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January 13,2016 <br /> Project No. T-7342 <br /> 4.3 Seismic Hazard Areas <br /> Section 37.080.A.2 of the EMC defines seismic hazard areas as: <br /> "a. Those areas mapped as seismic/liquefaction hazards per the Dames and Moore Methodology for the <br /> Inventory, Classification, and Designation of Geologically Hazardous Areas, City of Everett, <br /> Washington: July 1, 1991. <br /> b. Those areas mapped as high and moderate to high liquefaction susceptibility on the Liquefaction <br /> Susceptibility Map of Snohomish County, Washington,Washington State Department of Natural <br /> Resources,Palmer, Stephen,et al., September,2004." <br /> Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength due to an increase in <br /> water pressure induced by vibrations. Liquefaction mainly affects geologically recent deposits of fine-grained <br /> sands that are below the groundwater table. Based on the soil and groundwater conditions we observed in our <br /> site explorations, it is our opinion that there is no risk for liquefaction to occur at this site during a severe seismic <br /> event. <br /> The site is underlain by glacially consolidated and overridden sediments and it is our opinion that the potential <br /> for earthquake damage at the site resulting from seismically induced differential settlement, and ground shaking <br /> is negligible. According to the Liquefaction Susceptibility Map of Snohomish County, Washington, dated 2004 <br /> the site is located in a low to very low liquefaction susceptibility area. Therefore, according to the criteria <br /> presented in item(b)above,the site is not considered a seismic hazard area. <br /> 4.5 Seismic Design Parameters: <br /> Based on soil conditions observed in the test pits and our knowledge of the area geology, per Chapter 16 of the <br /> 2012 International Building Code (IBC), site class "C" should be used in structural design. Based on this site <br /> class, in accordance with the 2012 IBC,the following parameters should be used in computing seismic forces: <br /> Seismic Design Parameters(IBC 2012) <br /> Spectral response acceleration(Short Period), ST,,, 1.451 <br /> Spectral response acceleration (1 —Second Period), Smi 0.725 <br /> Five percent damped 2 second period,SDs 0.967 <br /> Five percent damped 1.0 second period, SDI 0.483 <br /> Values determined using the United States Geological Survey (USGS) Ground Motion Parameter Calculator <br /> accessed on January 8,2016 at the web site http://earthquake.usgs.gov/designmaps/us/application.php. <br /> Page No. 7 <br />