KVERT reported that fumarolic activity from Kliuchevskoi was observed during 3-10 April. Satellite imagery indicated a thermal anomaly over the volcano on 5 and 6 April, and weak volcanic tremor was detected during 5-8 April. Based on analysis of satellite imagery, the Tokyo VAAC reported that a possible eruption on 9 April produced a plume that rose to an altitude of 4.9 km (16,000 ft) a.s.l. and drifted NE. Imagery later indicated that any ash that may have been present had dissipated. On 11 April, imagery again indicated a possible eruption; any resultant ash plumes had dissipated by a few hours later. The Level of Concern Color remained at 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.

Sources: Tokyo Volcanic Ash Advisory Center (VAAC), Kamchatkan Volcanic Eruption Response Team (KVERT)