Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 6 April – 12 April 2022

Aira – Kyushu (Japan) : JMA reported that very small eruptive events at Minamidake Crater (at Aira Caldera’s Sakurajima volcano) were recorded during 11-18 April. Crater incandescence was periodically visible at night.

Asosan – Kyushu (Japan) : JMA reported that no eruptions had been recorded at Asosan after the end of the last eruption in October 2021. Crater incandescence, which had been occasionally visible since December 2021, was absent beginning on 27 February. Deflation began around 27 February but stabilized in April. Observations of the crater from 17 March revealed that it had deepened, compared to pre-eruption conditions, and that water had returned. Sulfur dioxide emissions had increased to 1,600 tons per day on 25 March, but four observations made during 29 March-12 April showed values in the range of 800-1,200 tons per day. Though these values were higher than those measured in September 2021, before the eruption, they represented a decreasing trend. During a field visit on 7 April scientists observed white emissions rising from Nakadake Crater and gray pools of hot water on the crater floor. A hot spring was active on the S side of the pools. The area of the water represented about 40 percent of the crater floor and the water temperature was 71 degrees Celsius.

Dukono – Halmahera : Based on satellite and wind model data, the Darwin VAAC reported that during 13-18 April ash plumes from Dukono rose to 2.1 km (7,000 ft) a.s.l. and drifted NE, E, SE, and S.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion at Great Sitkin continued during 13-19 April, based on high-resolution satellite data. Weather clouds prevented visual observations on most days. Very low seismicity persisted.

Kilauea – Hawaiian Islands (USA) : HVO reported that lava continued to effuse from a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 12-19 April, entering an active lava lake and flowing onto the crater floor. The surface of the lava lake was active all week, and the height of the lake fluctuated. Flows occasionally overtopped perched levees. At 2315 on 10 April a flow emerged from the S side on the vent that covered areas along the southwest and western margins, and was active through 14 April. Breakouts along the N, NE, and S parts of the crater were visible during 14-19 April.

Lewotolok – Lembata Island : PVMBG reported that the eruption at Lewotolok continued during 12-19 April. Daily white-and-gray ash plumes rose as high as 50-500 m above the summit and drifted W, NW, and E.

Manam – Northeast of New Guinea : The Darwin VAAC reported that on 18 April ash plumes from Manam rose to 13.7 km (45,000 ft) a.s.l. and drifted N based on information from RVO, satellite images, and weather models. Ash had dissipated by 1540. At 2000 an ash plume was visible in a satellite image through a break in weather cloud cover drifted NE at an altitude of 4.9 km (16,000 ft) a.s.l. Ash had dissipated by 0830 on 19 April.

Merapi – Central Java : BPPTKG reported that the eruption at Merapi continued during 8-14 April. The volumes of the SW lava dome and the central lava dome were unchanged from the previous week, and seismicity remained at high levels. As many as 112 lava avalanches originating from two areas on the SW dome traveled a maximum of 2 km down the Bebeng drainage on the SW flank.

Pavlof – Alaska Peninsula, Alaska : AVO reported that the eruption at a vent on Pavlof’s upper E flank was ongoing during 12-19 April, though weather conditions sometimes prevented visual observations. Seismic tremor persisted and elevated surface temperatures were identified in satellite images almost daily. Steam emissions were seen rising above the summit in webcam images on 16 April.

Reventador – Ecuador : IG staff observed high levels of activity at Reventador during a field visit from 4 to 7 April, and noted sporadic emissions with moderate ash content. They viewed the volcano with a thermal camera and saw an active lava flow on the upper NNE flank, producing rock avalanches as it advanced. The flow was 1.7-2 km long and effused from a vent about 200 m below the summit on the NNE flank. Two inactive and cooling flows were located adjacent to the active flow. Activity continued to be high during 12-19 April, though cloudy weather conditions frequently prevented visual observations. Steam, gas, and ash plumes, often observed multiple times a day with the webcam or reported by the Washington VAAC, rose as high as 1 km above the summit crater and drifted W and NW. Crater incandescence was visible most nights and early mornings; incandescent material was visible descending the flanks during 13-14 April.

Sangay – Ecuador : IG reported that the eruption at Sangay continued at a high level, with lava flows effusing from the Ñuñurcu, Central, and Norte vents. Explosions originated from a western vent that reactivated in late 2021, and from Central vent. The Norte vent, on the N flank, had opened on 2 December 2021. Activity levels were slightly higher during 4-6 April, characterized by a higher rate of lava effusion and a satellite-detected thermal anomaly at the Norte vent on 4 April, along with a diffuse but continuously-emitted volcanic cloud that rose 1.7 km above the crater rim and drifted up to 650 km W during 5-6 April. Low-frequency tremor was also recorded during 5-6 April. Even though the eruption plume drifted notably farther than average distances recorded during 2019-2022, only minor ashfall was reported in Chauzán San Alfonso (40 km W, in Guamote canton, Chimborazo province). During 12-18 April weather clouds and rain often prevented visual and webcam observations of the volcano, though daily ash-and-gas plumes were identified in satellite images by the Washington VAAC or in webcam views; plumes rose less than 2 km above the volcano and drifted W and NW. Minor ashfall was reported in Chauzán San Alfonso. The seismic network detected signals indicating descending lahars during 12-13 and 15 April.

Semeru – Eastern Java : PVMBG reported that the eruption at Semeru continued during 13-19 April. Daily ash plumes were visible rising 300-400 m above the summit and drifted N and S, even though cloudy weather sometimes prevented visual observations. The Alert Level remained at 3 (on a scale of 1-4). The public was warned to stay at least 500 m away from Kobokan drainages within 17 km of the summit, along with other drainages originating on Semeru, including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level eruptive activity at Semisopochnoi’s North Cerberus cone continued during 12-19 April. Periods of seismic tremor were detected daily and occasional small explosions were recorded in seismic and regional infrasound data on most days. Weather cloud cover often hindered webcam and satellite views; minor, low-level ash plumes were visible in webcam images during 16-19 April.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 8-15 April, and lava-dome extrusion continued. Explosions on 9 April produced ash plumes that rose as high as 12 km (39,400 ft) a.s.l. and drifted more than 2,000 km NE during 9-10 April. Explosions during 13-14 April generated ash plumes that rose to 6-6.5 km (19,700-21,300 ft) a.s.l. and drifted 80-110 km SW and S.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that eruptive activity continued to be recorded at Suwanosejima’s Ontake Crater during 11-18 April. One explosion produced an eruption plume that rose as high as 2.7 km above the crater rim. Ashfall was reported in Toshima village (3.5 km SSW) and in other areas as far as 5 km away. No explosions were recorded during 15-18 April, though emissions rose 1.1 km.

Wolf – Isla Isabela (Galapagos) : IG reported that the eruption at Wolf continued during 13-18 April. Lava flows continued to advance towards the coast based on thermal data; satellite images showed minor advancement during 11-16 April and the end of the flow near the coastline.

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