The Oregon Department of Geology and Mineral Industries is ready to offer local residents and visitors a clear picture of what to expect in the event of either a near shore or distant earthquake that would generate tsunami waves. The state agency has developed city specific evacuation route maps for the North Oregon Coast that shows which areas are likely to be above water if a tsunami were to impact Seaside, Gearhart, Cannon Beach, Warrenton, or Astoria. The maps are based on data collected to model what the wave heights might be and how long those sets of waves would impact those coastal communities. The experts say that a near-shore quake could send the first big waves rolling in as little as twenty minutes from the first time ground movement is felt. In the case of distant events, those first waves could be as far away as 8 hours, or more . Since a tsunami is not just one large wave but a series of wave sets it could be a long as 24 hours before the danger subsides. These are educated guesses based on available data and what scientists already know about typical tsunami events. The data is getting better and more detailed. In the latest version presented to the Clatsop County Commission on Wednesday morning the experts are now able to estimate the percentage of structures that would be impacted given different circumstances and for low lying areas they have now identified a few more spots that people can go to to get out of danger.
All the information is available on a website that includes the maps for evacuation routes and gathering spots and can be found at www.oregontsunami.org along with deatils about community information meetings planned for next week.
The next job is getting that information out to the general public and working out how to get that information to visitors who may lease a house for the summer and not be aware of the plan. For locals the education process begins right away with public meetings planned to begin this month. June 20 in Warrenton, June 22 in Astoria, June 27 in Seaside and June 29 in Arch Cape.