From Miller and others (1998) 
: "The undissected stratovolcano of Amukta volcano composes most of nearly circular, 7.7-km-wide Amukta Island. The cone, about 5.8 km in basal diameter and topped by a 0.4 km wide summit crater, appears on synthetic-aperture radar imagery to be built on a 300+ meter high, east-west trending arcuate ridge. Extensions of that ridge on the southwest and east sides of the island indicate an older caldera approximately 6 km in diameter and open to the sea on the south side. No hot springs or fumaroles have been reported from Amukta. Sekora (1973, p. 29) 
reports the presence of a cinder cone near the northeastern shore of the island."