KVERT reported that Strombolian and sometimes Vulcanian activity at Klyuchevskoy continued during 15-22 January and lava advanced down the Kozyrevsky drainage on the S flank and the Apakhonchich drainage on the SE flank. A large bright thermal anomaly was identified daily in satellite images. Steam-and-gas plumes with some ash rose to 6 km (19,700 ft) a.s.l. and drifted 200 km in multiple directions. A notable eruptive event on 18 January generated an ash plume that rose as high as 7.5 km (24,600 ft) a.s.l. and drifted 500 km W. Ashfall (1 cm thick) was reported in Kozyrevsk. On 24 January collapses from the lava flow at about 2,200 elevation sent large amounts of material and pyroclastic flows down the Apakhonchich drainage. KVERT estimated that the ash plumes from the event rose to 8.5 km (27,900 ft) a.s.l. The Tokyo VAAC stated that ash plumes rose as high as 10.4 km (34,000 ft) a.s.l. and drifted W on the same day. The Aviation Color Code remined at Orange (the second highest level on a four-color scale).

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)