Liquefaction Hazard Maps

Liquefaction, a process in which loose, granular soils below the ground water table temporarily lose strength during strong earthquake shaking, has been the cause of considerable damage during earthquakes. To provide a micro- zonation of this hazard, maps have been prepared for various subregions of the United States. These maps have been prepared under the auspices of the National Earthquake Hazards Reduction Program (NEHRP) by scientists and engineers within the U.S. Geological Survey, organizations sponsored by the USGS NEHRP External Research Pro- gram, and state government agencies. The maps aid the design professional by delineating areas where liquefaction could pose a significant hazard and should therefore be considered during facilities design. The maps can also be used by local officials and public policy makers for land-use planning and emergency response planning.

The Oregon Department of Geology and Mineral Industries (DOGAMI) has produced a series of earthquake hazard maps including liquifaction hazards.

The Washington Department of Natural Resources, Division of Gelology and Earth Resourses have produced a number of liquefaction and earthquake maps including:

OlympiaLiquifactionHazMap

Liquefaction susceptibility maps for Washington State:

Auburn and Poverty Bay

Des Moines and Renton

Greater East Side Area, King County

Olympia-Lacey-Tumwater Urban Area

Sumner

Tacoma Urban Area

Vancouver Urban Area Relative EQ Hazard Map

Washington Counties (Liquifaction and Site Class)

(The above contains maps for each Washington State County)

Washington State (Seismic Design Cat. Map)

Potential for differential settlement, Gig Harbor peninsula (1976)

The Oregon Department of Geology and Mineral Industries, DOGAMI, has published a series of relative earthquake hazard maps that include liquefaction susceptability for many Oregon counties and communities.