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USGS Banner with Coachella Valley as seen from Keyes View in Joshua Tree National Park
Western Earth Surface Processes Team

San Andreas Fault System in the Inland Empire and Salton Trough

Right-Lateral Strike-Slip Faults of the Inland Empire

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San Jacinto Fault Zone
San Andreas Fault Zone

San Gabriel Fault
Banning Fault
Mission Creek Fault

In the vicinity of the central Transverse Ranges, rocks of Peninsular Ranges type, San Gabriel Mountains type, and San Bernardino Mountains type are traversed by a series of northwest-trending strike-slip faults (fig. 1) that most workers assign to the San Andreas transform-fault system a family of right-lateral faults that has evolved along the continental margin of western North America since middle Miocene time in response to interactions between the North American plate and various oceanic plates to the west (Atwater, 1970; Crowell, 1979; Dickinson and Snyder, 1979a,b). Youthful faults commonly viewed as modern components of the San Andreas system include the San Andreas fault proper; the San Jacinto, Whittier-Elsinore, and Newport-Inglewood faults; and various northwest-trending faults occurring in the offshore continental borderland (see Allen, 1957, p. 346; Crowell, 1975a, p. 10-11, 1981, p. 593). Older faults commonly viewed as abandoned components of the San Andreas system include the Punchbowl, San Gabriel, and Banning faults (Allen, 1957; Crowell, 1962, 1975a, 1981; Ehlig, 1976, 1981). Even older right-lateral faults that may belong to the San Andreas system include the San Juan-St. Francis and San Francisquito-Fenner-Clemens Well fault zones proposed in various forms by Smith (1977), Powell, (1981, 1986), and Joseph and others (1982b).

Right-lateral strike-slip faults in southern California are named and classified according to a hierarchical nomenclature that includes fault "strand", fault "zone", and fault "system" (Crowell, 1975a, p. 10-12): thus, the Mission Creek and Mill Creek strands (along with other fault strands) occur within the San Andreas fault zone that (along with other fault zones) occurs within the San Andreas fault system. Within this hierarchical classification, we adopt the fault nomenclature identified in Table 1 and map sheets 1 and 2.

Continue to the San Jacinto Fault.

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