Report on Sheveluch (Russia) — 14 May-20 May 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 May-20 May 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Sheveluch (Russia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 14 May-20 May 2003. Smithsonian Institution and US Geological Survey.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
During 9-16 May at Shiveluch seismicity was above background levels, and several small explosions occurred. Weak shallow earthquakes were recorded, and seismic data suggested that 6 ash-and-gas explosions reached heights of 1.5 km above the lava dome and hot avalanches possibly occurred. On 11 May seismic data indicated that two ash-and-gas explosions rose to 6 km a.s.l. and were possibly accompanied by hot avalanches. Video data revealed a series of ash explosions beginning on 14 May at 1550 that produced ash clouds to heights of 4.2 km a.s.l. The explosions were accompanied by several pyroclastic flows. Shiveluch remained at Concern Color 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.