Report on Sheveluch (Russia) — 28 August-3 September 2019
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 28 August-3 September 2019
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2019. Report on Sheveluch (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 28 August-3 September 2019. 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 a thermal anomaly over Sheveluch’s lava dome was identified daily in satellite images during 22-25 August. Ash plumes on 25 August rose to 4.5-5 km (14,800-16,400 ft) a.s.l. and drifted more than 500 km NW. At 1510 on 29 August explosions produced ash plumes that rose to 10 km (32,800 ft) a.s.l. The leading part of the plume drifted W and then curved counterclockwise to the S, then E, and finally drifted 550 km N. Explosions at 1957 on 30 August produced ash plumes that rose to 7-7.5 km (23,000-24,600 ft) a.s.l. and drifted 50 km SSE. Ash plumes drifted SE at an altitude of 5.5 km (18,000 ft) a.s.l. on 3 September. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Geologic Background. 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.