9 First American Way - Soils Report

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Lutzky Associates Development. LP - Geotechnical Investigation MACTEC Project 4953-03-2631 September 18,2003 potential surface fault rupture hazard. However, the Northridge Thrust is an active feature that can generate future earthquakes. The vertical surface projection of the Northridge Thrust is about 46 miles northwest of the site at the closest point. The California Geological Survey (2003) estimates an average slip rate of 1.5 mm/yr. and a maximum magnitude of 7.0 for the Not-thridge Thrust. Potentially Active Faults Pelican Hill Fault The closest potentially active fault to the site is the Pelican Hill fault located approximately 5 mi|es to the northwest. There is evidence that several branches of the fault offset late Pleistocene age terrace deposits (Miller and Tan, 1976). The Pelican Hill fault is believed to be a probable branch of the Newport-Inglewood fault zone. Evidence presented by Tan and Edgington (1976) suggests that the Pelican Hill fault has displaced marine terrace deposits, suggesting late Pleistocene or younger activity. However, there is no evidence that this fault has offset Holocene age alluvial deposits (Ziony and Jones, 1989). Additionally, the "Fault Activity Map of California" published by the California Geological Survey (Jennings, 1994) considers this fault to be potentially active. El Modeno Fault The potentially active El Modeno fault is located about 8 miles north of the site. The fault is a steeply-dipping normal fault about 9 miles long and has about 2,000 feet of uplift on its eastern side. Movement on the fault has been inferred during Holocene time, suggesting the fault is active (Ryan et al., 1982). However, the State Geologist considers this fault to be potentially active (Jennings, 1994). Peralta Hills Fault The potentially active Peralta Hills fault is located approximately 8.5 miles northeast of the site. This reverse fault is about 5 miles long and generally trends east-west and dips to the north. Pleistocene age offsets are known along this fault; however, 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). 9