Monday, June 18, 2012

ESA ISS Astronaut Image: Alaid Volcano in the Kuril Islands

Alaid Volcano in the Kuril Islands of the Russian Federation is featured in this image photographed by an Expedition 31 crew member on the International Space Station.

The Kurils chain extends from the Kamchatka Peninsula to the islands of Japan, and contains numerous active volcanoes along its length.

Alaid is the highest (2,339 meters above sea level) volcano in the Kuril chain, as well as being the northernmost.

The textbook conic morphology of this stratovolcano is marred only by the summit crater, which is breached to the south (center) and highlighted by snow cover.

The volcano rises 3,000 meters directly from the floor of the Sea of Okhotsk, with the uppermost part of the volcanic edifice exposed as an island.

Much of the sea surface surrounding the volcano has a silver-gray appearance. This mirror-like appearance is due to sunglint, where light reflects off the sea surface and is scattered directly towards the observer onboard the space station.

Sunglint is largely absent from a zone directly to the west of the volcano, most likely due to surface wind or water current patterns that change the roughness—and light scattering properties—of the water surface in this area.

Volcanoes in the Kurils, and similar island arcs in the Pacific “ring of fire”, are fed by magma generated along the boundary between two tectonic plates, where one plate is being driven beneath the other (a process known as subduction).

Alaid Volcano has been historically active with the most recent confirmed explosive activity occurring in 1996.

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