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S A N L E A N D R O G E N E R A L P L A N <br />E N V I R O N M E N T A L H A Z A R D S <br />7-4 <br /> <br /> <br /> <br />The major earthquake-related hazards in San Leandro are ground <br />shaking, ground failure, and liquefaction. These hazards tend to be <br />amplified on artificial fill and on deep alluvial soils like those found along <br />the Bay and old streambeds. Earthquake hazard maps prepared by the <br />Association of Bay Area Governments indicate that a large Hayward Fault <br />quake would trigger very strong shaking throughout the city and a high <br />risk of liquefaction in the Marina Faire/Mulford Gardens and Washington <br />Manor/Bonaire neighborhoods. <br />The California Geological Survey has designated the area immediately <br />adjacent to the Hayward Fault as a “Special Studies Zone.” Before any <br />development may occur within this zone, geologic studies are required to <br />determine the precise location of active fault traces and feasibility of <br />construction. Structures must be set back at least 50 feet from any fault <br />trace and must be engineered to reduce the potential for earthquake <br />damage. Elsewhere in the City, the California Building Code contains <br />specific requirements for structural design, foundations, grading, and <br />seismic loads, to reduce the potential for quake damage. <br />Figure 7-1 shows the location of the Hayward Fault and Special Studies <br />Zone, along with those areas identified as having the highest risk for <br />liquefaction in a major earthquake. <br />Structural Hazards <br />Enforcement of the California Building Code by the San Leandro Building <br />Department helps ensure that new construction will withstand the forces <br />associated with a major earthquake. However, many of the buildings in <br />San Leandro pre- date modern codes and are susceptible to damage. The <br />City has implemented a decades-long program to retrofit unreinforced <br />masonry buildings (URMs), most of which were located in and around <br />Downtown. With that hazard now substantially reduced, the focus has <br />turned to soft-story buildings, concrete tilt-up structures, and older single <br />family homes that could be seismically strengthened. <br />Resolution No. 2025-151 Exhibit A 4 of 84