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Geologic Hazards on the Oregon Coast
A look at the new draft Cannon Beach tsunami hazard map

March 5, 2008 (draft map revised 4-18-08)

The Department of Geology and Mineral Industries (DOGAMI) has been working with coastal communities on tsunami awareness and preparedness for over a decade, making Oregon a national leader in tsunami education and mitigation.

For example, working with Oregon Emergency Management (OEM) and local governments, 27 evacuation maps and brochures have been completed for coastal communities, with over 200,000 brochures printed in 2007.

But the 2004 Indian Ocean magnitude 9.3 Sumatra-Andaman Islands earthquake and subsequent tsunami led to a re-evaluation of our tsunami hazard mapping program. Because of critical observations made about the Indian Ocean tsunami that killed over 250,000 people, DOGAMI decided a new approach in tsunami hazard assessments was needed. With the encouragement and support of NOAA, George Priest and Rob Witter of DOGAMI are now leading a technical team of researchers and scientists in this project using the latest advances in mapping technology (lidar), computer technology and computer modeling. Mapping at Cannon Beach is serving as the pilot project for this effort.

   PDF of Draft Tsunami Hazard Map of the Cannon Beach Area, Clatsop County, Oregon by George Priest and Rob Witter, DOGAMI (draft map revised 4-18-08)

This new scenario-based inundation research mapping expresses the variability of what could be expected from a tsunami impact on the Oregon coast in the event of a Cascadia subduction zone earthquake or a distant tsunami-generating earthquake, including a most likely case Cascadia event tsunami, a worst case Cascadia event tsunami, and a worst case distance tsunami.

This new map is based on exhaustive, state of the art, computer modeling and on the ground paleo-tsunami mapping field work aimed at identifying the extent of prehistoric tsunami deposits and DOGAMI is working closely with Cannon Beach officials in the release of this map. The draft map on this page [and mentioned in an Oregonian article of March 9th, 2008] is still being finalized and has not been through technical review. The finished map will be released later in 2008.

It is hoped this new generation of tsunami inundation maps will be easily interpreted by the general public in order for them to be more useful. DOGAMI will use this new research and mapping techniques to collaborate with coastal communities in also creating a new generation of tsunami evacuation brochures and maps. How these new maps are translated into public policy, land use planning, and are used for evacuation planning will need to be unique to each community.

For more on tsunamis in Oregon, click on the links below:

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Oregon Department of Geology and Mineral Industries
800 NE Oregon Street, Suite 965, Portland, OR 97232-2162
971-673-1555, FAX 971-673-1562
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