KVERT reported that activity at Bezymianny was significantly elevated during 0700-0830 on 17 October and was characterized by large collapses on the E flanks of the lava dome based on satellite and webcam images. These collapses generated hot avalanches of material and produced ash-and-gas plumes that rose as high as 3.5 km a.s.l. and drifted 15 km NE. At 1419 the Aviation Color Code was raised to Orange (the third level on a four-color scale). Lava extrusion continued at least through 1727 and ash plumes had drifted as far as 86 km NE. All times are local.

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 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.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)