BackgroundMaly Semiachik is a compound stratovolcano located in a 10-km-wide caldera within the 15 x 20 km mid-Pleistocene Stena-Soboliny caldera. Following construction during the late Pleistocene of the Paleo-Semiachik volcano beginning about 20,000 years before present (BP), activity migrated to the SW, forming Meso-Semiachik (about 11,000-9000 BP) and Ceno-Semiachik (about 8000 BP to the present). An initial stage lasting about 3500 years was dominantly explosive, constructing the present cone. A second stage beginning about 4400 years ago was marked by alternating constructive and destructive processes during which the volcano was destroyed by major explosions and then reconstructed. A crater lake fills the historically active Troitsky Crater, which formed during a large explosive eruption about 400 years ago.
Smithsonian / GVP volcano information
Maly Semiachik Photos
A turquoise acid crater lake occupies the summit crater of Maly Semiachik. It is one of the most acid in the world. (Photo: Tom Pfeiffer)
View towards Maly Semiachik volcano. (Photo: Tom Pfeiffer)
Next announcement by the stewardess: Maly Semiachik volcano. (Photo: Tom Pfeiffer)
See also: Sentinel hub | Landsat 8 | NASA FIRMS