Kasatochi volcano as seen from 17,000 feet ASL.

Kasatochi Island, like Gareloi, Bogoslof, and several other volcanoes in the western Aleutian arc, represents the emergent summit of a predominantly submarine volcano. The island consists of a single, undissected cone with a central lake-filled crater about 0.75 km in diameter. A maximum height of 314 m is on the southern crater rim; elevation of the lake is less than about 60 m.