Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 14 April 2021 – 20 April 2021

Aira – Kyushu (Japan) : JMA reported that during 12-19 April incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible nightly. There was a total of nine explosions and one eruptive event. Ash plumes rose 1-2 km above the summit and bombs were ejected 800-1,300 m away from the crater. The sulfur dioxide emission rate was high at 2,400 tons per day on 12 April. The Alert Level remained at 3 (on a 5-level scale).

Dukono – Halmahera (Indonesia) : Based on satellite and wind model data, the Darwin VAAC reported that during 13-20 April ash plumes from Dukono rose to 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted E and NE. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko – Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 9-16 April that sent ash plumes to 3.6 km (11,800 ft) a.s.l. and drifted in multiple directions. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Kadovar – Papua New Guinea : Based on satellite and wind model data, the Darwin VAAC reported that on 15 April ash plumes from Kadovar rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted W.

Kilauea – Hawaiian Islands (USA : HVO reported that the W vent on the inner NW wall of Kilauea’s Halema`uma`u Crater continued to supply the lava lake during 14-20 April. Lava flowed at a low rate from the main vent into the lake through crusted-over channels and submerged inlets. The depth of the lake was about 226-227 m and lava continued to circulate in the W part, though the active area continued to shrink; the E half of the lake remained solidified. Lava sometimes overflowed the margins of the lake. The sulfur dioxide emission rate was 950 tons/day on 14 April. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that the eruption at Lewotolok continued during 13-19 April. Gray-and-white ash plumes rose as high as 1.5 km above the summit and drifted E and W. Rumbling was often audible. Incandescent material was ejected 300-1,000 m above the summit during 14-16 April. Incandescent material was ejected to the E during 9 and 11-12 April. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 4 km away from the summit crater.

Merapi – Central Java (Indonesia) : BPPTKG reported that the lava dome just below Merapi’s SW rim and the lava dome in the summit crater both continued to extrude lava during 9-15 April. The SW rim lava-dome volume was an estimated 1,024,800 cubic meters on 15 April, with a growth rate of about 12,200 cubic meters per day, and continued to shed material down the flank. A total of six pyroclastic flows traveled a maximum of 1.8 km down the SW flank. Incandescent avalanches, recorded 119 times, traveled as far as 1.5 km down the SW flank. The volume of the summit lava dome was 1,681,000 cubic meters on 14 April. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 5 km away from the summit.

Popocatepetl – Mexico : CENAPRED reported that each day during 13-20 April there were 14-34 steam, gas, and ash emissions from Popocatépetl and periods of tremor lasting from 5-15 hours. Two volcanic earthquakes were recorded at 1054 and 2354 on 16 April. Minor crater incandescence was visible overnight during 17-18 April. A M 1.3 volcano-tectonic earthquake was recorded at 2057 on 18 April. The Alert Level remained at Yellow, Phase Two (middle level on a three-colour scale).

Raung – Eastern Java (Indonesia) : PVMBG reported that gray-and-white ash plumes rose 50-400 m above Raung’s summit during 13-14 April and drifted N, NE, E, and S. Emissions were white and rose as high as 400 m during 15-16 and 19 April. Weather conditions prented visual observations on some days. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Sabancaya – Peru : Instituto Geofísico del Perú (IGP) reported a daily average of 91 explosions at Sabancaya during 12-18 April. Gas-and-ash plumes rose as high as 2.3 km above the summit and drifted S, SW, NW, and N. Eight thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. Minor inflation continued to be detected near Hualca Hualca (4 km N). The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 12-km radius.

Sangay – Ecuador : IG reported a high level of activity at Sangay during 13-20 April. Seismicity was characterized by daily explosions, long-period earthquakes, lahar events, and signals indicating emissions. Weather clouds and rain often prevented visual observations of the volcano, though based on the Washington VAAC and webcam images, ash plumes were visible during 13-14 and 17-20 April rising 600-2,400 m above the summit and drifting mainly N, NW, and W. The seismic network occasionally recorded lahar signals, especially during 14-16 April. Ashfall was reported in Chimborazo and Guamote (40 km WNW) on 17 April, and crater incandescence was visible through the night of 19-20 April.

Semeru – Eastern Java (Indonesia) : PVMBG reported that at 0650 on 19 April an ash plume from Semeru rose 400 m above the summit and drifted W. The Alert Level remained at 2 (on a scale of 1-4), with a general exclusion zone of 1 km and extensions to 5 km in the SSE sector.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 9-16 April. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Sinabung – Indonesia : PVMBG reported that on 13 April eruptive events at Sinabung generated ash plumes that rose 500-1,600 m above the summit. Avalanches of material traveled 1-1.5 km. On 14 April gray ash plumes rose 500 m above the summit and avalanches traveled 500-700 m down the E and SE flanks. During 15-20 April white plumes were often seen rising as high as 700 m, though weather conditions sometimes prevented visual observations. The Alert Level remained at 3 (on a scale of 1-4), with a general exclusion zone of 3 km and extensions to 5 km in the SE sector and 4 km in the NE sector.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that incandescence from Suwanosejima’s Ontake Crater was visible at night during 9-16 April. Seven explosions generated ash plumes that rose as high as 1.5 km above the crater rim and ejected bombs 400 m away. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 2 and the public was warned to stay 1 km away from the crater.

Tanaga – Andreanof Islands (USA) : AVO reported that communication was reestablished with two seismic stations on Tanaga, making a total of four operational stations. On 19 April AVO changed both the Aviation colour Code and the Volcano Alert Level to Green and Normal, respectively, reflecting the resumption of seismically monitoring unrest.

Ugashik-Peulik – United States : AVO reported a loss of operation and communication with seismic stations that monitor Ugashik-Peulik, likely caused by snow cover. Both the Aviation colour Code and the Volcano Alert Level were changed to Unassigned on 19 April, reflecting the inability to locate earthquakes to detect unrest. Monitoring will continue with the remaining seismic stations, regional infrasound networks, lightning detection, and satellite images.

Ukinrek Maars – United States : AVO reported a loss of operation and communication with seismic stations that monitor Ukinrek-Maars, likely caused by snow cover. Both the Aviation colour Code and the Volcano Alert Level were changed to Unassigned on 19 April, reflecting the inability to locate earthquakes to detect unrest. Monitoring will continue with the remaining seismic stations, regional infrasound networks, lightning detection, and satellite images.

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