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Open-File Report O-19-05, Tsunami evacuation analysis of Newport, Lincoln County, Oregon,
by Laura L. S. Gabel, Fletcher E. O'Brien, and Jonathan C. Allan; 61 p. report, one Esri® geodatabase with internal metadata, external metadata in .xml format.

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ABSTRACT
We evaluated pedestrian evacuation in the city of Newport and surrounding areas, including Agate Beach, Nye Beach, the Bayfront, South Beach, and Ona Beach, Lincoln County, in the event of a local tsunami generated by an earthquake on the Cascadia subduction zone (CSZ). Our analyses focused on a maximum-considered CSZ tsunami event covering 100% of potential variability, termed XXL1 and generated by a magnitude 9.1 earthquake. Evacuation paths were limited to roads, trails, and pedestrian pathways designated by local government reviewers as the most likely routes.

To assist in understanding pedestrian tsunami evacuation, we produced maps and digital data that include the following:

• Tsunami wave advance for an XXL1 event,
• Detailed “Beat the Wave” (BTW) results for the XXL1 scenario, including evacuation routes, minimum walking speeds, and evacuation flow zones,
• Detailed BTW results for the L1 scenario for select locations, and
• BTW results for multiple hypothetical scenarios.

The BTW maps depict the minimum evacuation speed required to stay ahead of the tsunami wave given a variety of scenarios that will increase evacuation difficulty. The primary scenario uses the existing road network and includes a 10-minute delay from start of earthquake before beginning evacuation. Additional challenges to evacuation are discussed, including failure of non-retrofitted bridges and effects from landslides and liquefaction. In all cases, the identified minimum speeds must be maintained for the entire time it takes to evacuate from the inundation zone.

Given the model limitations defined in the Methods section, results show that evacuation of north Newport is achievable at a moderate walking speed (4 fps). Even for those with mobility limitations (i.e., those who cannot travel at speeds more than 4 fps), safety can be reached ahead of the wave from nearly every location. Results for south Newport vary widely. The vertical evacuation structure currently under construction at the Oregon State University (OSU) Hatfield Marine Science Center will greatly improve survivability from a local tsunami, enabling staff, students, and the public to more easily reach high ground. For example, evacuation at a moderate walking speed (4 fps) is achieved for the entire Hatfield peninsula given the presence of this structure. It is the first of its kind to be built on the Oregon coast and only the second in the United States. The highest minimum walking speeds are found in South Beach State Park (6 fps without liquefaction). Liquefaction is not expected to present a significant challenge to evacuation in north Newport. However, in south Newport liquefaction could present a significant challenge to evacuation across the region.

Possible mitigation options include adding new evacuation routes; constructing more earthquake-hardened roads (built or remodeled to withstand shaking from a major earthquake and liquefaction); and/or installing a tsunami refuge, otherwise known as a vertical evacuation structure, at South Beach State Park.


GEOGRAPHIC INFORMATION SYSTEM (GIS) DATA

Geodatabase is Esri® version 10.1 format.
Metadata is embedded in the geodatabase and is also provided as separate .xml formatted files.

Pacific_City_Tsunami_Evacuation_Modeling.gdb (GIS data bundle zip file)
   rasters
         MaxTsunamiFlowDepth_XXL1 The maximum tsunami flow depth raster shows the maximum tsunami flow depths estimated for a maximum-considered XXL1 tsunami caused by a magnitude 9.1 CSZ earthquake. Data are from DOGAMI Open-File Report O-13-17. Flow depths were not directly incorporated into the evacuation difficulty analysis but are included in this report to assist in the evaluation of mitigation options. .xml
         TsunamiWaveArrival_XXL1 The tsunami wave arrival time raster shows estimated wave arrival times for a maximum-considered XXL1 tsunami caused by a magnitude 9.1 CSZ earthquake. The tsunami starts toward shore at the moment the earthquake starts, but the shaking from the earthquake can last three to five minutes. Wave arrivals are shown as the time when wave depth reaches 6 inches or greater at any location, and arrivals are timed from the start of the earthquake. .xml
 
  feature dataset - L1_BridgesOut
We calculated BTW results for the Large tsunami scenario, termed L1, which covers 95% of potential variability and is generated by a magnitude 9.0 earthquake. This provides alternative safety destinations for areas where evacuation from XXL is unlikely.
         L1_BridgesOut_EvacuationFlowZones Polygons. Evacuation flow zones depict the nearest safety destination for every point in the inundation zone (on the road and trail network) assuming all non-retrofitted bridges within the inundation zone fail due to earthquake shaking. .xml
         L1_BridgesOut_EvacuationRoutes Polylines. Evacuation routes depict the most efficient routes to safety for every point in the inundation zone (on the road and trail network) assuming all non-retrofitted bridges within the inundation zone fail due to earthquake shaking. .xml
         L1_BridgesOut_WalkingSpeeds_Roads Polygons. Minimum evacuation speeds needed to stay ahead of the wave assuming all non-retrofitted bridges within the inundation zone fail due to earthquake shaking. This feature class contains BTW data on paved roads. .xml
         L1_BridgesOut_WalkingSpeeds_Trails Polylines. Minimum evacuation speeds needed to stay ahead of the wave assuming all non-retrofitted bridges within the inundation zone fail due to earthquake shaking. This feature class contains BTW data on trails and beach networks only. .xml
 
   feature dataset - XXL1_BridgesOut
Analyses focused on a maximum-considered Cascadia Subduction Zone tsunami event covering 100% of potential variability, termed XXL1 and generated by a magnitude 9.1 earthquake. Assume all non-retrofitted bridges within the inundation zone fail due to earthquake shaking.
         XXL1_EvacuationFlowZones Polygons. Evacuation flow zones depict the nearest safety destination for every point in the inundation zone (on the road and trail network) assuming all non-retrofitted bridges within the inundation zone fail due to earthquake shaking. .xml
         XXL1_EvacuationRoutes Polylines. Evacuation routes depict the most efficient routes to safety for every point in the inundation zone (on the road and trail network) assuming all non-retrofitted bridges within the inundation zone fail due to earthquake shaking. .xml
         XXL1_WalkingSpeeds_Roads Polygons. Minimum evacuation speeds needed to stay ahead of the wave assuming all non-retrofitted bridges within the inundation zone fail due to earthquake shaking. This feature class contains BTW data on paved roads only. .xml
         XXL1_WalkingSpeeds_Trails Polylines. Minimum evacuation speeds needed to stay ahead of the wave assuming all non-retrofitted bridges within the inundation zone fail due to earthquake shaking. This feature class contains BTW data on trails and beach networks only. .xml