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603284-001 <br />3.2.2 Seismically-Induced Settlement <br />Seismically-induced settlement consists of dry dynamic settlement (above <br />groundwater) and liquefaction-induced settlement (below groundwater). <br />These settlements occur primarily within loose to medium dense sandy <br />soil due to reduction in volume during, and shortly after, an earthquake <br />event. Our analysis is presented in Appendix E. <br />The seismically-induced settlement resulting from the design event is <br />estimated to be in the order of 1 to 2 inches. Differential settlement is <br />estimated to be approximately 7 inch over 100 feet. <br />3.2.3 Surface Manifestation of Liquefaction <br />Surface manifestation of liquefaction would include the formation of <br />sand/gravel boils and ground cracking. As discussed above, the site is <br />generally classified as having low risk of liquefaction based on LPI. <br />Accordingly, the potential for surface manifestations, such as sand boils or <br />bearing capacity failure of shallow foundations, is considered low. <br />3.2.4 Lateral Spreading or Flow Failure <br />For lateral spreading or flow failure to occur, a continuous, laterally <br />unconstrained liquefiable zone must be free to move along gently sloping <br />ground toward an unconfined area. The site is relatively flat. <br />Although the Santa Ana river channel and levee are located approximately <br />200 feet south and east of the site, the river channel depth is generally <br />shallower than the soil layers at the site deemed susceptible to <br />liquefaction. Accordingly, the potential for lateral spreading is deemed <br />low. <br />3.2.5 Seismically-Induced Landslides <br />According to the State of California Seismic Hazards Zones Map for the <br />Anaheim Quadrangle, the site is not located in an area potentially <br />susceptible to earthquake induced landslides. Based our experience and <br />the gently sloping topographic character of the site, the potential for <br />seismically-induced slope instability is considered low. <br />-14- <br />Leighton