KVERT reported that the Strombolian eruption at Klyuchevskoy continued during 11-16 October and fed lava flows the descended the Apakhonchichsky drainage on the SE flank. Activity was notable during 11-12 October, characterized by the presence of ash in gas-and-steam plumes and an increase in the lava effusion rate. KVERT raised the Aviation Color Code to Orange (the third level on a four-color scale) as a result. According to observers at the Kamchatka Volcanological Station, lava effusion was almost continuous and incandescent material was ejected as high as 300 m above the crater rim. On 16 October lava on the SE flank melted snow and ice, causing phreatic explosions and large collapses of material from the margins of the flow. Dates and times are in UTC; specific events are in local time where noted.

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.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Kamchatka Volcanological Station