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Mapped Overland Distance Of Paleotsunami High-Velocity Inundation N Back-Barrier Wetlands Of The Central Cascadia Margin, U.S.A, Robert B. Schlichting, Curt D. Peterson

Geology Faculty Publications and Presentations

Investigations of back-barrier, open-coastal plain settings have been used to establish minimum inundation distances of prehistoric tsunamis produced by great subduction zone earthquakes in the central Cascadia margin. Distinctive sand sheets were characterized at four localities within the central Cascadia margin, a shoreline distance of about 250 km. The sand sheets vary in thickness from 0.2 to 25 cm. They thin in the landward direction and consist of well-sorted beach sand that fines upsection. Many of the sand sheets include capping layers of organic-rich detritus, as well as assimilated mud rip-up clasts and soil litter. Marine diatoms and bromine (i.e., …