Report on Bezymianny (Russia) — 1 November-7 November 2000
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 1 November-7 November 2000
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2000. Report on Bezymianny (Russia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 1 November-7 November 2000. 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 an increase in seismicity began at Bezymianny on 30 October, reaching its highest level during 0320 to 0400 on 2 November. At 0626 AVHHR imagery showed that an ash plume from the volcano reached ~6.5 km a.s.l., initially extending to 50 km W of the volcano, then 130 km to the SW. At 1200 seismicity began to decrease. In addition to the AVHHR imagery, the Tokyo VAAC detected the ash cloud in GMS-5 imagery until 2332. Small ash clouds were visible on AVHRR imagery during 2 and 3 November. KVERT lowered the Level of Concern Color Code at the volcano from Orange to Yellow.
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.