DOGAMI Open-File Report Series

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Open-File Report O-13-19, Tsunami inundation scenarios for Oregon, by George R. Priest, Robert C. Witter, Y. Joseph Zhang, Kelin Wang, Chris Goldfinger, Laura L. Stimely, John T. English, Sean G. Pickner, Kaleena L.B. Hughes, Taylore E. Wille, and Rachel L. Smith

Order publication CD-ROM, $30, from Nature of the Northwest.

Abstract
This digital data release is for seven tsunami inundation scenarios for the entire Oregon coast in the form of polygons (Esri ArcGIS® shapefiles). These scenarios are depicted on published Oregon Department of Geology and Mineral Industries (DOGAMI) tsunami inundation maps (TIM series). The hydrodynamic computer model SELFE is used to simulate tsunami generation, propagation and maximum inundation for five Cascadia subduction zone (CSZ) earthquake sources (SM1, M1, L1, XL1, XXL1) and two Mw (moment magnitude) 9.2 Alaska earthquake sources: the historical maximum that struck in 1964 (AK64) and a hypothetical maximum (AKMax) with highly efficient focusing of tsunami energy at the Oregon coast. Inundation for XXL1 and the AKMax are the recommended evacuation zones for local and distant tsunamis, respectively. Model CSZ slip is estimated primarily from size and time between deposits left behind by submarine sand and silt slurries (turbidites) triggered by CSZ earthquakes. Relative CSZ tsunami heights at each latitude scale directly to local peak fault slip calculated from model time intervals over which the CSZ accumulates slip that is released in earthquakes as follows: Sm1 = 300 yrs, M1 = 425-525 yrs, L1 = 650–800 yrs, XL1 = 1,050–1,200 yrs, XXL1 = 1,200 yrs. All five CSZ sources partition fault slip from the CSZ megathrust to an offshore splay fault with an average eastward inclination of ~30°. Based on a logic tree summarizing sources of variability, the five CSZ inundations cover the following percentages of potential variability in CSZ tsunami inundation: Sm1 = 26%, M1 = 79%, L1 = 95%, XL1 = 98%, and XXL1 = 100%. Model tide for all seven scenarios is assumed to be mean higher high water (MHHW), varying south to north from 2.07 m to 2.71 m NAVD88 (North American Vertical Datum of 1988). Tsunami simulations use unstructured computational grids constructed from detailed bathymetric and topographic data, particularly lidar. Spacing between computational grid points, a measure of the precision of the inundation boundaries, is generally less than 10 m in populated areas and at critical shoreline features such as jetties.

CD-ROM includes:

EvacuationBrochure_Data subfolder:
- Assembly_Areas
- CriticalFacilities
- EvacuationZones
- OutsideHazardArea_GreenHighGround

Reference_Files subfolder:
- Evacuation_Brochure_Index_Polygons
- TIM_Index_Polygons
- Tsunami_Data_GridSeams
This folder also contains the PDF file Tsunami_ProjectAreas_and_Grids_IndexMap.pdf [see below], a duplicate of Figure 3 in the text report.

Statewide_Tsunami_Scenarios subfolder:
- Statewide_AK64_Tsunami_Inundation_Scenario
- Statewide_AKMAX_Tsunami_Inundation_Scenario
- Statewide_L_Tsunami_Inundation_Scenario
- Statewide_M_Tsunami_Inundation_Scenario
- Statewide_SM_Tsunami_Inundation_Scenario
- Statewide_XL_Tsunami_Inundation_Scenario
- Statewide_XXL_Tsunami_Inundation_Scenario

Example mapviews of tsunami shapefile data for (left) five Cascadia Subduction Zone and (right) two distant tsunami scenarios in the Ophir - Nesika Beach - Gold Beach area. These seamless inundation lines cross Tsunami Inundation Map (TIM) series publication boundaries (grey outlines). The seamless data cover the entire Oregon coast.

example CSZ inundation      example distant inundation

 

Project area coverage (Figure 3 in text report).