Monday 22 October 2012

Volcanism on Mount Kliuchevskoi.

The Kamchatka Peninsula in the Russian Far East lies on the eastern margin of the Okhotsk Plate, close to its margin with the Pacific and North American Plates, both of which are being subducted beneath it. As the two plates pass under the peninsula they are partially melted by the friction and the heat of the planets interior. Some of this melted material then rises through the overlying Okhotsk Plate, fueling volcanism across Kamchatka. There are over 150 volcanoes on the peninsula in total, 29 of which are considered to be currently active. The largest and most active of these is Mount Kliuchevskoi (Klyuchevskaya Sopka), in the central part of the peninsula, which rises 4750 m above sea level and has been active more-or-less constantly since 1697.

An ash plume rising from Mount Kluichevskoi. Газета Киевская.

The last significant eruptive episode on Kluichevskoi was in November 2011, when the volcano threw an eruptive plume 6.7 km into the atmosphere, since when it has been relatively quiet. On 21 June 2012 the Kamchatkan Volcanic Eruption Response Team recorded seismic activity (tremors) beneath Kluichevskoi, which continued and grew over the following weeks. Such activity beneath volcanoes is significant as it often indicates new magma moving into chambers beneath them. On 1 September a weak thermal anomaly (hotspot) was also detected, which persisted through the next six weeks, during which time the seismic activity also continued to grow in intensity. On 14 October the mountain began to erupt again, producing a series of small Strombolian eruptions (intermittent explosions and fountains of lava). This continued overnight till 15 October, since when the summit of the volcano has been hidden by cloud. The aviation alert in the area remains high.

Top. Topographic map showing the area around Kluichevskoi. Bottom. Wider map of the peninsula showing the location of Kluichevskoi (A). Google Maps.

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