This research is to develop a new technique for mapping the geometry and internal properties of fault zones by means of seismic waves travelling inside the low-velocity wave guide of the fault zone. For vertical faults such as the San Andreas, conventional seismic reflection and refraction techniques have not met with much success. The use of dispersive properties of trapped modes should lead to a better delineation of the fault zone, and a better understanding of the source rupture process and the process of earthquake occurrence. The work will consist of both field observations and theoretical modeling of the trapped modes. This research is a component of the National Earthquake Hazard Reduction Program.
