9 First American Way - Soils Report

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Lutzky Associates Development. LP - Geotechnical Investigation MACTEC Project 4953-03-2631 September ] 8,2003 Los Alamitos Fault The potentially active Los Alamitos fault is located approximately 12 miles west-northwest of the site. This fault trends northwest-southeast from the northern boundary of the City of Lakewood, southeastward to the Los Alamitos Armed Forces Reserve Center. The fault, considered a southeasterly extension of the Paramount Syncline, appears to be a vertical fault with the early Pleistocene age materials on the west side of the fault displaced up relative to the east side. There is no evidence that this fault has offset Holocene age alluvial deposits (Ziony and Jones, 1989). Additionally, the State Geologist considers this fault to be potentially active (Jennings, 1994). Norwalk Fault The potentially active Norwalk fault is located about 12'/2 miles north-northwest of the site. The fault is a known ground-water barrier along the southern edge of the Coyote Hills, trending - southeasterly toward the Santa Ana Mountains. The fault is thought to be a north-dipping reverse oblique fault along which the Coyote Hills have been uplifted. This fault offsets lower Pleistocene age and older deposits near the mouth of the Santa Ana Canyon. However, there is no evidence that this fault has offset Holocene age alluvial deposits (Ziony and Jones, 1989). Additionally, the State Geologist considers the Norwalk fault to be potentially active (Jennings, 1994). 5.5 GEOLOGIC-SEISMIC HAZARDS Fault Rupture The site is not within a currently established Alquist-Priolo Earthquake Fault Zone for surface fault rupture hazards. The closest Alquist-Priolo Earthquake Fault Zone, established for the North Branch fault of the Newport-Inglewood fault zone is located approximately 7.4 miles southwest of the site. Based on the available geologic data, active or potentially active faults with the potential for surface fault rupture are not known to be located directly beneath or projecting toward the site. Therefore, the potential for surface rupture due to fault plane displacement propagating to the surface at the site during the design life ofthe project is considered low. 10