The mountain 's caldera was created in 946 by the colossal ( VEI 7 ) " Millennium " or " Tianchi " eruption , one of the most violent eruptions in the last 5,000 years , comparable to the 180 AD eruption of Lake Taupo and the 1815 eruption of Mount Tambora . The eruption , whose tephra has been found in the southern part of Hokkaidō , Japan , and as far away as Greenland , destroyed much of the volcano 's summit , leaving a caldera that today is filled by Heaven Lake
180 AD eruption of Lake Taupo
Hatepe eruption
Paektu Mountain