New Maps Show Cascadia Tsunami Impacts for Anacortes, Bellingham
News Date: 
July 2, 2018

Study shows waves that will arrive 1.5 hours after Cascadia quake

The Washington State Department of Natural Resources (DNR) published today new maps showing the likely impacts to communities on the north Salish Sea mainland from a tsunami generated by a magnitude 9 earthquake on the Cascadia subduction zone.
These new maps are prepared by the Washington Geological Survey, a division of DNR, and are intended to help local officials prepare evacuation and recovery plans.
“Earthquakes and tsunamis are very real threats that we must be proactive in preparing for,” said Commissioner of Public Lands Hilary Franz. “That’s why DNR’s team of highly-trained geologists works each day to ensure our communities have the information they need to prepare and be safe.”
The new modeling uses a simulated magnitude 9 earthquake on the Cascadia subduction zone – an event that geologic history shows occurring approximately every 2,500 years. This modeling follows building code standards for critical facilities, and assumes greater inundation than previous modeling so communities can plan for worst outcomes.
This modeling indicates the first tsunami waves will reach the Anacortes/Bellingham areas about 1.5 hours after the Cascadia earthquake, with inundation depths as high as 18 feet and current velocities in excess of 20 knots. Tsunami inundation is expected to continue for more than 8 hours.
The information will be added DNR’s Geologic Information Portal later this year.
Geology in the Public Interest
Under the guidance of Commissioner of Public Lands Hilary Franz, the Washington Geological Survey works to ensure the safety and economic well-being of Washington’s citizens from geologic events. The Survey is the primary source of geological products and services for Washington’s government agencies, businesses, and the public.

Joe Smillie
Communications Manager