Based on seismic data from the Kamchatka Branch of Geophysical Services (KBGS; Russian Academy of Sciences), KVERT reported that a Strombolian eruption from Kliuchevskoi began at 1830 on 15 August. Video images recorded incandescence from the crater that night, and gas-and-steam plumes containing minor amounts of ash rising as high as 6 km (19,700 ft) a.s.l. and drifting NE during 15-16 August. Satellite images detected a large, bright thermal anomaly during 15-16 August. The Aviation Color Code was raised to Yellow, the second lowest of a four-color scale. Gas-and-steam plumes containing minor amounts of ash rose to an altitude of 5.5 km (18,000 ft) a.s.l. during 16-17 August. Incandescence from the crater at night and a thermal anomaly in satellite images continued to be reported during 17-19 August.

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)