Report on Sheveluch (Russia) — 18 August-24 August 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
18 August-24 August 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Sheveluch (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 18 August-24 August 2021. Smithsonian Institution and US Geological Survey.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
KVERT reported that the growth of the lava dome at Sheveluch continued during 14-24 August, accompanied by strong fumarolic activity, dome incandescence, and hot avalanches. A thermal anomaly was identified in satellite imagery all week. Gas-and-steam plumes containing some ash drifted 370 km SW, E, and SE. On 21 and 24 August ash plumes rose to 4 km (13,100 ft) a.s.l. and drifted 86 km SE and 3.5 km (11,500 ft) a.s.l. and drifted as far as 100 km SE, respectively. The Tokyo VAAC reported ash plumes during 17-25 August that rose to 3.7-5.5 km (12,000-18,000 ft) a.s.l. and drifted E, S, SE. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Geological Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 km3 volcano is one of Kamchatka's largest and most active volcanic structures. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera.