Mason County

Date: July 10, 2017Sources: Mason County GIS;WADNR

Seismic Soils & Liquefaction Risk

B B-C C C-DRock Very Dense

Soil & Soft RockStiff Soil Soft

SoilRequires

Site-SpecificInvestigation

Increasing Amplification of Ground Shaking

FED-ED

Soil ClassificationSoil classification data provided by the Washington State Department of Natural Resources - Division of Geology & Earth Resources. This data has been published at a scale of 1:100,000.

The dataset identifies site classes for approximately 33,000 polygons derived from the geologicmap of Washington State. The methodology chosen for developing the site class map requiredthe construction of a database of shear wave velocity measurements. This database was createdby compiling shear wave velocity data from published and unpublished sources, and throughthe collection of a large number of shear wave velocity measurements from seismic refraction surveysconducted for this project. All of these sources of data were then analyzed using the chosenmethodologies to produce the statewide site class data.

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Kitsap

Pierce

Thurston

Allyn

Belfair

Grapeview

Hoodsport

Lilliwaup

Potlatch

Shelton

Union )l

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Kitsap

Pierce

Thurston

Allyn

Belfair

Grapeview

Hoodsport

Lilliwaup

Potlatch

Shelton

Union

Liquefactrion data provided by the Washington State Department of NaturalResources - Division of Geology & Earth Resources. This data is based solelyon surficial geology and has been published at a scale of 1:100,000.

A liquefaction susceptibility map provides an estimate of the likelihood that soilwill liquefy as a result of earthquake shaking. Mason County depicts the relativesusceptibility to liquefaction from bedrock to areas of high susceptability. Areasunderlain by bedrock or peat are mapped separately as these earthen materialsare not liquefiable, although peat deposits may be subjected to permanentground deformation as a result of earthquake shaking.

National EarthquakeHazard Reduction

Program (NEHRP) SoilsLiquefactionSusceptibility

PeatBedrock

NotSusceptible

HighModerate to HighModerateLow to ModerateLowVery Low to LowVery Low

Susceptible

Liquefaction Susceptibility