KVERT reported that during 29 October-3 November seismic activity at Kliuchevskoi was above background levels and Strombolian activity was observed. Satellite imagery analyses showed a thermal anomaly over the volcano and ash plumes that drifted 480 km SE. Vulcanian activity produced ash plumes that rose to an altitude of 7 km (23,000 ft) a.s.l. during 31 October and 1-4 November. Seismicity sharply decreased on 4 November, and only gas-and-steam activity was observed. On 9 November, KVERT reported that the eruption that began in August 2009 had finished on 4 November and that seismicity had continued to decrease. The Aviation Color Code level was lowered to Yellow.

Geological Summary. Klyuchevskoy is the highest and most active volcano on the Kamchatka Peninsula. Since its origin about 6,000 years ago, this symmetrical, basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during approximately the past 3,000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 and 3,600 m elevation. Eruptions recorded since the late 17th century have resulted in frequent changes to the morphology of the 700-m-wide summit crater. These eruptions over the past 400 years have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)