News reports indicate that a volcano on Russia’s Kamchatka peninsula has begun erupting for the first time in almost four decades. Reports indicate that the Plosky Tolbachik volcano began erupting in late November with the appearance of a large crack, or fissure, in the volcano’s side. The area is relatively sparsely populated but The Daily Telegraph reported that a campsite was destroyed by a lava flow and that two towns in the area were affected by volcanic ash.
Kamchatka and the Pacific Ring of Fire
The Kamchatka peninsula, in Russia’s far east, is noted for its volcanoes: the Smithsonian Institute’s Global Volcanism Program lists 114 of these which are thought to have been active during the past 10,000 years (the Holocene period) and a glance at the program’s map shows them concentrated on the spine and the east coast of the peninsula.
Kamchatka is part of the so-called Pacific Ring of Fire, a belt of seismic and volcanic activity which broadly surrounds the Pacific Ocean and marks the margins of some of the Earth’s major tectonic plates. Like most of the planet’s volcanoes, Kamchatka’s are associated with the subduction of one plate beneath another – a process which is also responsible for some of the world’s major earthquakes.
Off the coast of Kamchatka the Pacific plate is subducted beneath the Eurasian plate. As the crust descends it is subjected to increasingly high temperatures and melts: the hot, buoyant rock rises and reaches the surface in the form of a volcano. These volcanic chains (or volcanic fronts) are typical of subduction zones, occurring within the overlying plate at a distance determined by the angle of subduction and parallel to the plate boundary.
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