八幡平

Hachimantai was constructed from widely scattered vents during the Pleistocene and is capped with andesitic lavas from vents in the center of the complex. The summit forms an undulating plateau surrounded by steep slopes. Circular craters are located near Komonomore and Mokkodake in the center of the plateau. The craters are youthful looking, but have not been dated. Hayakawa (1996, pers. comm.) considered Hachimantai to be of possible Holocene age. No historical eruptions have been recorded, but active solfataras are found on the western and southern flanks.