The West Bullion-Mesquite Lake Fault step-over: Assessment and comparison with faults of the Eastern California Shear Zone, Twenty-Nine Palms Marine Corps Base, California
The purpose of this investigation was to determine where active fault strands exist within the West Bullion Fault-Mesquite Lake fault step-over, and to ascertain whether or not these would pose a threat to new building additions at the Twenty-Nine Palms Marine Corps Base, in California. During the summer of 2011, the Naval Facilities Engineering Command (NAVFAC) proposed three new buildings to be added to the base. This would include a Quality of Life Center consisting of a bachelor enlisted quarters and dining facility located at the northern portion of the base, along with a child development center at the southernmost part of the base (Figure 1). Because the region is crossed by numerous mapped fault strands and lies in close proximity to the 1999 Mw 7.1 Hector Mine earthquake rupture, NAVFAC thought it necessary to conduct geotechnical investigations of the area. As a student hire for NAVFAC, I conducted a morphotectonic analysis of the base using aerial imagery and topographic data in Google Earth to map the location of potentially active faults expressed in the geomorphology. The overall purpose of this investigation is to assure that no new building structures will be constructed atop faults that may produce rupture in the future, thus reducing hazardous conditions to those who would be occupying the buildings. Therefore, towards that end, I then compared my geomorphic observations on fault locations with other known information about the West Bullion and Mesquite Lake faults to determine whether any of these faults within the step-over may pose a threat to proposed or existing structures on base.
