KVERT reported that during 30 January-6 February a Strombolian and Vulcanian eruption at Klyuchevskoy continued. Incandescence at the summit was visible and bombs were ejected 200-300 m above the crater. Explosions generated ash plumes that rose to altitudes of 5-6 km (16,400-19,700 ft) a.s.l.; ashfall was reported in Klyuchi Village (30 km NNE) on 5 February. A lava flow effused onto the E flank. Satellite images showed a daily, big, bright thermal anomaly over the volcano, and ash-and-gas plumes drifting in multiple directions at altitudes of 5.5-6 km (18,000-19,700 ft) a.s.l. During 4-5 February ash plumes drifted about 1,000 km NW and N. The Aviation Color Code remained at Orange.

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)