Report on Sheveluch (Russia) — March 1994
Bulletin of the Global Volcanism Network, vol. 19, no. 3 (March 1994)
Managing Editor: Richard Wunderman.
Sheveluch (Russia) Gas-and-steam plume persists; avalanches from the extrusive dome
Please cite this report as:
Global Volcanism Program, 1994. Report on Sheveluch (Russia). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 19:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199403-300270.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
During March a gas-and-steam plume was observed above the extrusive dome. The height of the plume varied from 800 to 2,500 m above the crater rim and extended 40-60 km downwind to the S, SW, and W. Weak volcanic tremor occurred for ~2-4 hours/day, and shallow volcanic earthquakes were registered at a rate of 2-5 events/day. Avalanches from the N part of the dome occurred on 17 March. Fumarolic activity from the extrusive dome was observed during the last week of March. Small explosive events may have occurred on 25 and 31 March based on interpretation of seismic activity. Weak volcanic tremor decreased during the last week of March (0.2-1.5 hours/day), but shallow volcanic earthquakes (1-5 events/day) occurred at a similar rate.
In early April, weak shallow seismic activity (3-8 earthquakes/day) accompanied the continued growth of the extrusive crater dome. Seismicity increased during the second week of April (7-23 events/day), with volcanic tremor registered for 1-3 hours/day. A gas-and-steam plume reached as high as 3 km above the crater rim on 2 April.
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.
Information Contacts: V. Kirianov, IVGG.