Paleotsunami Inundation of a Beach Ridge Plain: Cobble Ridge Overtopping and Interridge Valley Flooding in Seaside, Oregon, USA

Figure 4

West-east topographic profiles across the Seaside beach plain at selected locations: 12th Avenue, Broadway Avenue, Avenue N, and the Palmrose midden site. See Figure 2 for location positions in the Seaside beach plain. Vertical elevation 1–10 m is based on the NAVD88 datum. Vertical to horizontal exaggeration of profile scale is 40x. The interridge valleys of the Necanicum and Neawanna are particularly susceptible to tsunami flooding from (1) overtopping of the seawardmost beach ridges, and/or (2) sustained flow through the Necanicum Bay tidal inlet, north of 12th Avenue (Figure 2). Base image is from Google Earth.