Report on Klyuchevskoy (Russia) — July 1999
Bulletin of the Global Volcanism Network, vol. 24, no. 7 (July 1999)
Managing Editor: Richard Wunderman.
Klyuchevskoy (Russia) May-August seismicity weak; traces of ash in emissions
Please cite this report as:
Global Volcanism Program, 1999. Report on Klyuchevskoy (Russia). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 24:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199907-300260.
56.056°N, 160.642°E; summit elev. 4754 m
All times are local (unless otherwise noted)
During the period from 17 May to 9 August 1999, seismicity at the volcano was generally at or below background levels. Tremors and shallow earthquakes were registered occasionally, and earthquake hypocenters were concentrated near the summit crater. Gas-and-steam plumes containing ash occurred weekly, rising from a few hundred meters to as high as 2 km above the crater. Ash in these plumes dispersed in various directions to distances from 1 to 15 km (the latter on 18 June and extending to the S). On numerous days during this period, the volcano was obscured by clouds.
In one interval, starting on the afternoon of 28 May, a series of small (M 0.5) shallow earthquakes and tremor was recorded. Seismicity increased markedly on 30 May with a series of shallow earthquakes (M <2). This declined at 1122 on 30 May and remained at background levels. During the first half of July and again on 21 and 25 July, weak fumarolic activity was again observed at the summit.
During 12-18 July, seismicity rose above background as tremor and shallow earthquakes registered. On the morning of 12 July a gas-and-steam plume rose 200 m above the crater and extended up to 4 km. In the evening, a gas-and-steam plume with a mixture of light brown ash rose 1.5 to 2 km above the crater extending as much as ~5 km downwind.
Geologic Background. Klyuchevskoy (also spelled Kliuchevskoi) is Kamchatka's highest and most active volcano. Since its origin about 6000 years ago, the beautifully symmetrical, 4835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of sharp-peaked Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during the past roughly 3000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 m and 3600 m elevation. The morphology of the 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters.
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.