Report on Sheveluch (Russia) — 16 May-22 May 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 May-22 May 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, 16 May-22 May 2001. Smithsonian Institution and US Geological Survey.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
Due to the occurrence of several large explosions at Shiveluch, KVERT increased the Concern Color Code to Red on 21 May. An approximately 40-minute-long eruption began at 1556 on 19 May. An ash cloud rose to an altitude of 10 km a.s.l. and drifted to the NE. Short pyroclastic flows and hot avalanches from the lava dome were restricted to areas near the lava dome. At 1802 and 1814 on 20 May a large thermal anomaly was visible on satellite imagery. At 1925 and 2014 two explosions sent ash columns to heights ranging between 4.7 and 5 km a.s.l. At 0713 on 21 May an explosion sent an ash column to 10-12 km a.s.l. AVO reported that ash was visible on satellite imagery. At 0209 on 22 May an eruption produced a mushroom-shaped ash column to a height of ~20 km a.s.l. that drifted to the SSE. Reflected incandescence was observed above the volcano from the town of Klyuchi, 46 km from the volcano. The Concern Color Code changed several times during the week; on 19 May it was raised from Yellow to Red, on 20 May it was reduced to Yellow, and the following day it was raised again to Red.
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.