1901-1919 N Fairview St - Soils Report

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603284-001 3.0 GEOLOGIC/SEISMIC HAZARDS These hazards include surface faulting, ground lurching, seismic shaking, landslides, liquefaction, seismically-induced settlement, lateral spreading, seismically-induced landslides, flooding, expansive soils, and corrosive soils. The following sections discuss these hazards and their potential impact at the project site. 3.1 Faulting and Seismicitv In general, the primary potential seismic hazards for sites in the region include strong ground shaking and surface fault rupture. Our discussion of faults potentially impacting the site is prefaced with a discussion of California legislation and state policies concerning the classification and land-use criteria associated with faults. By definition of the California Geological Survey (CGS), an active fault is a fault that has had surface displacement within Holocene time (about the last 11,000 years). The state geologist has defined a potentiallv active fault as any fault considered to have been active during Quaternary time (last 1,800,000 years). This definition is used in delineating Earthquake Fault Zones (EFZ) as mandated by the AIquist-Priolo Earthquake Faulting Zones Act of 1972 and as most recently revised in 2007 (Hart, 2007). The intent of this act is to ensure that unwise urban development and certain habitable structures do not occur across the traces of active faults. Based on our review, the site is not located within an EFZ, (CGS, 2007). A Regional Fault Map (Figure 6) is attached to show the proximity of the site to major regional faults. Regional faults within approximately 100 kilometers of the site that are considered capable of producing significant seismic shaking are summarized in Table 2 below. The slip rates and maximum magnitude events are based on the statewide probabilistic seismic hazard assessment and the subsequent update report (CGS, 2003). -9- Leighton