Preliminary and interim Quaternary structural and stratigraphic evaluation of Cheviot Hills/Century City area including Beverly Hills High School and proposed Los Angeles County Metropolitan Transportation Authority subway locations, California

This presentation provides an "interim" update regarding analysis of new data, which both support and change conclusions by Kenney GeoScience (KGS) at the January 2013 AEG meeting and KGS report of 2012. Numerous recent site-specific geologic studies have been completed or are underway by various parties within the Century City/Cheviot Hills area including the Los Angeles County Metropolitan Transportation Authority (Metro). Metro completed a fault study in 2011 (PB Americas) that included potential subway station sites with one proposed location placing a subway tunnel beneath Beverly Hills High School (BHHS). The Beverly Hills Unified School District has completed a study of the Beverly Hills High School conducted by Leighton Consulting Inc. (LCI). The Beverly Hills Unified School District also retained LCI to conduct a preliminary fault evaluation at the El Rodeo Elementary School (north of the proposed eastern Santa Monica subway station site).

In addition, private parties have conducted a fault investigation study at 10000 Santa Monica Boulevard located between the BHHS and the proposed eastern Santa Monica subway station site (Feffer Inc., 2012). This study included a 300-foot long, approximately east-west trending fault trench to investigate potential faults mapped by PB Americas (2011) associated with their West Beverly Hills Lineament Fault Zone (WBHLFZ). It is our understanding that an additional fault study is currently being conducted for the Westfield Mall, but these data are no yet available.

BHHS retained Kenney GeoScience (KGS) to evaluate all the available data from these studies as they were completed with the purpose to better understand fault structure, stratigraphy and potential fault activity in the Century City area. PB Americas (2011) proposed that numerous "active" faults occur in the Century City area associated with the northeast-southwest trending Santa Monica Fault Zone along Santa Monica Boulevard and the northwest-southeast trending WBHLFZ. In addition, the California Geological Survey (CGS) proposed a location of long speculated WBHLFZ on their website prior to completion of any Century City subsurface studies. Based on re-analysis of all the existing data, it appears that the findings and conclusions of PB Americas (2011) report may have been at least partially "hypothesis" driven and their report conclusions did not discuss reasonable levels of uncertainty based on their data. Their data, which consists primarily of CPT and continuous cores provides ample ambiguity regarding location and activity level of local faulting especially if some local faults exhibit primarily strike-slip motion. As originally proposed by KGS (2012), faults originally identified by PB Americas (2011) as part of the WBHLFZ are actually associated with faulting along Santa Monica Boulevard (LCI, 2012). Contrary to previous findings by KGS (2012), new analysis indicates that faults possibly associated with the West Beverly Hills Lineament (WBHL) likely do exist and are located immediately east of the BHHS campus. New numerical soil stratigraphic age data by Earth Consultants International (ECI) and John Helms CEG in the area has essentially increased the age of the Benedict Canyon Wash Deposits as originated stated by KGS (2012). The recent analysis has provided additional evidence that faults located along Santa Monica Boulevard are primarily strike-slip as proposed by KGS (2012); however, and based on discussions with the CGS, it is uncertain whether this fault zone within the Cheviot Hills is primarily left- or right-lateral. However, the primarily strike-slip nature of the "Santa Monica Boulevard Fault Zone" continues to support earlier findings that this fault zone is an upper plate "secondary" system to the presumably basal left-lateral reverse Santa Monica Fault Zone (SMFZ). Hence, it is still proposed that the basal SMFZ may reside south of Santa Monica Boulevard and may be blind through the Cheviot Hills.

The tectonic and stratigraphic structure of the Century City (Cheviot Hills) region is very complex, and it is clear that insufficient data currently exists to clearly indicate which fault zones are active, what the tectonic role of the various identified faults are, the role of local uplift and folding, and what are the kinematics in the region in terms of the potential convergence of the Hollywood, Santa Monica, and Newport Inglewood (WBHLFZ) faults are. Based on the LCI studies within the BHHS property, it appears that no active faults occur within the footprint of the campus.

Dr. Kenney has over 20 years of professional experience working as a Geologist in the southwestern United States. Areas of expertise include fault hazard evaluation (paleoseismology), desert landscapes (alluvial fans, aeolian systems - dunes), basin scale stratigraphy (assists in groundwater studies), structural geology, stratigraphy, and neotectonics.

Miles Kenney earned a Bachelors in Science degree from San Diego State University in 1989 with a Geology Major and minor in Chemistry. He then worked for Leighton and associates for 5 years as a geotechnical geologist primarily involving numerous fault investigations of the Elsinore Fault Zone working with Dr. Tom Rockwell and taking a million sand cone density tests on various grading projects! From 1994 to 1999 Miles completed his doctorate degree at the University of Oregon working with Dr. Ray Weldon. His dissertation involved the evaluation of the subsurface structure of the San Andreas, San Jacinto and Cucamonga fault zones in the San Gabriel Mountains. After receiving his PhD, Miles then worked for Earth Consultants for over a year then began teaching at San Diego State University and various community colleges in San Diego County. From 2002 to 2009 Dr. Kenney worked at Petra Geotechnical as their fault hazard specialist managing numerous fault investigation studies in southern California. From 2009 to the present time he has worked as an independent Geologic consultant via Kenney GeoScience. Recent projects have involved structural evaluation of Basin and Range structure in the Mojave Desert for groundwater storage projects (Cadiz Groundwater and Storage Project), fault and stratigraphic evaluation of the Cheviot Hills, evaluation of sand dune systems regarding dust emissions and preservation of habitat (numerous solar energy projects and the Los Angeles Department of Energy and Power).