KVERT reported that a Strombolian eruption began at Klyuchevskoy on 1 January; bombs were ejected 300-400 m above the crater. On 10 January strong gas-and-steam emissions containing ash were recorded by the webcam. Video images also indicated a possible lava flow on the S flank. The Aviation Color Code was raised to Orange. Strombolian and Vulcanian activity continued during 11-12 January, and explosions generated ash plumes that rose 5-7 km (16,400-23,000 ft) a.s.l. Satellite images on 11 January showed a 12.5-km-wide, 36.8-km-long ash plume drifting at an altitude of 5 km (16,400 ft) a.s.l. On 12 January an ash plume rose to an altitude of 5.5 km (18,000 ft) a.s.l. and drifted 35 km.

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)