Mt. Adams is an active andesitic stratovolcano. Most of the main cone is younger than 220,000 years. Post glacial eruptions and weak fumaroles suggest that Mt. Adams may erupt again. East Crater is a shield volcano along the Indian Heaven volcanic field that erupted basalt during the Pleistocene epoch.
Hildreth, W., and Fierstein, J., 1985, Mount Adams: Eruptive history of an andesite-dacite stratovolcano at the focus of a fundamentally basaltic field: U.S. Geological Survey Open-file Report 85-521, 44-50. Hildreth, W., and Fierstein, J., in preparation, Geologic map of the Mount Adams volcanic field: U.S. Geological Survey. Wood, C.A., and Kienle, J., 1993, Volcanoes of North America: Cambridge University Press, New York, 354 p.
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