Report on Sheveluch (Russia) — 21 March-27 March 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 21 March-27 March 2001
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2001. Report on Sheveluch (Russia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 21 March-27 March 2001. Smithsonian Institution and US Geological Survey.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
The KVERT reported that seismicity was mainly at background levels. On 18 March a 12-minute-long series of shallow earthquakes registered. On 22 March a 2-minute-long shallow earthquake swarm was followed by 20 minutes of weak spasmodic volcanic tremor. Another 2-minute earthquake swarm occurred shortly thereafter. These seismic bursts are thought to correspond to weak ash-gas explosions to heights of 2,000-3,000 m above the crater. On 18-19 and 22 March gas-and-steam plumes rose 200 m above the volcano. The Concern Color Code remained at Yellow.
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.