Report on Sheveluch (Russia) — 7 March-13 March 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 7 March-13 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, 7 March-13 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 during 2-6 March, several series of shallow earthquakes were registered, with some followed by weak spasmodic volcanic tremor. The bursts of activity may have corresponded to weak ash-and-gas explosions that rose to heights of 2-3 km above the crater. During 3-4 March, visual and satellite-based data revealed that a gas-and-ash plume rose 300-800 m above the crater and drifted more than 50 km to the E. At 1545 on 7 March seismic data indicated the probable occurrence of a short-lived gas-and-ash explosion, accompanied by a series of shallow and high-frequency earthquakes for ~15 minutes. Observers in Klyuchi town reported that at 1600 the same day the ash-and-gas plume rose 1.5 km above the lava dome and extended to the NW. According to a pilot report, at 1620 the ash plume was visible at a height of 10 km above the volcano drifting towards the NE. The AVO reported that satellite imagery at 1715 showed two plumes: one was at a low altitude, composed mostly of steam, and drifted to the E; the other was located 7-8 km a.s.l., composed mostly of ash, and drifted to the N. At 1625 the Tokyo VAAC detected the ash cloud on GMS-5 imagery at a height of ~10 km a.s.l. The ash cloud was no longer visible on satellite imagery by 0342 on 8 March. 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.