Brief Report for Elsinore fault zone, Whittier section (Class A) No. 126a
citation for this record: Treiman, J.A., and Lundberg, M.Matthew, compilers, 1998, Fault number 126a, Elsinore fault zone, Whittier section, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, http://earthquakes.usgs.gov/hazards/qfaults, accessed 07/29/2014 10:46 AM.
|Synopsis||General: A major dextral strike-slip fault zone that is part of the San Andreas fault system. The sections defined here of the Elsinore fault zone, from north to south: Whittier section [126a], Chino section [126b], Glen Ivy section [126c], Temecula section [126d], Julian section [126e], Coyote Mountain section [126f], and Laguna Salada section [126g]. Research studies have been done to assess faulting on most of the sections, and have documented Holocene activity for the length of the fault zone with a slip rate around 4-5 mm/yr. Multiple events have only been dated on the Whittier fault and Glen Ivy North fault strand, so interaction between faults and adjacent sections is not well-known. Multiple strands within several sections mean that the studies are not always fully representative of the whole section. Numerous consulting reports (not summarized herein) that have addressed location and recency of faulting are on file with the State of California, California Geological Survey, as part of the records of their Alquist-Priolo Earthquake Fault Zoning Program.|
Sections: This fault has 7 sections. Sections are selected following the segmentation from Working Group on California Earthquake Probabilities (1995 #4945) with addition of Laguna Salada section as used by Petersen and others (1996 #4860) and Chino fault (paired with the Whittier fault by Rockwell and others, 1992 #6431).Anderson and others (1989 #6372) also identified same segments, with addition of Chupamiertos and Sierra Mayor segments in Baja California (not included in this summary); Wesnousky (1986 #5305) defined four segments, combining the Whittier, Chino and Glen Ivy into his segment A, Temecula into segment B, Julian into segment C, and the Coyote Mountain and Laguna Salada sections into segment D.
|County(s) and State(s)||ORANGE COUNTY, CALIFORNIA |
LOS ANGELES COUNTY, CALIFORNIA
|Physiographic province(s)||PACIFIC BORDER |
|Length (km)||This section is 36 km of a total fault length of 306 km.|
|Average strike||N70°W (for section) versus N51°W (for whole fault)|
|Sense of movement||Dextral|
|Most recent prehistoric deformation||Latest Quaternary (<15 ka)|
|Slip-rate category||Between 1.0 and 5.0 mm/yr|
|Date and Compiler(s)||1998|
Jerome A. Treiman, California Geological Survey
Matthew Lundberg, California Geological Survey