Report on Klyuchevskoy (Russia) — 16 April-22 April 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 April-22 April 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Klyuchevskoy (Russia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 16 April-22 April 2003. Smithsonian Institution and US Geological Survey.
56.056°N, 160.642°E; summit elev. 4754 m
All times are local (unless otherwise noted)
A moderate vulcanian eruption of Kliuchevskoi began 15 April; it continued through at least 16 April. The eruption was preceded by above-background seismicity, and on 15 April there were ~70 earthquakes per day at ~30-km depth. Instruments registered continuous spasmodic volcanic tremor (up to 4.0 µm/second) and numerous weak shallow earthquakes. According to observers in Klyuchi, on 15 April a series of ash plumes rose up to 300 m above the crater and extended for 10 km. According to satellite data, on 16 April a thin, 175-km-long plume headed E. Observations on 17 April disclosed a zone of ash deposits extending ESE for 20 km from the crater. The Concern Color Code remained at Yellow.
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.