KVERT reported that seismic activity at Kliuchevskoi was slightly above background levels during 26-27 November, and did not exceed background levels during 28 November-3 December. Satellite imagery showed gas-and-ash plumes drifting 430 km N and NE during 26-29 November and a weak thermal anomaly over the crater on 26, 28, and 29 November. Ash plumes were seen rising to an altitude of 6.3 km (20,700 ft) a.s.l. on 26 and 29 November and 1 December. Ash fell in Kozyrevsk (about 50 km W) on 27 November and in Klyuchi (30 km NNE) on 28 November. Strombolian activity was observed on 1 and 2 December. The Aviation Color Code level remained at Orange.

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)