The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that eruptive activity at Klyuchevskoy’s summit crater continued during 30 July-5 August. Satellite data showed a strong thermal anomaly at the volcano all week. Since 30 July a lava flow has been moving down the WSW flank, accompanied by phreatic explosions. Satellite data at 2315 on 1 August showed an ash plume extending for 150 km to the SE. Ash seen in satellite imagery at 0613 on 2 August was rising up to 7-8 km (23,000-26,200 ft) a.s.l. and drifting 50 km E. Additional satellite data from 4 August at 0432 showed ash reaching up to 7.5 km (24,600 ft) a.s.l. and extending for 50 km to the NE. Two lava flows were reported on 4 August effusing down the W and SE flanks, with ash rising up to 7 km (23,000 ft) a.s.l. and drifting for 600 km to the SE. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates and times are provided in Coordinated Universal Time (UTC); specific events are indicated in local time where specified.

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)