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2. Seismic Hazard <br />C:\TRICH\Jobs\4515582 Leprino Tracy\Report\Leprino Tracy CalARP 040221.docx 2-2 <br />Geological Survey (CGS). Three such faults have been identified within a roughly <br />10-mile radius of the Leprino site: the Vernalis Fault, which passes as close as 2.0 miles <br />northeast of the site; the Midway Fault, whose trace passes as close as 7.5 miles <br />southwest of the site; and the Black Butte Fault, whose northernmost extent lies <br />approximately 7 miles south of the site. These faults are considered “inactive” (i.e., not <br />displaying evidence of surface displacement within Holocene time) by the CGS, a <br />threshold that would trigger evaluation under the Alquist-Priolo Earthquake Fault Zoning <br />Act. <br />The CalARP guideline (Reference 2) recommends the 2016 California Building Code <br />(CBC) (Reference 4) be used for determining the seismic hazard at the site. The current <br />CBC is based on the 2015 International Building Code (IBC) (Reference 7), which is in <br />turn based on the 2010 edition of ASCE 7 (ASCE 7-10) (Reference 6). The previous <br />evaluation utilized the 2013 CBC, which is also based on ASCE 7-10. <br />This report utilizes the Maximum Considered Earthquake (MCER) Spectral Contour <br />Maps developed for the 2016 CBC and ASCE 7-10 with a target risk of structural <br />collapse equal to 1% in 50 years. The Design Basis Earthquake (DBE) ground motion <br />spectrum to be used for evaluation is to be taken as two-thirds of the MCER values after <br />the MCER values have been adjusted for soil effects. <br />The seismic hazard parameters developed for the Tracy facility, using the 2016 CBC <br />approach are summarized below and presented in Appendix C. <br />Ss = 1.429 (mapped MCER spectral response acceleration parameter at short <br />periods) <br />S1 = 0.475 (mapped MCER spectral response acceleration parameter at a period of <br />1 sec.) <br />SDS = 0.953 (design spectral response acceleration parameter at short periods) <br />SD1 = 0.483 (design spectral response acceleration parameter at a period of 1 sec.) <br />PGA = 0.541 (peak ground acceleration) <br />A comparison of the above values with those used in the previous evaluation is <br />summarized in Table 2-2.