9316513 Shaw This research is to study earthquake complexity and the physics that can result in that complexity. The questions bear directly on where and how often earthquakes occur and on the nature of their damaging motion. In particular, a class of models is investigated where all of the complexity is generated by a frictional instability. Here, distributions of interesting quantities are produced, without distributions of any quantities having to be assumed. Results from the modeling studies will be compared with laboratory faulting studies and with the real earthquake record. This research is a component of the National Earthquake Hazard Reduction Program. ***