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Report on Sheveluch (Russia) — 27 February-5 March 2002

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 27 February-5 March 2002
Managing Editor: Gari Mayberry

Please cite this report as:

Global Volcanism Program, 2002. Report on Sheveluch (Russia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 27 February-5 March 2002. Smithsonian Institution and US Geological Survey.

Volcano Profile |  Weekly Report (27 February-5 March 2002)


Sheveluch

Russia

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

All times are local (unless otherwise noted)


During 22 February-1 March seismic and volcanic activity remained high at Shiveluch; several steam-and-gas and ash-and-gas eruptions occurred, pyroclastic flows traveled down the volcano's flanks, and seismicity remained above background levels. The highest rising ash-and-gas clouds were produced from eruptions on 27 and 28 February, and 1 March; the clouds reached a height of ~2 km. During the week, pyroclastic flows traveled as far as 2 km down the SE side of the lava dome. Seismicity included earthquakes with magnitudes less than 2.3 at depths of 0-5 km, many local shallow seismic signals (from possible avalanches or weak gas-ash explosions), and episodes of weak intermittent volcanic tremor. On the 22nd and the 27th, 1-hour and 45-minute-long series, respectively, of shallow seismic events were registered that may have been associated with pyroclastic flows or gas-and-ash explosions. Thermal anomalies were visible on satellite imagery. The volcano remained at Color Concern Code Orange ("volcano is in eruption or eruption may occur at any time").

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.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)