Test of a method for recognizing unmapped seismogenic faults.
Access changed 5/24/11.
Using the seismo-lineament analysis method developed by Cronin (Gammill and others, 2004), I have attempted to locate Holocene faults in the Point Dume 7.5 minute quadrangle of the central Santa Monica Mountains, southern California. I projected the nodal planes from each of eight focal-mechanism solutions for earthquakes with reported epicenters within the Pt. Dume quadrangle to define their intersection with a digital elevation model (DEM) of the ground surface. The intersection of a nodal plane with the ground surface is termed a seismo-lineament. Mapping seismo-lineaments onto a DEM yielded specific fault-location hypotheses that can be tested in the field. Accessible outcrops and road cuts were examined along each seismo-lineament to look for evidence of faulting on planes that are approximately parallel to the nodal planes. Several previously unidentified potentially seismogenic faults have been identified in this study, indicating that the seismo-lineament method is useful.