Urataman is the northernmost of the 6 volcanoes on Simushir Island, Kuriles. It has an impressive 7.5-km-wide caldera which forms the NE tip of the island. Its caldera walls rise 450 m above a 250-m-deep bay. Sea water enters the caldera through a narrow gap in the northern rim and creates the half-moon-shaped Brouton Bay, corresponding to about half the surface of the caldera. Within the past 10,000 years and after the formation of the caldera, a large new central cone, the andesitic Urataman volcano proper, has grown in the SE part of the caldera. Besides the central vent, there are 2 cinder cones on the northern and a lava dome on the NW flank of Urataman volcano.