Figure 15. Location map of the Aleutian arc (see Nye et al., 1998). Historically active volcanoes are shown as shaded circles (Wood and Kienle, 1990), while the active volcanoes analyzed in this study are labeled. Volcanoes are subdivided on the basis of geographic position into intraoceanic (Aleutians sensu stricto) and continental (Alaskan). Convergence vectors and rates of subduction of the Pacific plate beneath the North American plate (DeMets et al., 1994) and the positions of the Rat, Adak, and Amlia fracture zones on the down-going plate are shown (Geist et al., 1988), along with the positions of DSDP sites 183 and 178 (Creager et al., 1973). Faults in mainland Alaska are shown as bold lines and contours are in meters below sea level.