Figure 12.17
GEO-GRAPHIC: Continental-oceanic convergent plate boundary. (A) Continental volcanic arcs are formed along the margin of a continent where oceanic crust is being subducted. (B) The Cascade Range in the Pacific Northwest of the United States and southern Canada is a continental volcanic arc. It is the result of the Juan de Fuca plate subducting beneath the North American plate (the black line with triangles shows the plate boundary and the direction of plate movement). The mid-ocean ridge separating the Pacific plate from the Juan de Fuca plate is also shown in this map. Mount St. Helens (in the foreground of the photo) and Mount Rainier are among the 18 active volcanoes in the Cascades.(photo, © Gary Braasch/Corbis)