New to the area? You know we get tsunamis here too, right? Just not very often - thankfully.
Seattle's known for its waterfront. Water defines the city's shape, image, commerce, and neighborhoods. Usually the water moves quietly as rain or comes and goes with the tide; but sometimes, the water stands up and walks across the land as a tsunami. It's just visiting, but you don't want a wall of water knocking on your front door.
The big tsunamis we've heard about in Indonesia and Japan can occur out along Washington's coast, too. Someday the Juan de Fuca plate will slip. Ocean Shores will be in the news. The waves may reach into Puget Sound (knock, knock, Port Angeles and north Whidbey Island, but that may not even be the biggest tsunami threat for Seattle.
Seattle has its faults, literally, as in fractures in the earth. One fault runs under the city. It's almost as if the Dennys settled on it to make sure their city was dynamic. Tsunamis don't happen on their own. Quakes set them off. When the Seattle Fault lets go, Elliott Bay becomes a bathtub being sloshed around by an upset kid on a grand scale.
NOAA has simulated what may happen. Waves within the normally quiet bay may suddenly rise up 2 meters. Harbor Island may be more harbor than island. Interbay will be a bay for an interim. The waves won't stay within the basin, and will probably head upstream, washing the Duwamish and the businesses along its banks. Just like in a bathtub, a wave running up one side will splash back and head to the opposite shore. The 2 meter wave may splash a bit higher on steep shores and then run back across the bay. If there's nothing to stop it, it will run far inland across flatter land.
NOAA's local research center has a tsunami warning site that's useful for the waves that cross oceans. The best warning in Seattle will be the area-wide shaking. If you're near the water and the ground shakes, move to high ground. Those evacuation signs we usually ignore may become the most important sign to read that day.
If it happens during the day, high-tech Seattle will probably produce hundreds of YouTube uploads. The evening commute is usually a mess, but after a tsunami, mud and debris may join the traffic. Businesses and houses that are high enough may not notice anything, though they may be busy reacting to the quake that started it all. Boats from Japan's tsunami eventually ended up on Washington's shore. Bremerton may get a few Seattle boats headed its way, and vice versa.
If it happens at night, wake up! Take the quake precautions and keep in mind the tsunami responses. It's a good time to have that grab and go bag by the door.
This all sounds like Seattle's problem but a quake that big will be felt all around the Sound. And, a tsunami in Elliott Bay has nothing to stop it from running north past Edmonds and south to Tacoma. Looks like we all live in a dynamic place. Now, to find the right house that's on stable ground that's above the tidal zone that has a view and a good commute and good schools...
· Seattle Fault [wikipedia]
· Seattle Tsunami NOAA Simulation [YouTube]
· National Tsunami Warning Center [NOAA}
· Juan de Fuca plate [WA Dept. of Ecology]
· How To Prepare for Tsunamis [City of Seattle]
· WA Tsunami Prep [WA DNR]
· Is Seattle Ready To Deal With a Major Earthquake? [CS]
Written by Tom Trimbath.