Understanding earthquake physics is a critical step on the road to forecasting the short-term behavior of faults with obvious consequences for hazard mitigation. This is a project whose goal is to examine the dynamics associated with earthquake rupture. The studies to be carried out will provide much more comprehensive constraints on the way that a major fault zone behaves. Specifically, the project will combine detailed imaging of the San Jacinto Fault (SJF) in Southern California using an array to characterize the fault zone in the subsurface. It will couple this with surface outcrop and mapping of the fault zone, paleoseismic analysis, GPS analysis of crustal deformation, and theoretical work on seismic propagation to understand how factors such as fault damage, juxtaposition of different rock types, and segmentation affect the behavior of the fault zone. The Principal Investigators bring together current ideas about the rupture process and outline an approach that may be able to provide a quantitative understanding of the evolution of fault zone structures and related deformation phenomena (seismicity, strain fields) in actively deforming regions. This approach requires a framework that accounts for faults with evolving geometrical and material properties, as well as time-dependent interactions between the seismogenic zone and underlying viscoelastic substrate.
