Report on Bezymianny (Russia) — 19 April-25 April 2023
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 19 April-25 April 2023
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2023. Report on Bezymianny (Russia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 19 April-25 April 2023. 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 a daily thermal anomaly from continuing lava effusion at Bezymianny was identified in satellite images during 14-20 April. Gas-and-steam emissions were visible and occasional collapses from the growing lava dome produced avalanches of hot material. The Aviation Color Code was lowered to Yellow (the second lowest level on a four-color scale) on 20 April because activity had declined after the strong 7-8 April explosive eruption. Dates are based on UTC times; specific events are in local time where noted.
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.