|The central cone of the postglacial Sinarka volcano completely covers the ancient caldera and fills the adjacent valleys and troughs. The northwest slope of the cone is destroyed (by explosion or landslides), and a short and wide tongue of the lava flow descends along the pothole. A steep dark extrusive dome emerges from the crater, the agglomerate mantle of which almost completely covers the crest ridge and descends in many places along the slopes of the cone. The top of the dome is flat and covered with a chaotic pile of rocks.
1.5 km southwest of the Sinarka dome there is a second extrusive dome - Mount Zheltokamennaya, 898 m high, with a well-preserved shape. 1 km north of Sinarka there is a heavily destroyed formation surrounded by a powerful field of altered rocks. Apparently, this is another heavily destroyed dome. All three domes are timed
to the edges of the alleged large crater. The young cone and both domes are composed of two-pyroxene andesites with close composition.
Горшков Г.С. Вулканизм Курильской островной дуги / Отв. ред. Рудич К.Н. 1967. 288 с.