Figure 8b: Modern erosion scarp (3-4 m in height) that extends several hundred meters in length south of the Grays Harbor South Jetty. Small erosion scarps (1-2 m height) have also developed in adjacent to the Willapa Bay mouth, and in the Clatsop subcell, possibly reflecting diminishing sand supply at ‘hot spots’ near jetties or tidal inlets (Kaminsky et al., 1999). By comparison, catastrophic beach retreat from coseismic subsidence should result in system wide retreat of several hundred meters (Peterson et al., 2000). The frequency of such catastrophic events should be low (recurrence intervals of centuries). This modern-analog scarp has produced a heavy-mineral lag (placer deposit not shown in photograph) up to 10 cm in thickness, and several hundred meters in length between the beach toe and the foot of the scarp. Photograph view north.