Report on Sheveluch (Russia) — December 2001
Bulletin of the Global Volcanism Network, vol. 26, no. 12 (December 2001)
Managing Editor: Richard Wunderman.
Sheveluch (Russia) Through January 2002, elevated seismicity, and an unstable, growing lava dome
Please cite this report as:
Global Volcanism Program, 2001. Report on Sheveluch (Russia) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 26:12. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200112-300270.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
In mid-July 2001, the level of concern for Shiveluch was raised from Yellow to Orange (BGVN 26:08) and remained at that level until the end of November 2001 when it was returned to Yellow. During a very active period, 30 September through 1 October, the level of concern was set to Red. The level of concern remained at Yellow through early January 2002, rising briefly to Orange in mid-January and returning to Yellow at the end of the report period, 25 January 2002.
During mid-July through at least 25 January 2002, seismicity was above background levels. The lava dome, now with a summit at ~2,500 m, continued to grow. Typical activities throughout the period included explosions, some producing pyroclastic flows, ash and/or gas-and-steam plumes typically rising 1-2 km (3,500-4,500 m altitude) above the dome, and localized ash falls. Plumes drifted in various directions depending upon local wind conditions and extended from several to as much as 80 km from the volcano. As many as 60 or more earthquakes over M 1.7 (including some over M 2.0) occurred weekly, with many other weak, shallow earthquakes occurring within the volcano's edifice. Other local, shallow seismic events (possible collapses, avalanches, weak gas-ash explosions), and episodes of weak, volcanic tremor also were registered. In mid-January the earthquake rate decreased but the energy of individual events increased (maximum magnitude, 2.7).
The AVHRR satellite images of the active dome area showed thermal anomalies almost daily throughout the period. Anomalies ranged from 1 to 10 pixels in size with maximum temperatures from a few degrees C to 49°C on numerous occasions. Background temperatures typically ranged from -14 to -29° C.
Activities from the end of August to late-January 2002 include visual reports on 4 September of a gas-and-steam plume rising 1,200 m above the dome and extending 10 km E, and a pyroclastic flow ~1 km long later that day. On 11 September, several hot avalanches from the summit of the dome were observed. An explosive eruption began at 1323 on 30 September and, at 2010, another explosion sent an ash plume 9,000 m above the dome. A small circular cloud ~25 km in diameter located directly over the volcano was reported later. On 1 October, ash plumes were observed to be as high as 7,500 m above the dome with localized ashfall thicknesses in the millimeter range. This eruption was the beginning of a very active period that extended into the first week of October, e.g., eleven M 2 and nine M 1.7 earthquakes were registered during 1-4 October. On 19 November a 10-pixel thermal anomaly was observed with temperatures ranging from 0 to 49°C. A steam plume observed on 7 January extended ~100 km SE. On 14 January, continuous rock avalanches were reported by observers in Klyuchi town. Gas-and-steam plumes that week rose 1,000-1,500 m above the dome and extended 10 km SE. Seismicity decreased during 19-25 January compared to the previous week. Several gas-and-steam plumes were observed, one extending 75 km to the SE on 21 January. Thermal anomalies continued but no ash was detected in any image.
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: 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.