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<br /> <br /> 4 Parsons-1-01 <br /> <br /> <br />2 0 2 2 C B C S e i s m i c P a r a m e t e r s <br />2022 CBC Seismic Design Parameters Value <br />Site Latitude (decimal degrees) 33.7560 <br />Site Longitude (decimal degrees) -117.9316 <br />Site Class Definition D <br />Mapped Spectral Response Acceleration at 0.2s Period, Ss 1.338 <br />Mapped Spectral Response Acceleration at 1s Period, S1 0.476 <br />Short Period Site Coefficient at 0.2s Period, Fa 1.2 <br />Long Period Site Coefficient at 1s Period, Fv 1.824 <br />Adjusted Spectral Response Acceleration at 0.2s Period, SMS 1.606 <br />Adjusted Spectral Response Acceleration at 1s Period, SM1 0.868 <br />Design Spectral Response Acceleration at 0.2s Period, SDS 1.07 <br />Design Spectral Response Acceleration at 1s Period, SD1 0.579 <br /> <br />6.0 LIQUEFACTION POTENTIAL <br />For liquefaction to occur, all of three key ingredients are required: liquefaction-susceptible <br />soils, groundwater within a depth of 50 feet or less, and strong earthquake shaking. Soils <br />susceptible to liquefaction are generally saturated loose to medium dense sands and non-plastic <br />silt deposits below the water table. <br />According to the “Map of Seismic Hazard Zones”, prepared by the California Geologic Survey, <br />the site is located within a liquefaction hazard zone. The site is currently developed with <br />existing residential building supported on shallow foundation system. Liquefaction mitigation <br />measures are not warranted. It is our opinion that potential for liquefaction at the site is low to <br />moderate and will not adversely impact the proposed construction. We recommend that the <br />proposed Accessory Dwelling Unit be supported on shallow foundation system. <br />7.0 DESIGN RECOMMENDATIONS <br />Based upon the results of our investigation, the proposed ADU is considered geotechnically <br />feasible provided the recommendations presented herein are incorporated into the design and <br />construction. If changes in the design of the structure are made or variations or changed <br />conditions are encountered during construction, GeoBoden should be contacted to evaluate <br />their effects on these recommendations. The following geotechnical engineering