Tsunami hazards in Washington State
Tsunamis are large and potentially dangerous waves caused by earthquakes, landslides, volcanic eruptions, exceptional weather systems, and meteorite impacts. Tsunamis have struck Washington in the past, and are expected to do so again in the future. You can learn more about tsunami hazards on the WGS website.
The Washington Geological Survey (WGS) investigates the potential impacts of tsunamis on Washington State. From this research, WGS has developed models that simulate specific aspects of how a tsunami could affect waterways and inundate land. These include quantifying inundation (flooding caused by a tsunami), current velocities (the speed that water will flow during a tsunami), arrival times of waves, and wave duration for a range of tsunami scenarios.
Building Codes and the Washington Tsunami Design Zone (WA-TDZ)
To make critical structures such as hospitals, police stations, and vertical evacuation refuges more resilient to tsunamis, the latest update to the Washington State Building Code (the 2021 International Building Code with amendments) requires certain structures located in areas affected by tsunamis to adhere to specific engineering and construction standards. To determine if a location could be inundated by a tsunami—and therefore must adhere to these higher engineering standards—engineers use a product from the Washington Geological Survey called the Washington Tsunami Design Zone (WA-TDZ). The WA-TDZ delineates inundation areas and compiles the best available tsunami modeling from WGS and from partners for this purpose.
Accessing the WA-TDZ
The WA-TDZ is hosted on the WGS website on its own dedicated page.
The webpage features an interactive map where users can access site-specific tsunami information. The webpage also links to the original map publications cited in the building code. The interactive map and publications include tsunami inundation extent (runup), inundation elevation, and maximum current velocity. Zooming in and clicking on a location of interest in the interactive map will display these key parameters for that location.
More technical details, and links to the interactive map and TDZ publications, are all available on the WA-TDZ webpage.
WASHINGTON STATE GEOLOGY NEWS 