Report on Sheveluch (Russia) — 1 August-7 August 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
1 August-7 August 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, 1 August-7 August 2001. Smithsonian Institution and US Geological Survey.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
During the week seismic activity remained above background levels, with many small earthquakes occurring within the volcano's edifice and several different seismic signals (explosion, avalanche, collapse) recorded locally. The level of continuous spasmodic volcanic tremor increased on 28 July and again on 30 July. Gas-and-steam plumes were observed rising to a maximum height of 1 km above the dome and on the night of 1 August ash fell in the town of Klyuchi, 46 km from the volcano. One- to three-pixel thermal anomalies were occasionally visible in satellite imagery. The volcano remained at Concern Color Code Orange.
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.