A group of basaltic cinder cones lies south of Bakening volcano, west of the Srednaya Avacha (Middle Avacha) river valley. They are part of a broad zone of regional late Pleistocene to Holocene basaltic volcanism west of the Eastern volcanic zone of Kamchatka that extends from the Kostakan Lake area to the south. Several of the cinder cones are breached by lava flows, some of which extend into the Srednaya Avacha valley. The highest-elevation vent, Zmeya crater, was constructed within a landslide scarp. An unnamed maar is located about 2 km S of Kostakan Lake. Eruptions have occurred during two time periods, between about 11,000 to 7,000 years ago and between about 1,200 and 600 years ago.