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1 II ~ 1 ~ Environmental Checklist For CEQA Compliance A-3 Less Than Significant with Mitigation Incorporated. The site is within an area identified as having a potential for soil liquefaction when subject to a seismic event (Associated Soils Engineering 2006). The term liquefaction describes a phenomenon in which a saturated, cohesion less soil loses strength and acquires a degree of mobility as a result of strong ground shaking during an earthquake (Associated Soils Engineering 2006). The factors known to influence liquefaction potential include soil type and depth, grain size, relative density, groundwater level, degree of saturation, and both the intensity and duration of ground shaking (Associated Soils Engineering 2006). Catastrophic failure of structures due to soil liquefaction is not expected at the site, but the ground shaking associated with a large magnitude earthquake would likely cause settlement and/or small scale lateral displacements in local areas (Associated Soils Engineering 2006). All demolition would occur in accordance with building and safety standards as specified by the City Building Division. All site preparation (including grading) and construction of the residential units would occur in accordance with building and safety standards as specified by the City Building Division, which inherently provide for measures to reduce the potential impacts of liquefaction to structures. In addition, the geotechnical study provides for certain design measures during site preparation, excavation, grading, and construction, which would also reduce any potential impacts related to liquefaction (Associated Soils Engineering 2006). These design measures include, but are not limited to: • Specific site preparation and grading techniques to reduce liquefaction impacts such as over excavation. • Additional testing for the degree of soil expansion on site during or after rough grading operations. • Specific foundation designs to reduce provide sound structural design on potentially expansive soils. • Conformance of foundation design and asphalt design to Greenbook requirements. Therefore, the impacts to structures can be mitigated to less than significant with the implementation of mitigation measure GEO-1. Mitigation Measures GEO-1. To mitigate the effects of liquefaction, the applicant will follow the safety and building standards specified by the City Building Division as well as implement the appropriate combination of design recommendations outlined in the Associated Soils Engineering (2006) geotechnical report (Appendix B). The engineering plans will be submitted to the City's Building Department for a plan check along with the geotechnical report and will receive appropriate approvals and clearances prior to construction occurring onsite. A-4 No Impact. The project area is generally flat, and implementation of the proposed project would not require slope cuts that could result in landslides. There is no indication that recent landslides or unstable slope conditions exist on or adjacent to the project site that would otherwise result in a landslide hazard to the proposed project (Associated Soils Engineering 2006). According to the Seismic Hazards Zone Map, the site is not located within an area identified as having a potential for earthquake-induced landslides (CGS 1998 in Associated Soils Engineering 2006). Therefore, no impacts associated with landslides would occur. Alton Court August 2007 Initial Study/Mitigated Negative Declaration 3-23 J&S 00635.07 75A-89