Report on Sheveluch (Russia) — 5 December-11 December 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 5 December-11 December 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, 5 December-11 December 2001. Smithsonian Institution and US Geological Survey.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
A lava dome continued to grow in Shiveluch's active crater, and seismic activity remained above background levels. Many weak, shallow earthquakes occurred within the volcano's edifice, along with about 30 earthquakes with magnitudes greater than or equal to 1.7. Other local shallow seismic events (possible collapses, avalanches, or possible weak gas-ash explosions) and episodes of weak volcanic tremor were registered. During 1 December, a gas-and-steam plume rose 400 m above the dome and extended 5 km to the E and NW. According to visual reports from Klyuchi town, at 0910 a short-lived explosive eruption sent an ash plume to ~2 km above the dome. This explosion was visible by airplane pilots. Several thermal anomalies were visible on satellite imagery.The volcano remained at Color Concern Code 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.