New videos show tsunami impacts in Washington

New videos allow Washington residents to see simulated models of how large tsunami waves are likely to impact their communities.

Scientists with the Washington State Department of Natural Resources have just released a series of modeled simulation videos that show tsunamis started by a magnitude 9.0 earthquake on the Cascadia subduction zone.

Using detailed tsunami models, the simulations show the estimated height and speed of waves that are expected to reach Washington communities minutes after the next Cascadia earthquake.

“We know tsunamis will hit our state. It’s a question of when, not if, which means we need to prepare now. Our hope is that these stark videos drive home the need for communities to take action to become more secure and resilient,” said Commissioner of Public Lands Hilary Franz.

The videos show Cascadia tsunami wave simulations for the entire Washington coast and Columbia River estuary, as well as more detailed, localized views for Bellingham and the San Juan Islands.

The simulations show the first waves reaching the outer coast in about 15 minutes. The tsunami then travels through the Strait of Juan de Fuca and into Puget Sound, reaching the Tacoma waterfront about two hours and 30 minutes after the earthquake. These simulations also show how tsunami waves will continue to affect Washington communities for several hours after the earthquake.

They are available on DNR’s YouTube channel at: https://bit.ly/2UakcB8.

The last magnitude 9 Cascadia subduction zone earthquake struck in 1700 and produced a tsunami that left sand deposits and drowned forests, which can still be seen in places like the Copalis Ghost Forest in Grays Harbor County. 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. There have been about 40 earthquakes on the subduction zone in the last 10,000 years.

The video simulations add to the suite of tsunami preparation materials developed by the geologists within DNR’s Washington Geological Survey.

More detailed maps of tsunami hazards, along with evacuation maps, preparation tips and additional information about these simulations are available online at https://www.dnr.wa.gov/tsunami.