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Report on Sheveluch (Russia) — August 1998


Sheveluch

Bulletin of the Global Volcanism Network, vol. 23, no. 8 (August 1998)
Managing Editor: Richard Wunderman.

Sheveluch (Russia) Series of shallow earthquakes in late July

Please cite this report as:

Global Volcanism Program, 1998. Report on Sheveluch (Russia) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 23:8. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199808-300270



Sheveluch

Russia

56.653°N, 161.36°E; summit elev. 3283 m

All times are local (unless otherwise noted)


Seismicity was generally at background levels during 25 July-1 September. On 25 July a fumarolic plume rose 300 m above the summit and extended more than 15 km SE. The following day the plume varied between 200 and 400 m in height and extended 5 km to the SE. During a period of just over 3 hours on 26 July, a series of strong, shallow earthquakes accompanied by volcanic tremor was recorded. Tremor was also recorded on 9 August. On 15 August a plume rising to 250 m extended 5 km E. Clouds obscured the volcano throughout much of the reporting period.

Geological Summary. 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: Olga Chubarova, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia; Tom Miller, Alaska Volcano Observatory (AVO), a cooperative program of a) U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), b) Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and c) Alaska Division of Geological & Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.