Report on Bezymianny (Russia) — August 1996
Bulletin of the Global Volcanism Network, vol. 21, no. 8 (August 1996)
Managing Editor: Richard Wunderman.
Bezymianny (Russia) Lava extrusion, rock avalanches, and increasing seismicity
Please cite this report as:
Global Volcanism Program, 1996. Report on Bezymianny (Russia). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 21:8. Smithsonian Institution. https://dx.doi.org/10.5479/si.GVP.BGVN199608-300250.
55.972°N, 160.595°E; summit elev. 2882 m
All times are local (unless otherwise noted)
Scientists doing fieldwork on 23-24 July observed up to six cold rock avalanches that were connected with extrusive block (obelisk) growth on the dome of the volcano. A number of local earthquakes were also recorded at the nearest seismic station (14 km away).
On 20-22 August a weak fumarolic cloud was observed. Seismicity at the volcano during 19-26 August was above background levels, and both the number and energy of earthquakes gradually increased. A viscous lava flow extruded from the top of the dome during 26-28 August and 31 August-1 September, but no ash explosions were observed.
Geologic Background. Prior to its noted 1955-56 eruption, Bezymianny had been considered extinct. The modern volcano, much smaller in size than its massive neighbors Kamen and Kliuchevskoi, was formed about 4700 years ago over a late-Pleistocene lava-dome complex and an ancestral edifice built about 11,000-7000 years ago. Three periods of intensified activity have occurred during the past 3000 years. The latest period, which was preceded by a 1000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of St. Helens in 1980, produced a large horseshoe-shaped crater that was formed by collapse of the summit and an associated lateral blast. Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater.
Information Contacts: Tom Miller, Alaska Volcano Observatory (AVO), 4200 University Drive, Anchorage, AK 99508-4667, USA; Vladimir Kirianov, Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanic Geology and Geochemistry, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia.