Tolbachik is a basaltic volcanic massif lying at the southern end of the Kliuchevskoi group in Kamchatka, Russia. It comprises two overlapping cones: Plosky Tolbachik, a Holocene shield volcano extending to 3 km in diameter; and the older (Pleistocene) Ostry Tolbachik, a sharp-topped stratovolcano reaching some 3,700 m in height.
Lava flows on the summit of Plosky Tolbachik. Photo credit: Lena Melekhova