Report on Sheveluch (Russia) — 23 February-1 March 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 23 February-1 March 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Sheveluch (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 23 February-1 March 2011. 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 moderate seismic activity was detected at Shiveluch during 18-25 February. A thermal anomaly over the lava dome was observed daily in satellite imagery. Gas and steam activity was observed during 21-24 February and ash plumes rose to an altitude of 5.5 km (18,000 ft) a.s.l. during 22-23 February. Ash plumes observed in satellite imagery drifted more than 220 km SE at altitudes below 6 km (19,700 ft) a.s.l. during 23-24 February. The Aviation Color Code remained at Orange.
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.