|The central structure of the volcano Brat Chirpoev is located on the northwestern part of the Island, and consists of a large number of closely merged cones and craters. All of them are located along an arc of a circle, reflecting to some extent the outlines of the ancient caldera with a diameter of about 4 - 5 km. The extreme southwestern cone - actually Brat Chirpoev - has the largest dimensions and a summit crater with a diameter of about 250 m in the form of a deep funnel. The slopes of the cone are covered with a continuous cloak of cherry-red slag, lava flows are exposed only in sections of rocks. A deep and wide pothole descends along the western slope from the crater to the seashore. The lavas and slags of Brat Chirpoev volcano are olivine-pyroxene basalt. Eruptions of this volcano in historical time are not recorded [Горшков, 1967].
Горшков Г.С. Вулканизм Курильской островной дуги / Отв. ред. Рудич К.Н. М.: Наука. 1967. 288 с.