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7.B. - Page 99 Redwood City Chapter 4.Environmental Impact Analysis Standard Condition 4.8-1 (2007 FEIR Standard Condition 4.8-1): The project shall comply with seismic design criteria in the California Building Code,the City's building standards,and other pertinent building regulations. a-3.Seismic-relatedground failure,including liquefaction? Less-than-Significant New Impact with Mitigation Incorporated.The California Seismic Hazard Zones,Palo Alto Quadrangle identifies the project area as being within a potential liquefaction hazard zone.During a major earthquake at one of the regional faults,violent groundshaking can result in ground failure due to liquefaction. Liquefaction is a transformation of soil from a solid to a liquefied state during which saturated soil temporarily loses strength resulting from the buildup of excess pore water pressure,especially during an earthquake.Lateral spreading,differential settlement,loss of bearing,ground fissures,and sand boils are evidence of excess pore pressure generation and liquefaction.Soil susceptible to liquefaction includes loose to medium dense sand and gravel,low-plasticity silt,and some low-plasticity clay deposits.According to the Geotechnical Investigation Report prepared by Kleinfelder(2006),investigations have historically encountered liquefiable soils on the project site. Areas susceptible to liquefaction also have high ground water levels (within 40 feet below ground surface [bgs]).As described in the 2007 FEIR(page 4.8-4),the groundwater level on the project site is expected to be at a depth of between 10 and 15 feet bgs.Based on the soil and groundwater conditions on the site,the potential for liquefaction is moderate. Mitigation Measure 4.8-2 (Mitigation Measure 4.8-2 in the 2007 FEIR [page 4.8-5]) requires the project to comply with liquefaction prevention measures. Implementation of this mitigation would be consistent with Program PS-23 in the General Plan and would reduce new seismic-related ground failure impacts to a less-than-significant level. Mitigation Measure 4.8-2 (2007 FEIR Mitigation Measure 4.8-2): The project shall comply with liquefaction prevention measures,as necessary,as stated within the State of California Mining and Geology Board Publication 117,"Guidelines for Evaluating and Mitigating Seismic Hazards in California." a-4.Landslides? No New Impact. Landslides and other slope failures are secondary seismic effects that are common during or soon after earthquakes.Areas that are most susceptible to earthquake-induced landslides are steep slopes underlain by loose,weak soils,and areas on or adjacent to existing landslide deposits.The project site is relatively flat and within a fully developed area.There are no steep slopes near the project site and the area is not included or adjacent to an earthquake-induced landslide zone. Hence,the project area has a very low probability for an earthquake-induced landslide to occur.As a result,implementation of the proposed modifications would not expose people or structures to substantial adverse effects involving landslides and no new impact would occur. b. Result in substantial soil erosion or the loss of topsoil? Less-than-Significant New Impact.As described in the 2007 FEIR(Appendix A,page 9),the project site is not located in an area where a high potential for soil erosion is present.A majority of the project site is covered with impervious surfaces which would allow for a very minimal erosion of topsoil. Due to the developed nature of the project site,construction activities associated with the Addendum No.2 to the Environmental Impact Report for 4-54 September 2012 the Redwood City Costco Wholesale Project ICF 00154.12