4. Tolbachik complex volcano.The Tolbachik massif is composed of two overlapping, but morphologically dissimilar volcanoes. The flat-topped Plosky Tolbachik shield volcano with its nested Hawaiian-type calderas up to 3 km in diameter is located east (right) of the older and higher sharp-topped Ostry Tolbachik stratovolcano. The 1975-76 eruption from the summit and SSW-flank fissures was the largest historical basaltic eruption in Kamchatka. Photo by Oleg Volynets, Institute of Volcanology, Petropavlovsk; data from Smithsonian Global Volcanism Program.