Report on Bezymianny (Russia) — 23 June-29 June 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
23 June-29 June 2004
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2004. Report on Bezymianny (Russia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 23 June-29 June 2004. Smithsonian Institution and US Geological Survey.
55.972°N, 160.595°E; summit elev. 2882 m
All times are local (unless otherwise noted)
An eruption at Bezymianny produced an ash cloud that during 18-19 June extended more than 1,000 km E and SE from the volcano and possible ash deposits extended 190 km SE from the lava dome. Seismicity at Bezymianny did not exceed background levels during 20-23 June. The Concern Color Code at Bezymianny was reduced from Orange to Yellow around 25 June.
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.