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

Figure 19

Map of tsunami inundation in Seaside, Oregon, for three events including historical farfield tsunami in 1964 (small arrows), the last Cascadia nearfield tsunami at AD 1700 (dark gray), and a larger Cascadia tsunami from rupture event #3 at 1.3 ka (light gray). The historical 1964 inundation was localized to modern tidal inlet (small arrows) and intertidal channels. The AD 1700 inundation entered a paleo-Necanicum tidal inlet to flood the interior beach ridge plain (medium arrows). The larger Cascadia paleotsunami at 1.3 ka flooded the entire beach ridge plain, including the highest cobble beach ridges on either side of the tidal inlet (large arrows).