Volcanology
The Kurile lake caldera was formed by two large volcanic explosions, one 41,500 radiocarbon years ago and the other around 6440 BC.
The huge amount of material ejected during the second explosion, comparable to some of the largest eruptions in recorded history, produced thick pyroclastic flow deposits around the countryside, and some ash fell more than 1000 km away on the Asian mainland.
The pyroclastic-flow deposit is about 100-m thick at a location on the Ozernaya River, 3 km west of Kurile Lake, forming a spectacular curtain of cliffs, known as Kuthiny Baty ("vertical standing boat") because of its erosionally fluted formation.
The explosion of around 6440 BC is given a score of 7, the second highest ranking on the Smithsonian Global Volcanism Program's Volcanic Explosivity Index, making it comparable to some of the largest eruptions in recorded history such as Santorini, Changbaishan, Crater Lake, Kikai and Tambora.
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