Report on Sheveluch (Russia) — 21 January-27 January 2009
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 21 January-27 January 2009
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2009. Report on Sheveluch (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 21 January-27 January 2009. Smithsonian Institution and US Geological Survey.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
KVERT reported that seismic activity at Shiveluch was above background levels during 16-23 January. Based on interpretations of seismic data, possible ash plumes rose to altitudes of 5.5 km (18,000 ft) a.s.l. on 17 and 21 January and to an altitude of 3 km (9,800 ft) a.s.l. on the other days during the reporting period. Gas-and-steam emissions were noted. On 21 January, an ash plume that was visible on a web camera rose to an altitude of about 4.5 km (14,800 ft) a.s.l. Analysis of satellite imagery revealed a large daily thermal anomaly over the lava dome, gas-and-steam plumes that drifted about 130 km SE, SW, and W during 16-17 and 19-20 January, and an ash plume that drifted 65 km SW on 18 January. The Level of Concern Color Code remained at Orange.
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.