|The central cone of the volcano almost completely fills the area of the second caldera, which is superimposed on the first caldera with some shift to the south. The first caldera has a diameter of 6-7 km, the second caldera is 3 km. The diameter of the base of the cone of the stratovolcano is 3 km, the width of its crater is more than 1 km. In all likelihood, the formation of a wide crater was caused by a westward blast that demolished the western part of the building. A pyroclastic flow descends from the crater to the northwest into the cavity of the ancient caldera. In the destroyed crater of the central cone, a rather well-preserved extrusive dome rises. Its peak reaches 888 m above sea level, or about 200 m above the bottom of the crater.
Горшков Г.С. Вулканизм Курильской островной дуги / Отв. ред. Рудич К.Н. 1967. 288 с.