Laserfiche WebLink
City of San Leandro Alvarado Commerce Center Project <br /> 36 <br />According to the Geotechnical Report prepared by Cornerstone Earth Group in November 2016 <br />(included in Appendix A), the project site is not located in an Alquist-Priolo Earthquake Fault Zone <br />and there are no known faults crossing or projecting toward the site. The closest such zone is along <br />the Hayward Fault, approximately 2.1 miles northeast of the project site (Table 5). Therefore, <br />ground rupture due to faulting is unlikely at the site. No impact would occur. <br />Table 5 Approximate Fault Distances <br />Fault Name Distance (miles) <br />Hayward-Rodgers Creek 2.1 <br />Calavera 10.6 <br />Mount Diablo Thrust 13.9 <br />Source: Cornerstone 2016 <br />NO IMPACT <br />a.2. Expose people or structures to potential substantial adverse effects, including the risk of loss, <br />injury, or death involving strong seismic ground shaking? <br />a.3. Expose people or structures to potential substantial adverse effects, including the risk of loss, <br />injury, or death involving seismic-related ground failure, including liquefaction? <br />c. Would the project be located on a geologic unit that is made unstable as a result of the project, <br />and potentially result in on or offsite landslide, lateral spreading, subsidence, liquefaction, or <br />collapse? <br />The San Francisco Bay Area region is one of the most seismically active areas in the country. While <br />seismologists cannot predict earthquake events, the USGS’s Working Group on California <br />Earthquake Probabilities (WGCEP) estimates the likelihood that California will experience a <br />magnitude 8 or larger earthquake in the next 30 years is about 7.0 percent (Cornerstone 2016). The <br />WGCEP also estimates that each region of California will experience a magnitude 6.7 or larger <br />earthquake in the next 30 years. Additionally, there is a 63 percent chance of at least one magnitude <br />6.7 or greater earthquake occurring in the Bay Area region between 2007 and 2036. <br />The site is located in an area of relatively high seismic potential. The faults in the area are capable of <br />generating large earthquakes that could produce strong to violent ground shaking at the project <br />site. The active fault nearest the site is the Hayward fault, which is located approximately 2.1 miles <br />to the northeast (Cornerstone 2016). <br />The project site is also in a state-designated Liquefaction Hazard Zone (Cornerstone 2016). The <br />factors known to influence liquefaction potential include grain size, relative density, groundwater <br />conditions, effective confining pressures, and intensity and duration of ground shaking. Loose, <br />saturated, near-surface, cohesionless soils exhibit the highest liquefaction potential, while dense, <br />cohesionless soils and cohesive soils exhibit low to negligible liquefaction potential. Liquefaction at <br />the project site would likely result in settlement of the ground surface. Liquefaction could also result <br />in excessive settlement of improperly designed foundations and possible lateral spreading, which <br />could damage the new development. <br />According to the City’s 2035 General Plan EIR, most of San Leandro is not located atop unstable <br />geologic materials that are prone to subsidence, lateral spreading, or collapse (San Leandro 2016f). <br />The Geotechnical report did not identify such hazards for the project site. The report indicated that <br />333