9 First American Way - Soils Report

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Lutzky Associates Development, LP - Geotechnical Investigation MACTEC Project 4953-03-2631 September ]8.2003 on the southeast to the Merced Hills, and possibly beyond, on the northwest. The main fault trace is a high-angle reverse fault, with the north side uplifted over the south side at an angle of approximately 70 degrees. In the Brea-Olinda Oil Field, the Whittier fault displaces Pleistocene age alluvium, and Carbon Canyon Creek is offset in a right lateral sense by the Whittier fault. Yerkes (1972) estimates vertical separation along the fault zone on the order of 1,800 to 3,600 meters, with a right slip component of about 4,600 meters. Elsinore Fault Zone The active Elsinore fault zone is approximately 15'/2 miles northeast of the site. This fault zone extends south-southeastward at least 110 miles along the northeastern flank of the Santa Ana Mountains. The fault zone dips steeply toward the southwest and displacement is both right-lateral and reverse-dip separation. The fault zone contains several parallel to subparallel fault segments, and characteristically occupies a trough-like depression. Palos Verdes Fault Zone Studies by Stephenson et al. (1995) indicate that there are several active on-shore splays of the Palos Verdes fault zone. Based on this study, which included geophysical studies, aerial photograph interpretation, and limited fault trenching, the nearest splay of the active Palos Verdes fault zone is located about 16'/2 miles southwest of the site. Based on geophysical data, the dip of the fault is interpreted to be near vertical to 55 degrees to the southwest (Stephenson et al., 1995). Vertical separations up to about 1,800 meters occur across the fault at depth. However, strike-slip movement is indicated by the configuration of the basement surface and lithologic changes in the Tertiary age rocks across the fault. Geophysical data also indicate offset at the base of the offshore Holocene age deposits (Clarke et al., 1985). The Palos Verdes fault zone is considered active by the State Geologist. However, no historic large magnitude earthquakes are associated with this fault. San Andreas Fault Zone The active San Andreas fault zone is located about 45 miles northeast of the site. This fault zone, California's most prominent geological feature, trends generally northwest for almost the entire length of the state. The southern segment of the fault is approximately 450 kilometers long and extends from 6