Kunashir is the southernmost island on the Kuril Island chain which is generally very high in volcanic activity because of it’s geological position. The island chain is located in the Pacific Ring of Fire, a horseshoe of natural disasters stretching from Mt. Saint Helens to Mount Fuji. The ring of fire is so geologically active because it is a meeting point where many plates interact.
In order to understand the action of plates and their destructive activity, one must understand plate tectonics. Tectonic plates are pieces of the earth’s crust that flow on the upper mantle, made up of semi-liquid molten rock, the plates flow because of heat currents rising and falling within the mantle. The currents heat up and rise to the outermost level, then they expand and cool, becoming denser than the heated rocks and sinking back down. All this action forms convection cells, as the cells circulate they move large amounts of the molten rock causing plates to shift. When these large plates collide the can create volcanoes such as the one found on Kunashir.
The Golovnin volcano was created by the Okhotsk plate, a continental plate, pushing the Pacific plate, and oceanic plate, underneath it, a process called subduction. As the pacific plate went under it released
water trapped inside it, this water made the melting point of the continental crust lower and so some magma rose. The magma melted away the surface of the earth and erupted forming a very steep volcano, however later the volcano caved in to itself and formed a rounded large circular volcano called a caldera.
The caldera is 4 by 5km wide and has a 1x2.5km lake within it, it has active solfataric areas and explosion craters. The temperature range within the caldera is between 36-100 degrees celsius.…