三日月山

The northernmost volcano on Simushir Island, Uratman consists of a 7.5-km-wide Pleistocene caldera with walls that rise 450 m above a 250-m-deep caldera bay. A narrow gap in the northern rim provides ocean access into Brouton Bay, which fills the NW half of the caldera. The andesitic central cone grew during the Holocene in the SE part of the caldera. Two cinder cones are located along the N flank of Uratman, and a lava dome was formed on its NW flank along Brouton Bay. No recorded eruptions are known.