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MainPlace Mall Transformation Project 12126.001 <br />located approximately 4 miles north of the project site. Based on these <br />conditions, methane hazard is not a consideration for the project. <br />Design Consideration: Emission of methane gas is not a design <br />consideration for the project. <br />3.14 Regional Subsidence <br />Regional ground subsidence generally occurs due to rapid and intensive removal <br />of subterranean fluids, typically water or oil. It is generally attributed to the <br />consolidation of sediments as the fluid in the sediment is removed. The total <br />load of the soils in partially or fully saturated deposits is born by their granular <br />structure and the fluid. When the fluid is removed, the load is born by the <br />sediment alone and it settles. No reports on regional subsidence due to fluid <br />removal have documented subsidence in the site vicinity, and the project would <br />not involve the removal of water or oil at the site, making the potential for ground <br />subsidence related to fluid removal is not a geologic hazard. <br />Design Consideration: According to the City of Santa Ana's General Plan, <br />Seismic Safety Element (City of Santa Ana, 1982), portions of the project site <br />are located within an area delineated as having a potential for regional <br />subsidence due to seismically -induced settlement of loose and sandy soil. <br />However, as previously addressed in Section 3.4, the potential effects relating <br />to seismically -induced settlement can be reduced by following implementation <br />of engineering practices in remedial earthwork, structural design for new <br />buildings and/or ground improvement techniques. <br />3.16 Summary of Geologic and Seismic Hazards Review <br />The results of our geologic and seismic hazards review are summarized below. <br />13 <br />!oto <br />jo <br />Leighton <br />