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Administrative Draft Environmental Impact Report Gill Medical Center Project Fault Rupture A fault rupture occurs when the surface of the earth breaks as a result of an earthquake, although this does not happen with all earthquakes. These ruptures generally occur in a weak area of an existing fault. Ruptures can be sudden (i.e. earthquake) or slow (i.e. fault creep). The Alquist-Priolo Fault Zoning Act requires active earthquake fault zones to be mapped and it provides special development considerations within these zones. The Project site does not have surface expression of active faults and fault rupture is not anticipated. Liquefaction Liquefaction typically requires a significant sudden decrease of shearing resistance in cohesionless soils and a sudden increase in water pressure,which is typically associated with an earthquake of high magnitude.The potential for liquefaction is highest when groundwater levels are high, and loose, fine, sandy soils occur at depths of less than 50 feet. Soil data from the NRCS Web Soil Survey suggests that the potential for liquefaction is low given that the soils are clayey and the water table is approximately 35 to 40 feet below the ground surface. Lateral Spreading Lateral spreading typically results when ground shaking moves soil toward an area where the soil integrity is weak or unsupported, and it typically occurs on the surface of a slope, although it does not occur strictly on steep slopes. Oftentimes, lateral spreading is directly associated with areas of liquefaction. Since the potential for liquefaction is low to moderate, the potential for lateral spreading is present.The General Plan Draft EIR indicates that with adherence to existing compliance with local building codes and ordinances would avoid or reduce hazards relating to unstable soils and slope failure., the potentially significant impact would be reduced to a less than significant impact. Landslides Landslides include rockfalls, deep slope failure, and shallow slope failure. Factors such as the geological conditions, drainage, slope, vegetation, and others directly affect the potential for landslides. One of the most common causes of landslides is construction activity that is associated with road building (i.e., cut and fill).The Project site is essentially flat;therefore, the potential for a landslide in the Project site is non- existent. Impacts related to the above are less than significant with adherence to adopted General Plan policy. Mitigation Measures None Required. Impact 4.9-2: The proposed project could result in soil erosion or the loss of top soil. Impact Determination: less than significant Threshold: Substantial soil erosion or the loss of topsoil. Geology and Soils 4.9-8 October 2021