Sponsor
Portland State University. Department of Geology
First Advisor
Curt D. Peterson
Term of Graduation
Spring 2000
Date of Publication
5-18-2000
Document Type
Thesis
Degree Name
Master of Science (M.S.) in Geology
Department
Geology
Language
English
Subjects
Stratigraphic geology -- Holocene, Floods -- Oregon, Floods -- Washington (State), Tsunamis -- Oregon, Tsunamis -- Washington (State)
DOI
10.15760/etd.5246
Physical Description
1 online resource (vi, 166 pages)
Abstract
Mapping and stratigraphic investigations of back barrier, open-coastal plain sites have been used to establish minimum inundation distances and wave heights of tsunami produced by great subduction zone earthquakes in the central Cascadia margin. Cascadia tsunami deposits have been reported for many coseismic subsidence events in bay marsh settings where tidal-channel features focus tsunami energy. Variable magnitude (8.5±0.5 Mw), frequency (500±300 yr recurrence), and rupture geometry produce widely varying computer model outcomes for Cascadia tsunami inundation. The results presented in this thesis provide specific quantitative data regarding tsunami inundation at the open coast.
Anomalous sand sheets that have been characterized consist of well-sorted beach sand that fine up-section. The thickness of the deposits vary from 45 cm to 0.2 cm, and thin in the landward direction. Many of the sand layers include detrital caps. One to three detritus and mud lamina are intra-layered in the deposits. Marine diatoms and bromine, a marine tracer, increase in concentration at each of the sand layers.
Rights
In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
Persistent Identifier
https://archives.pdx.edu/ds/psu/19071
Recommended Citation
Schlichting, Robert B., "Establishing the Inundation Distance and Overtopping Height of Paleotsunami from the Late-Holocene Geologic Record at Open-Coastal Wetland Sites, Central Cascadia Margin" (2000). Dissertations and Theses. Paper 3361.
https://doi.org/10.15760/etd.5246
Comments
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