Little Sitkin geologic map from USGS Bulletin 1028-H: Snyder, G. L., 1959, Geology of Little Sitkin Island, Alaska: in Investigations of Alaskan volcanoes, U.S. Geological Survey Bulletin B 1028-H, p. 169-210, 1 plate, scale 1:20,000.
Credit: Image courtesy of AVO/USGS.