Report on Sheveluch (Russia) — 6 November-12 November 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 6 November-12 November 2002
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Sheveluch (Russia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 6 November-12 November 2002. Smithsonian Institution and US Geological Survey.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
KVERT raised the Concern Color Code at Shiveluch from Yellow to Orange on 11 November. Visual observations revealed that on the 4th at 1020, the 5th at 0830, and the 6th at 1318, short-lived explosions sent ash-and-gas plumes to heights of approximately 3.5, 1.5, and 2 km above the dome, respectively. During 8-11 November, seismicity remained above background levels. Thermal anomalies and a faint ~11-km-long plume (on the 8th) were visible on satellite imagery, but ash was not. Seismic data on the 11th indicated possible hot avalanches and several ash-and-gas explosions sending clouds up to 5.5 km above the dome.
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.