This research is an extension of an ongoing project to image the subsurface geometry of active faults associated with the San Andreas system in southern California. The geometry of mapped active faults will be found by pre-stack migration of existing seismic reflection datasets. The imaged faults will be related to regional deep crustal structures and tested for evidence of Poisson's ratio variations from amplitude-versus-offset trends, suggesting tectonically-active zones of weakness. Data from the EDGE and Calcrust projects will be used to investigate the Santa Maria Basin and Tehachapi Mountains areas. This research is a component of the National Earthquake Hazard Reduction Program.
