Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 4 December – 10 December 2019

Aira | Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 2-9 December. There were 15 explosions and four non-explosive eruptive events detected by the seismic network. Ash plumes rose 2.3-2.6 km above the crater rim and blocks were ejected as far as 1.7 km away. The Alert Level remained at 3 (on a 5-level scale).

Aira | Kyushu (Japan) : JMA reported that incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible at night during 2-9 December. There were 15 explosions and four non-explosive eruptive events detected by the seismic network. Ash plumes rose 2.3-2.6 km above the crater rim and blocks were ejected as far as 1.7 km away. The Alert Level remained at 3 (on a 5-level scale).

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 4-9 December ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted in multiple directions. 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 30 November and 1-2 and 5 December that sent ash plumes up to 3 km (10,000 ft) a.s.l. Ash plumes drifted NE and E. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Karangetang | Siau Island (Indonesia) : PVMBG reported that during 2-8 December lava continued to effuse from Karangetang’s Main Crater (S), traveling as far as 1.8 km down the Nanitu, Pangi, and Sense drainages on the SW and W flanks. Sometimes dense white plumes rose to 200 m above the summit. Incandescence from both summit craters was visible at night. The Alert Level remained at 2 (on a scale of 1-4).

Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that Strombolian activity at Klyuchevskoy was visible on 29 November and 1 December, the same days a weak thermal anomaly was identified in satellite images. The Aviation colour Code remained at Orange.

Reventador | Ecuador : IG reported that during 8-15 October seismic data from Reventador’s network indicated a high level of seismic activity, including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions. Weather sometimes prevented views of the summit area, although during clear conditions ash, gas, and steam plumes were visible rising sometimes higher than 1 km above the crater rim and drifting N, NW, W, and SW. Crater incandescence was periodically observed at night. Blocks rolled 500-700 m down the flanks in multiple directions during 7-10 December.

Sangay | Ecuador : IG reported that the eruption at Sangay that began on 7 May was continuing as of 4 December without a notable increase or decrease in activity levels. Activity was concentrated at two eruptive centers: the Central Crater and the Ñuñurcu dome (located 190 m SSE of Central Crater). Sporadic explosions at Central Crater produced ash plumes that rose as high as 2 km above the crater rim and drifted mainly NE during the previous month. Minor ashfall was recorded in the towns of Alao (20 km NW), Cebadas (35 km WNW), and Guaguallá (Chimborazo province), in Macas (42 km SSE, Morona-Santiago province), and in the Azuay province. Almost continuous lava effusion from the Ñuñurcu dome fed lava flows that traveled down the SE flank. Collapses along the margins of the lava flows generated small pyroclastic flows and small rockfalls that reached the upper channel of the Río Volcán. These deposits created dams which were remobilized by rainfall into lahars, which in turn partially dammed parts of the river at the confluence of the Río Upano. Parque Nacional Sangay and IG-EPN staff measured deposits at the confluence that were more than 2 m thick on 27 November; similar deposits were observed along a 16-km stretch upsteam. Sulfur dioxide emissions up to 640 tons/day were detected by satellite in recent weeks, and a strong sulfur odor was noted around 1 km above the crater rim during a 3 December overflight.

Sangeang Api | Indonesia : The Darwin VAAC reported that during 4-5 and 7-9 December discrete ash emissions from Sangeang Api rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted NW, W, and SW. A thermal anomaly was visible on 27 November. The Alert Level remained at 2 (on a scale of 1-4).

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 29 November-6 December. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Shishaldin | Fox Islands (USA) : AVO reported that elevated surface temperatures at Shishaldin were identified in satellite images during 3-4 December consistent with lava effusion, and a pilot confirmed active lava flows on the flank. Continuous tremor was recorded by the seismic network during 4-5 December. Seismicity, including Strombolian explosion signals, continued to increase until 2100 on 5 December and then afterwards was characterized by episodic tremor bursts and occasional Strombolian activity. Intermittent, very minor, and low-level ash or steam emissions near the summit and along the N flank were visible in clear webcam views on 5 December. A new lava flow had traveled 1.4 km down the NW flank. The eruption either slowed or paused during 6-7 December as evidenced by decreased seismicity and slightly elevated surface temperatures in satellite data. Temperatures again increased and were slightly elevated during 7-9 December, likely signifying renewed lava effusion. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.

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