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Hana Japan Restaurant Project <br />Initial Study/Mitigated Negative Declaration <br />43 <br />May 2025 <br />The updated Geotechnical Report prepared for the proposed project included four borings <br />ranging from seven to 28.5 feet, the site includes shallow bedrock and thicker, clayey soils. <br />Based on the results of the borings, the Geotechnical Report concluded that the probability <br />of soil liquefaction within the project site is low.20 Thus, the proposed project would not <br />directly or indirectly cause potential substantial adverse effects, including the risk of loss, <br />injury, or death associated with seismic-related ground failure, including liquefaction. <br /> <br />Landslides <br />Seismically induced landslides are triggered by earthquake ground shaking. The risk of <br />landslide hazard is greatest in areas with steep, unstable slopes. The hillside located to <br />the southwest of the site is located within a preliminary State of California Seismic Hazard <br />Zone for areas that may be susceptible to seismically induced landsliding. However, the <br />Geotechnical Report notes that an existing driveway and 25-foot-wide setback zone would <br />be located between the potential landslide area and the proposed building.21 The <br />intervening area would serve as a debris catchment area in the event of a landslide. <br />Therefore, the proposed project would not directly or indirectly cause potential substantial <br />adverse effects, including the risk of loss, injury, or death involving landslides. <br /> <br />Conclusion <br />Based on the above discussion, the proposed project would not result in potential hazards <br />or risks related to seismicity, liquefaction, or landslides, and a less-than-significant <br />impact would occur. <br /> <br />b. Issues related to erosion are discussed in Section X, Hydrology and Water Quality, of this <br />IS/MND. As noted therein, the proposed project would not result in substantial soil erosion <br />or the loss of topsoil. Thus, a less-than-significant impact would occur. <br /> <br />c,d. The proposed project’s potential effects related to lateral spreading, <br />subsidence/settlement, and expansive soils are discussed in detail below. Impacts related <br />to liquefaction and landslides are discussed in question ‘aiii, aiv’ above. <br /> <br />Lateral Spreading <br />Lateral spreading is horizontal/lateral ground movement of relatively flat-lying soil deposits <br />towards a free face such as an excavation, channel, or open body of water; typically, <br />lateral spreading is associated with liquefaction of one or more subsurface layers near the <br />bottom of the exposed slope. The amount of movement depends on the soil strength, <br />duration and intensity of seismic shaking, topography, and free face geometry. Although <br />liquefaction is not expected to occur on-site, the project site is located adjacent to free <br />faces and, thus, the proposed project could be subject to risks associated with lateral <br />spreading. <br /> <br />Subsidence <br />Subsidence is the settlement of soils of very low density, generally from either oxidation <br />of organic material, desiccation and shrinkage, or both, following drainage. Subsidence <br />takes place gradually, usually over a period of several years, and is a common <br />consequence of liquefaction. As discussed above, the project site is not anticipated to be <br />subject to liquefaction. In addition, Section 5.4.7 of the Geotechnical Report concluded <br />that seismically induced settlement is unlikely. However, the Geotechnical Report also <br /> <br />20 ENGEO Incorporated. Geotechnical Report Update [pg. 10]. January 15, 2025. <br />21 ENGEO Incorporated. Geotechnical Report Update [pg. 10]. January 15, 2025.