Logo link to homepage

Report on Sheveluch (Russia) — September 2000


Sheveluch

Bulletin of the Global Volcanism Network, vol. 25, no. 9 (September 2000)
Managing Editor: Richard Wunderman.

Sheveluch (Russia) Low-frequency tremor; gas-and-ash explosions cause ash advisories

Please cite this report as:

Global Volcanism Program, 2000. Report on Sheveluch (Russia) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 25:9. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200009-300270



Sheveluch

Russia

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

All times are local (unless otherwise noted)


Volcanic ash advisory statements were issued to aviators for the 23 and 28 August eruptions at Shiveluch (BGVN 25:08), indicating that aircraft needed to ascend to a higher altitude or to navigate around the potentially dangerous ash clouds. The ash clouds on both dates were carried E or SE from the volcano at speeds of up to 93 km/hour, and drifted up to an altitude of ~10 km.

Volcanic unrest continued throughout September 2000, and a hazard status of Yellow was maintained. At 1417 on 2 September, seismic data indicated a possible short-lived gas-and-ash explosion. Estimates of cloud height based on seismicity suggested that the plume reached ~1,500 m. After this explosion, activity ceased until 6 September, when a fumarolic plume rose 200 m above the volcano.

The volcano remained quiet until 0715 on 13 September when seismic data indicated another gas-and-ash explosion. Following the explosion, strong spasmodic low-frequency tremor was recorded. Visual reports at 0800 from the residents of Kliuchi, 50 km SW of the summit crater, indicated that the ash plume rose 3,000 m above the dome and extended more than 10 km E. By 1000 the plume became ash-poor and decreased in height to 2,000 m. By 1130 the plume had diminished to only 200 m above the dome. Satellite imagery showed the ash cloud extending ~300 km E of Shiveluch by 1242. As a result of this activity, a volcanic ash advisory was issued. At 1530 the summit was obscured, but a fumarolic plume emerged from the E foot of the dome to a height of 100 m. The low-frequency tremor gradually decreased to background level by 1100 on 14 September.

On 17-18 and 20-21 September, gas-and-steam plumes with heights of 200-400 m were observed at the E end of the dome. Seismic activity was close to background levels, with some low-frequency tremor until 0249 on 18 September, when seismic data evidenced another gas-and-ash explosion. Plume height was estimated at ~1,700 m based on seismic data. On September 22-23 and 25-28, gas-and-steam plumes emanated from the E portion of the dome. Seismicity then decreased to background levels.

On 8 and 10 October, gas-and-steam plumes rose 200-400 m from the summit and extended 3-5 km to the east. On 9 October, weak fumarolic activity was observed. Weak continuous volcanic tremor was registered during 5-12 October. A gas-and-ash explosion was indicated by seismicity at 0318 on 10 October; cloud height based on seismic data was ~1,700 m. Intensive spasmodic low-frequency tremor was recorded until about 0400 following the explosive event. On 15 October, weak fumarolic activity was observed. The following day, a gas-and-steam plume rose 250 m above the dome. An episode of strong shallow seismic events during 0512-0532 on 14 October suggested a gas-and-ash explosion with a plume height of 4,200 m. Continuous weak volcanic tremor was recorded from 13-19 October. Shiveluch's hazard status remained at Yellow.

Geological Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka's largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. 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 occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. 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; Anchorage VAAC (Volcanic Ash Advisory Center), NOAA Alaska Aviation Weather Unit, 6930 Sand Lake Road, Anchorage, AK 99502-1845, USA (URL: http://www.alaska.net/ ~aawu/vaac.html); Tokyo VAAC, Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/).