Roundup of Global Volcanic Activity – Ongoing Activity for the week of 3 May – 9 May 2023
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 6 May.
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.
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.
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.
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.
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.
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.