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Geology

Dissertations and Theses

Theses/Dissertations

Subsidences (Earth movements) -- Washington (State)

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Full-Text Articles in Physical Sciences and Mathematics

Potential For Coastal Flooding Due To Coseismic Subsidence In The Central Cascadia Margin, Elson T. Barnett Jan 1997

Potential For Coastal Flooding Due To Coseismic Subsidence In The Central Cascadia Margin, Elson T. Barnett

Dissertations and Theses

Interpretations made from compilation of existing core and cutbank data for Oregon and Washington are used to evaluate the potential flooding impact from regional coseismic subsidence. Estimates of regional subsidence are based on tidal level indicators including plant macrofossils, peat development, and diatoms. A compilation of existing late Holocene stratigraphic records shows multiple burial events in all bays of Oregon, however some coastal sites in central Oregon show continuous submergence. Tests of tidal level indicators using modern Cascadia wetlands indicate that paleosubsidence can be estimated to 0.0 ± 0.5m, 1.0 ±0.5m, and 2 m ± 0.5m. An AMS date from …


Beach Response To Subsidence Following A Cascadia Subduction Zone Earthquake Along The Washington-Oregon Coast, Debra Lee Doyle Jun 1996

Beach Response To Subsidence Following A Cascadia Subduction Zone Earthquake Along The Washington-Oregon Coast, Debra Lee Doyle

Dissertations and Theses

Beach shoreline retreat induced by coseismic subsidence in the Cascadia subduction zone is an important post-earthquake hazard. Sand on a beach acts as a buffer to wave attack, protecting dunes, bluffs and terraces. The loss of sand from a beach could promote critical erosion of the shoreline. This study was initiated in order to estimate the potential amount of post subsidence shoreline retreat on a regional scale in the Central Cascadia Margin. The study area is a 331 km stretch of coastline from Copalis, Washington to Florence, Oregon. Several erosion models were evaluated, and the Bruun model was selected as …