Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 2 December 2020 – 8 December 2020

Aira – Kyushu (Japan) : JMA reported that during 30 November-7 December incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was often visible nightly. An explosion on 2 December produced an eruption plume that rose 1 km above the crater rim and blended into weather clouds. Volcanic bombs were ejected 1-1.3 km away from the crater. That same day the sulfur dioxide emission rate was high, at 2,500 tons per day. During 4-7 December two eruption plumes rose as high as 1.2 km above the crater rim. 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 4-7 December ash plumes from Dukono rose to 2.1 km (7,000 ft) a.s.l. and drifted NE, E, and SE. 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 28-30 November and 3 December that sent ash plumes up to 4.5 km (14,800 ft) a.s.l. and drifted NE and E. Ashfall was reported in Severo-Kurilsk on 28 November. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Ibu – Halmahera (Indonesia) : PVMBG reported that during 2-8 December gray-and-white ash plume from Ibu rose 200-800 m above the summit and drifted N and E. There were 70-81 eruptive events per day recorded during 2-4 and 6-8 December. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater and 3.5 km away on the N side.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that strong explosions at Karymsky were last observed on 8 November 2019 and a thermal anomaly was last visible in satellite images on 19 November 2019. Gas-and-steam emissions persist. Since activity had significantly decreased, the Alert Level was lowered to Yellow (the second lowest level on a four-colour scale) on 3 December.

Klyuchevskoy – Central Kamchatka (Russia) : KVERT reported that Strombolian and Vulcanian activity at Klyuchevskoy continued during 27 November-4 December and lava advanced down the Apakhonchich drainage on the SE flank. A large, bright thermal anomaly was identified daily in satellite images. During 20-21 and 23-26 November steam-and-gas plumes with some ash rose to 7 km (23,000 ft) a.s.l. and drifted 300 km NW and E. The Aviation colour Code remined at Orange (the second highest level on a four-colour scale).

Korovin – Andreanof Islands (USA) : Seismic activity at Korovin had decreased, and satellite images showed no signs of unrest over the previous several weeks. AVO lowered the Alert Level to Green and the Aviation colour Code to Normal on 3 December.

Nevado del Ruiz – Colombia : Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that during 1-8 December seismicity at Nevado del Ruiz was generally characterized by higher number of earthquakes that had larger magnitudes than the previous week. Several episodes of drumbeat signals were recorded, indicating ascent or growth of a lava dome in Arenas Crater. Gas-and-ash emissions were sometimes visible in webcam images. Two thermal anomalies were visible in satellite data. The Alert Level remained at 3 (Yellow; the second lowest level on a four-colour scale).

Semeru – Eastern Java (Indonesia) : PVMBG reported that the eruption at Semeru continued during 1-8 December. Rock avalanches were recorded by the seismic network almost daily and were visible most days, traveling 200-1,500 m down the Kobokan drainage. Eruptive events and rockfalls generated pyroclastic flows that traveled as far as 2.5 km down the Kobokan drainage on the SE flank during 1-3 and 5-6 December. BNPB noted that deposits from the 1 December pyroclastic flow were as thick as 15 m. According to the Darwin VAAC, ash plumes rose to altitudes of 4-6.1 km (13,000-20,000 ft) a.s.l., or 300-2,400 m above the summit, and drifted E and NE during 2 and 5-6 December. PVMBG noted that incandescent material was ejected 50-100 m above the summit during 5-8 December. The Alert Level remained at 2 (on a scale of 1-4), with a general exclusion zone of 1 km and extensions to 4 km in the SSE sector.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 27 November-4 December. A gas-and-steam plume drifted 60 km NE on 30 November. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Sinabung – Indonesia : PVMBG reported that an ash plume rose as high as 500 m above Sinabung’s summit on 2 December. Block avalanches were recorded by the seismic network almost daily, though they were not visually confirmed; however, on 6 December, they were observed traveling 300-500 m down the E and SE flanks. The Alert Level remained at 3 (on a scale of 1-4), with a general exclusion zone of 3 km that extends 5 km SE and 4 km NE.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported nighttime incandescence and intermittent eruptive activity at Suwanosejima’s Ontake Crater during 27 November-4 December. A total of 17 explosions were recorded, ejecting bombs up to 600 m away from the crater and producing gray-and-white plumes that rose 1.5 km above the crater rim. Ashfall was reported in Toshima village (4 km SSW). The Alert Level remained at 2 (on a 5-level scale).

Villarrica – Chile : SERNAGEOMIN reported that a long-period (LP) event and associated explosion were recorded by Villarrica’s seismic network at 1844 on 5 December. An ash plume rose 160 m and drifted SSE, depositing ash onto the flanks. Incandescent material was also ejected onto the SSE flanks. The Alert Level remained at Yellow, the second lowest level on a four-colour scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the municipalities of Villarrica, Pucón (16 km N), Curarrehue, and the commune of Panguipulli, and the exclusion zone for the public of 500 m around the crater.

Whakaari/White Island – North Island (New Zealand) : GeoNet reported that Whakaari/White Island observations and monitoring data indicated a gradual trend to lower activity levels during the previous two weeks. An overflight of the island on 2 December confirmed that ash emissions stopped and were not visible in satellite images during 2-7 December. Volcanic tremor levels and the number of local earthquakes decreased. Deformation data indicated subsidence around the active vents and parts of the Main Crater wall. Hot steam-and-gas emissions persisted. The Volcanic Alert Level was lowered to 1 and the Aviation colour Code was lowered to Green on 7 December.

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