Report on Bezymianny (Russia) — 2 February-8 February 2011
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
2 February-8 February 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, 2 February-8 February 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 28 January-4 February seismicity from Bezymianny did not exceed background levels, however weak volcanic earthquakes were detected. A thermal anomaly over the volcano was observed daily in satellite imagery. Gas and steam activity was observed during 30-31 January and 1-3 February; cloud cover prevented observations on the other days. The Aviation Color Code level remained at Yellow.
Based on information from the Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 4 February an ash plume rose to an altitude of 4.6 km (15,000 ft) a.s.l. drifted NE.
Geological Summary. 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.