KVERT reported that during 30 April-7 May seismic activity from Kliuchevskoi was above background levels. Ground observations were prevented due to meteorological cloud cover. Satellite imagery revealed a large daily thermal anomaly from the volcano. Ash plumes drifted 125 km N on 2 May and 70 km W at an altitude of 5.5 km (18,000 ft) a.s.l. on 3 May. Gas-and-steam plumes drifted 55 km W and SW both days. Based on information from KEMSD, the Tokyo VAAC reported that on 10 May an eruption produced a plume that rose to an altitude of 6.1 km (20,000 ft) a.s.l. The Aviation Color Code level remained at Orange.

Geological Summary. Klyuchevskoy (also spelled Kliuchevskoi) is Kamchatka's highest and most active volcano. Since its origin about 6000 years ago, the beautifully symmetrical, 4835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of sharp-peaked Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during the past roughly 3000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 m and 3600 m elevation. The morphology of the 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions 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)