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.
A steaming lava dome fills much of the large horseshoe-shaped crater cutting the ESE side of Bezymianny volcano in this late-1980s view from the SE. The crater was formed during a dramatic eruption in 1955-56, which was similar to that of Mount St. Helens in 1980. Prior to this eruption, Bezymianny volcano had been considered extinct. Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater.
Photo by Yuri Doubik (Institute of Volcanology, Petropavlovsk).
Last updated 2019-12-17 19:00:04