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Central Valley Coast Range Fault The Central Valley Coast Range Fault(CRCV) is the eastern boundary of the coast range faults and is a subject of ongoing controversy for seismic hazard. The CRCV fault is a blind thrust fault. That is, there is no surface trace of the fault. Therefore, its location is uncertain. The activity rate of this fault is also highly uncertain. Since the CRCV is the eastern boundary of the Coast Range faults, it is the closest to the site of any of the coast range faults. Recently, EBMUD has conducted a hazard study for a pipeline in the Sacramento Delta (Foott, 1994) and as part of this study,we have reviewed the current estimates of the location of the CRCV. The best estimate location of the CRCV puts it about 46 km west of the North County site and dipping to the southwest (away from the site). The seismic source of the April 19, 1892 Winters Earthquake, M=6.4 (Toppozada, 1981) is not well constrained. It may be associated with the northern extension of the CRCV fault. For this study, I have assumed that the Winters Earthquake occurred along the CRCV fault. This is a conservative assumption,but I think that it is reasonable given the current uncertainty about the CRCV fault. Using the CDMG definition, the MPE for this fault is defined by the historical earthquake;magnitude 6.4. The recommended MME is a magnitude 6.4 earthquake at a closest rupture distance of 46 km. Greenville-Marsh Creek-Arroyo Fault The Greenville fault is part of the Greenville-Marsh Creek-Arroyo fault system has primarily strike-slip motions and extends for a total length of 70 km. The Greenville- March Creek segment is located 62 km west of the site. The largest historical earthquake for this fault system was the 1980 magnitude 5.8 earthquake that occurred on the Greenville-March Creek segment. The MPE for this fault is defined by the historical earthquake; magnitude 5.8. The recommended MPE is a magnitude 5.8 earthquake at a distance of 62 km. i 3 Z