New modeling data published by the state gives a glimpse of a bigger earthquake than Willapa Bay and Grays Harbor have ever seen. Called a 2,500-year event, the modeled quake in the Cascadia Subduction Zone would drop one side of our fault line 88.6 feet, and send the first tsunami wave to the outer coast in 15 to 20 minutes.
Wave heights would depend on bathymetry and topography, but the amount of inundation worries the Department of Natural Resources. Inundation is the total water level that occurs on normally dry ground. – that could range from 20 to 60 feet on the outer coast, and closer to 10 feet in Willapa Bay and Grays Harbor. The North Jetty and Damon Point in Ocean Shores could see over 60 feet of water. Ocean City and the Screamin’ Eagle Campground nearby could see nearly 50 feet of inundation.
Tsunami waves will travel at about 40 mile per hour, or 35 knots to the maritime community. Tsunami wave inundation is expected to continue over 12 hours and remain hazardous to maritime operations for more than 24 hours after the earthquake.
While this model tries to grasp an event bigger than the 1700 flood that created the ghost forest in Copalis, Your response should be the same for any earthquake felt along the coast wait until the shaking has finished and it’s safe, then move to higher ground.