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the site. These include the Midway, Antioch, and Greenville faults, which are located 57, 61, and 66 km west of the site, respectively. To estimate the MPE that may occur along each significant fault previously identified, the earthquake potential of each must first be evaluated. The historic earthquake record may be used to estimate the earthquake potential of faults. Historical seismicity within 100 km of the site was compiled (see Plate C-2) and indicates that the area surrounding the site is characterized by relatively low seismicity. Between 1800 and 1986, 19 significant historic earthquakes occurred within 100 km of the site. The nearest known significant historic earthquakes occurred 63 km west of the site, in the Northern Coast Ranges geomorphic province (see Plate C-2). Maximum historic earthquakes for previously identified faults are summarized on Table C-1. The maximum historic earthquake associated with the Greenville fault (magnitude 5.9) occurred in 1980, approxi- mately 63 km west of the site. The maximum historic earthquake associated with the Antioch fault (magnitude 6.0) occurred in 1889, approximately 70 km from the site. The maximum historic earthquake _ associated with the Melones fault zone (magnitude 4.0) occurred in 1937, approximately 116 km southeast of the site. Prior to 1975, the Sierran Foothills fault system (i.e., the Bear Mountains and Melones fault zones) was considered inactive. The 1975 Oroville earthquake (magnitude 5.7) occurred along a northern segment of the Sierran Foothills fault system and prompted a re-evaluation of the earthquake potential of this fault system. The results of this evaluation indicate that the fault system is capable of generating maximum earthquakes ranging in magnitude from 6.0 to 6.5 (Borchardt, et al., 1972; Woodward -Clyde Consultants, 1977). In addition to evaluating the historic earthquake record, the earth- quake potential of faults may be evaluated by applying empirical relationships that relate various fault parameters (e.g., fault length, fault type, etc.) to maximum credible earthquake (MCE)