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603284-001 <br />3.1.1 Surface Rupture <br />Our review of geologic literature pertaining to the site and general vicinity <br />indicates that there are no known active faults on or in the immediate <br />vicinity of the site (CGS, 2007). The nearest known active-zoned fault is <br />the Newport Inglewood (L.A. Basin) fault zone (NIFZ). The NIFZ is an <br />active northwest-trending, approximately 2- to 4-mile-wide belt of anticlinal <br />folds and faults disrupting early Holocene to Late Pleistocene age and older <br />deposits (Barrows, 1974). There is abundant seismic evidence that the <br />zone is tectonically active; thus, the surrounding metropolitan area is <br />subject to certain seismic risks. At least five earthquakes of magnitude 4.9 <br />or larger have been associated with the NIFZ since 1920 (Barrows, 1974). <br />Due to the lack of known active faults on the site, the potential for surface <br />rupture at the site is considered low. <br />3.1.2 Historical Seismicitv <br />Although Southern California has been seismically active during the past <br />200 years, written accounts of only the strongest shocks survive the early <br />part of this period. Early descriptions of earthquakes are rarely specific <br />enough to allow an association with any particular fault zone. It is also not <br />possible to precisely locate epicenters of earthquakes which have occurred <br />prior to the twentieth century. <br />A search of historical earthquakes was performed using the computer <br />program EQ Search (Blake, 2000) for the time period between 1800 and <br />1999. Within that time frame, 1,002 earthquakes were found within a 62- <br />kilometer (100-mile) radius of the Site. Of these earthquakes, the closest <br />epicentral location was 2.6 miles (4.2 kilometers) north of the site and <br />occurred on May 22, 1902 (Appendix D, Seismic Hazard Analysis). The <br />causative fault is unknown; however, it registered a 4.3 moment <br />magnitude (Mw) and induced recorded peak ground acceleration (PGA) of <br />0.131 g. <br />The largest recorded PGA at the site is estimated to be 0.210g from a <br />magnitude 6.3 earthquake referred to as the Long Beach earthquake that <br />shook the coastal region on March 11, 1933. Reported damage from the <br />Long Beach earthquake represents the most dramatic example of the <br />consequences of disregarding seismic hazards associated with the NIFZ. <br />-11- <br />Leighton