Vilyuchik, also known as Uilyuchinsky, is a steep-sided Holocene stratovolcano that forms a prominent landmark south of Avachinsky Bay. It is seen here from the south, between Mutnovsky and Gorely volcanoes. Deep erosional gulleys dissect the flanks of the 2173-m-high volcano. Lava domes and young basaltic cinder cones were constructed at its base. It last erupted during the first half of the Holocene. Photo by Phil Austin, University of Southern Florida, 1992 (courtesy of Pavel Kepezhinskas).