Report on Bezymianny (Russia) — 29 February-6 March 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
29 February-6 March 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Bezymianny (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 29 February-6 March 2012. Smithsonian Institution and US Geological Survey.
55.972°N, 160.595°E; summit elev. 2882 m
All times are local (unless otherwise noted)
KVERT reported that during 24 February-2 March seismic activity at Bezymianny remained elevated, with about 7-19 weak events registered daily. A thermal anomaly was detected in satellite images. Gas-and-steam activity was observed on 26 February; clouds obscured the volcano on the other days. One short volcanic tremor episode was detected on 29 February. About 40 seismic events were detected on 1 March and, according to satellite data analysis, the size and brightness of a thermal anomaly abruptly increased on 2 March. The Aviation Color Code was raised to Red. During 2-5 March there were 25-40 weak seismic events detected; cloud cover prevented observations of the volcano.
Geological Summary. The modern Bezymianny, much smaller than its massive neighbors Kamen and Kliuchevskoi on the Kamchatka Peninsula, was formed about 4,700 years ago over a late-Pleistocene lava-dome complex and an ancestral edifice built about 11,000-7,000 years ago. Three periods of intensified activity have occurred during the past 3,000 years. The latest period, which was preceded by a 1,000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of St. Helens in 1980, produced a large open 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.