This research will investigate the 3-D seismic strain and stress as a function of distance along the San Andreas fault system. A moving average of the tensoral seismic strain field and state of stress will be computed using the existing seismic network data. Results will be related to detailed fault geometry, rates of creep, temporal and spatial proximity to earlier large earthquakes, and will be compared to numerical models of the fault. Preliminary results indicate that the principal compression is approximately normal to the fault where rates of creep are high, but oblique to the fault as creep falls off toward the north. Variation of tensoral strain components along the fault length appear related to fault ends, but also systematically change as a function of creep rate. This research is a component of the National Earthquake Hazard Reduction Program.
