|The Berg volcano is a stratovolcano with a wide caldera with a diameter of about 2 km at the top, in which there is a low extrusive dome with a diameter of 700 m and a height of 200 - 250 m (approximately 950 m above sea level). The flat top of the dome is covered with a powerful layer of pyroclastics, through which separate needles and ridges of the rocks protrude. In the southern part of the dome is a deep explosive crater. Another, more recent-looking crater filled with solfataras is located in the northwestern part of the dome. In the eastern part of this crater there is a deep explosive well with a diameter of about 100 m. Two small lava flows of very viscous lava descend north of the dome. One of the flows flowing from under the dome is older, a young lava flow descends from the top of the dome (Горшков, 1967).
Горшков Г.С. Вулканизм Курильской островной дуги / Отв. ред. Рудич К.Н. М.: Наука. 1967. 288 с.