The Kurile Lake caldera forming eruption, also known as KO, occurred in 6460-6414 BC. It is the largest known Holocene eruption in Kamchatka. Tephra from this eruption has been found in southern Kamchatka and also Magadan in Asia. The total volume of the Kurile Lake caldera forming eruption is about , corresponding to a volcanic explosivity index of 7 and comparable to the 1815 eruption of Tambora. Other volcanoes with such large eruptions during the Holocene include Baitoushan, Crater Lake and Kikai. The volume of the Kurile Lake eruption may have exceeded that of the Tambora eruption.