Karymsky, the most active volcano of  Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano that has been in a vigorous phase of activity for about 500 years. Much of the cone is surrounded by lava flows no older than 200 years. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater.
The cone has been constructed during the past 2000 years within a 5-km-wide caldera that formed about 9,000 year ago within a complex system of overlapping calderas. The caldera cuts the south side of the older Dvor volcano and is located outside the north margin of a large, still older caldera (the mid-Pleistocene Polovinka caldera), which contains the smaller Akademia Nauk and Odnoboky calderas.
Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, which is located immediately south of Karymsky volcano.
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