Tsunami Design Zone Maps for Washington State Building Code

Washington State's adoption of the 2018 International Building Code (IBC) included amendments to the original code language to direct designers, engineers, and architects to use the Washington Tsunami Design Zone Maps (WA-TDZ), where available, to determine whether structures in Risk Category III or IV need to be designed for tsunamis. ASCE Tsunami Design Zones (https://asce7tsunami.online/) are to be used where WA-TDZ maps are not available. Special design parameters must be considered for structures if they are located in the WA-TDZ. Further, the code requires the use of WA DNR Tsunami Inundation Data for design purposes, or that such data be considered as a baseline for self-conducted studies. Please use the contact information at the bottom of this page to request the data or for a meeting with WGS representatives.

2018 Tsunami Design Zone Maps


Maps currently adopted for this purpose are:

  Tsunami hazard maps used for the 2018 tsunami design zone maps
Location Publication Link
Anacortes and Bellingham area MS 2018-02* Download
Elliott Bay Seattle OFR 2003-14 Download
Everett area OFR 2014-03 Download
Port Angeles and Port Townsend area MS 2018-03 Download
San Juan Islands MS 2016-01* Download
Southern Washington coast MS 2018-01 Download
Tacoma area OFR 2009-9 Download

*Designers wishing to use the latest maps can find them here.


The above list will be updated for future building codes. Future building codes will include the latest publications or updates on a schedule corresponding with the updates and adoption of the Washington State Building Code.

Please note that inundation depth values quoted in both the source publications and the raw data available from WA DNR are set to a mean high water (MHW) tidal datum. As this is higher than the standard North American Vertical Datum of 1988 (NAVD 88) used in the IBC, the values listed in the WA DNR data will need to be recalculated according to the differences between NAVD 88 and MHW at the project site. This recalculation to NAVD88 has already been conducted for the data displayed in the map below. The published maps, model data, and results within the map shown here already incorporate ground deformation (subsidence) from the earthquake in the inundation depth/elevation results. The published maps, model data, and results shown here do not include any contribution from sea level rise. Local sea level rise projections for Washington State are available here: Miller and others, 2018.

The finalized inundation elevation is the combination of land level subsidence, MHW conversion, and inundation depth.

We recommend users click the search tool in the webmap below (click the picture below to access the map in fullscreen) to jump to their project site or zoom in to an area of interest. While viewable at all scales, the identify pop-up is best used when zoomed in, or else you may accidentally select numerous adjacent data.

Click here or on the map image below to access the interactive map


Use limitations

The Washington Geological Survey (WGS) shall not be held liable for improper or incorrect use of the data described and (or) contained herein. This product is provided 'as is' without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular use. The Washington State Department of Natural Resources and the authors of this product will not be liable to the user of this product for any activity involving the product with respect to the following: (a) lost profits, lost savings, or any other consequential damages; (b) the fitness of the product for a particular purpose; or (c) use of the product or results obtained from use of the product. Although these data have been processed successfully on computers of WGS, no warranty, expressed or implied, is made by WGS regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such warranty.

Contact Us

For more information about this page and the tsunami inundation data please contact:

Corina Allen
Chief Hazards Geologist