Report on Sheveluch (Russia) — 25 August-31 August 2021
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 25 August-31 August 2021
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2021. Report on Sheveluch (Russia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 25 August-31 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 lava dome at Sheveluch continued to grow and produced hot lava avalanches during 20-27 August. A daily bright thermal anomaly was identified in satellite images and gas-and-steam plumes containing some ash drifted 307 km NE, E, and SE. At 1100 on 29 August an ash plume 14x15 km in dimension drifted 30 km W at altitudes of 2.5-3 km (8,200-10,000 ft) a.s.l. On 28 August the Kamchatka Branch of Geophysical Services (KBGS; Russian Academy of Sciences) posted photos of the incandescent dome and avalanches, noting that small landslides and hot avalanches periodically traveled down the S and SE flanks of the dome. Larger landslides were observed 2-4 times per night. 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 1,300 km3 andesitic volcano is one of Kamchatka's largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. 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 occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. 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.