Tsunami hazard map for Yaquina Bay area shows risk zones

The Oregon Department of Geology and Mineral Industries (DOGAMI) has released a new map that maps the hazard of tsunami inundation in the Yaquina Bay area. The map is intended primarily for planning for evacuation in the event of a tsunami but could also be adopted as a basis for planning and decisions in the areas of building code, construction, or insurance ratings.

Entitled Tsunami Hazard Map of the Yaquina Bay Area, Lincoln County, Oregon, the map has been released in the DOGAMI Interpretive Map Series as map IMS–2 (price $6). It was produced by Dr. George R. Priest in cooperation with scientists from the Oregon Graduate Institute of Science and Technology, the Center for Tsunami Inundation Mapping Effort of the National Oceanic and Atmospheric Administration (NOAA) at Newport, Oregon, and the Department of Geology at Portland State University.

The tsunami hazard map shows a black-and-white air-photo image of the coastal zone, approximately from Northwest 15th Street in the north to Henderson Creek and the south end of King Slough in the south with elevation contours superimposed. The scale of 1:12,000 (1 inch = 1,000 feet) allows identification of streets and medium-sized structures. Three different types of red lines mark expected tsunami runup elevations that serve to separate risk zones: high runup, moderately high runup, and moderately low runup. The map also identifies drill sites where cores revealed buried soils and, in some cases, tsunami sand layers from prehistoric events.

Detailed discussion of the map and its use, the development of the methods used to produce the map, and the geologic evidence of prehistoric earthquakes and tsunamis on the coast is provided in a separate publication, entitled Cascadia Subduction Zone Tsunamis: Hazard Mapping at Yaquina Bay, Oregon. Final Technical Report to the National Earthquake Hazard Reduction Program, and released in December 1997 as DOGAMI Open-File Report O–97–34 (price $10).

The new publications are now available over the counter, by mail, FAX, or phone from the Nature of the Northwest Information Center, Suite 177, State Office Building, 800 NE Oregon Street #5, Portland, Oregon 97232-2162, phone (503) 872-2750, FAX (503) 731-4066; and the DOGAMI field offices: 1831 First Street, Baker City, OR 97814, phone (541) 523-3133, FAX (541) 523-5992; and 5375 Monument Drive, Grants Pass, OR 97526, phone (541) 476-2496, FAX (541) 474-3158. Orders may be charged to Visa or Mastercard. Orders under $50 require prepayment.