 800 m above the summit and drifted NE. About an hour and a half later, at 0732, a white-to-gray plume rose 600 m and drifted N. At 0635 and 2218 on 10 April variable white-and-gray plumes rose 500-800 m and drifted N and NE. At 0535 on 11 April a dense white-and-gray plume rose 500 m and drifted N.

Semisopochnoi - Aleutian Islands (USA) : AVO reported that low-level unrest continued at Semisopochnoi during 5-11 April. An extensive low-altitude steam plume drifted more than 400 km during 4-6 April and was likely related to volcanic emissions but did not appear to contain ash. Several small explosions were detected on 5 April, and periods of seismic tremor and local earthquakes were recorded during 5-6 April, but seismicity was quiet during the rest of the week. Clouds obscured webcam and satellite views during 7-10 April.

Suwanosejima - Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 3-10 April. Eruptive activity produced ash plumes that rose as high as 1.6 km above the crater rim and drifted mainly SE, E, and N. Large blocks were ejected as far as 300 m from the vent. Crater incandescence was visible at night during 3-7 April and one explosion was detected during 7-10 April.