Report on Bezymianny (Russia) — 27 April-3 May 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
27 April-3 May 2011
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2011. Report on Bezymianny (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 27 April-3 May 2011. 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 22-29 April a bright thermal anomaly on Bezymianny was detected in satellite imagery. A gas-and-steam plume that drifted 27 km NW was also detected on 22 April. According to ground-based observations, gas-and-steam activity was noted during 22 and 24-25 April. The Aviation Color Code was lowered to Yellow.
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.