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Open-File Report 2006-1234
Version 1.0

Seaside, Oregon Tsunami Pilot Study—Modernization of FEMA Flood Hazard Maps

By Tsunami Pilot Study Working Group


Perspective view of 500-year tsunami in the Seaside/Gearhart, Oregon, pilot study area. Tsunami wave heights (m) with a 0.2% annual probability of exceedance. Wave heights include the effects of tides. Vertical exaggeration 10x; view looks southeastward.


FEMA Flood Insurance Rate Map (FIRM) guidelines do not currently exist for conducting and incorporating tsunami hazard assessments that reflect the substantial advances in tsunami research achieved in the last two decades; this conclusion is the result of two FEMA-sponsored workshops and the associated Tsunami Focused Study. Therefore, as part of FEMA’s Map Modernization Program, a Tsunami Pilot Study was carried out in the Seaside/Gearhart, Oregon, area to develop an improved Probabilistic Tsunami Hazard Assessment (PTHA) methodology and to provide recommendations for improved tsunami hazard assessment guidelines. The Seaside area was chosen because it is typical of many coastal communities in the section of the Pacific Coast from Cape Mendocino to the Strait of Juan de Fuca, and because State Agencies and local stakeholders expressed considerable interest in mapping the tsunami threat to this area. The study was an interagency effort by FEMA, U.S. Geological Survey and the National Oceanic and Atmospheric Administration, in collaboration with the University of Southern California, Middle East Technical University. Portland State University, Horning Geosciences, Northwest Hydraulics Consultants, and the Oregon Department of Geological and Mineral Industries. Draft copies and a briefing on the contents, results and recommendations of this document were provided to FEMA officials before final publication.

Tsunami Pilot Study Working Group

Frank González NOAA/PMEL
Eric Geist U.S. Geological Survey
Costas Synolakis Univ. of Southern California
Diego Arcas NOAA/PMEL
Doug Bellomo FEMA, Dept. of Homeland Security
David Carlton FEMA, Dept. of Homeland Security
Tom Horning Horning Geoscience
Bruce Jaffe U.S. Geological Survey
Jeff Johnson Northwest Hydraulics Consultants
Utku Kanoglu Middle East Technical University, Ankara, Turkey
Hal Mofjeld NOAA/PMEL
Jean Newman NOAA/PMEL
Tom Parsons U.S. Geological Survey
Robert Peters U.S. Geological Survey
Curt Peterson Portland State University
George Priest Oregon Dept. of Geology & Minerals
Vasily Titov NOAA/PMEL
Angie Venturato NOAA/PMEL
Joe Weber FEMA, Dept. of Homeland Security
Florence Wong U.S. Geological Survey
Ahmet Yalciner Middle East Technical University, Ankara, Turkey


Download Open-File Report 2006-1234 as a 161-page PDF file (61.6 MB)

Download Plate 1 as a 58"x28" PDF file (2.8 MB)

see also: USGS Data Series 236: Seaside, Oregon, Tsunami Pilot Study - Modernization of FEMA Flood Hazard Maps: GIS Data []

For questions about the content of this report, contact Eric Geist

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Maintained by: Michael Diggles
Created: September 1, 2006
Last modified: January 18, 2007 (mfd)