On 24 March KVERT raised the Concern Color Code at Kliuchevskoi to Red (the highest level) due to an increase in seismic and volcanic activity. According to visual and video data, a gas-and-steam plume containing ash rose to ~7.5 km (24,600 ft) a.s.l. on 22 March, and ~8.5 km (~27,900 ft) a.s.l. on 23 March, extending NW. Ash fell in the town of Kluchi during 23-24 March. According to data from AMC Yelizovo, an ash plume that rose to ~7 km (~23,000 ft.) a.s.l. and extended 70-80 km (44-50 mi) to the NW was observed by pilots on 23 March.

During about 27-28 March seismic activity at Kliuchevskoi decreased, leading KVERT to reduce the Concern Color Code to Orange. According to visual and video data, a gas-and-steam plume containing some ash rose ~200 m above the crater (~16,500 ft a.s.l.) and extended W during 27-28 March.

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.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)