USA, Washington: New maps help you walk away from tsunami

Knowing where to walk and how long it might take to get there can be one of the most important pieces of information for anyone in Washington’s coastal communities when a tsunami strikes.

People that live work and play near the coast in Washington State are at risk for tsunamis. Our main causes of tsunamis in Washington are from earthquakes and landslides. If you feel an earthquake, that’s your warning and you should evacuate and get to high ground immediately.

That’s why the geologists at the Washington State Department of Natural Resources (DNR) have just published evacuation walk time maps for Port Angeles, Bellingham, Anacortes, Aberdeen, Hoquiam and Cosmopolis.

These maps, produced by the Washington Geological Survey within DNR, show the time it would take to evacuate on foot from the tsunami inundations zones of a Cascadia subduction zone earthquake. The walking pace is modeled at a slow walk pace, using the timing of crosswalks, adjusted for different terrain.

Using models of a Cascadia earthquake, the maps use colors to indicate how many minutes it would take to walk to safety at a moderate pace within these communities. Waves from a Cascadia earthquake-induced tsunami could reach Aberdeen in as soon as 15 to 20 minutes.

319 years since Cascadia last quaked

The geologic record shows the Cascadia subduction zone – the offshore area where the Juan de Fuca tectonic plate pushes under the larger North American plate – produces megathrust quakes every 300 to 600 years.

These maps are modeled on a magnitude 9 Cascadia earthquake. The geologic record shows earthquakes of this size occur approximately every 2,500 years, with the last striking in 1700.

Models, maps available online

The new pedestrian maps and maps for other communities are available through the interactive map on our web site.

The interactive map also provides access to tsunami evacuation brochures for areas that do not have walk time maps yet.

Other information about impacts from earthquakes to Washington communities is available on our Geologic Information Portal.

Geologists to discuss tsunami hazards at coastal Road Show next week

Washington Geological Survey geologists will present evacuation information and more with tsunami and earthquake experts from the Washington Emergency Management Division, the National Weather Service, Washington Sea Grant and local officials at next week’s Tsunami Road Show.