Report on Bezymianny (Russia) — February 1979
Scientific Event Alert Network Bulletin, vol. 4, no. 2 (February 1979)
Managing Editor: David Squires.
Bezymianny (Russia) Largest explosion since 1956 produces 0.2 km3 of ejecta
Please cite this report as:
Global Volcanism Program, 1979. Report on Bezymianny (Russia) (Squires, D., ed.). Scientific Event Alert Network Bulletin, 4:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN197902-300250.
55.972°N, 160.595°E; summit elev. 2882 m
All times are local (unless otherwise noted)
After a brief period of premonitory seismicity, a series of explosions from Bezymianny began at 1023 on 11 February. The explosions produced what was reported as an agglomerate flow about 10 km long and 10 m thick. They also deposited 2 cm of ash on a town several dozen km from the volcano, and destroyed part of the new cone. Lava flowed several hundred m down the NW flank. The volume of material erupted was about 0.2 km3.
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: N. Kozhemyaka, IVP; Tass; Sovetskaya Rossiya Radio, Moscow.