Open File Report 2004-20
Liquefaction Susceptibility and Site Class Maps of Washington State, by County
by Stephen P. Palmer, Sammantha L. Magsino, Eric L. Bilderback, James L. Poelstra, Derek S. Folger, and Rebecca A. Niggemann
Available online only
In response to the Nisqually earthquake of 2001, DGER was awarded a grant by the Federal Emergency Management Agency and Washington Emergency Management Division to develop two types of earthquake hazard maps for every county in the state—liquefaction susceptibility maps, which outline areas where water-saturated sandy soil loses strength during earthquake shaking, and NEHRP (National Earthquake Hazards Reduction Program) site class maps, which outline areas where soils amplify ground shaking. The maps will be used by state and local governments to update existing hazard mitigation plans and to delineate geologically hazardous areas under the Growth Management Act.
The project team completed and released a preliminary version of these statewide hazard maps in September 2003. The project team has now completed the final liquefaction susceptibility and NEHRP site class maps that include the results of more than 90 shear-wave velocity surveys and evaluation of geotechnical boring and water well data.
This publication supersedes a previous release of these maps and data in September 2004.
HOW TO DOWNLOAD
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Maps and Accompanying Report
Clicking on the download links above will take you to a Department of Natural Resources’ FTP site—please read the information below on proper use of this FTP site.
USING THE FTP SITE
This service may be monitored to ensure proper operation; to verify applicable security features are functioning; its use is consistent with State and DNR policies regarding Ethics and Internet use; and for other like purposes. Individuals using this FTP server expressly consent to such monitoring.
DNR and its officials and employees assume no responsibility or legal liability for the accuracy, completeness, reliability, timeliness, or usefulness of any of the information provided. The information is collected from various sources and will change over time without notice.
Downloading the Geospatial Data
To download the data, open the folder of the data that you are interested in and from there, copy the folder of the county you are interested in to your computer by right-clicking on the folder, and then click Copy to Folder.
The GIS files are in ESRI shapefile format, and require either a commercial GIS program or a free GIS data viewer such as ArcGIS Explorer for use.
The Department of Natural Resources is not able to support your GIS software—please contact the software manufacturer for software support.