Report on Sheveluch (Russia) — 19 September-25 September 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 19 September-25 September 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Sheveluch (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 19 September-25 September 2012. Smithsonian Institution and US Geological Survey.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
Based on visual observations and analyses of satellite data, KVERT reported that during 14-21 September a viscous lava flow continued to effuse on the NW flank of Shiveluch's lava dome, and was accompanied by hot avalanches and fumarolic activity. A strong explosion on 18 September generated an ash plume that rose to an altitude of 8 km (26,300 ft) a.s.l. An ash plume rose to an altitude of 3.5 km (11,500 ft) a.s.l. on 20 September. Satellite imagery showed a thermal anomaly on the lava dome on 14 and 19 September, and an ash plume drifting 2,000 km SE during 17-20 September. The Aviation 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.