The PI will develop several numerical formulations for the purpose of studying fault-like behavior in viscous flow calculations, specifically applied to understanding the dynamics of subduction zones. he will compare formulations, including the formulations currently used in plate calculations, using observables such a gravity and topography profiles, stress distributions (in the plate and slab), compressional and extensional tectonic environments (e.g., formation of back arc basins or mountain belts), plate velocity and slab dip. This systematic comparison will not only highlight strengths and weaknesses of the various methods, it will call attention to features which are unique to one particular methods and may be an artifact of that method, not a robust characteristic of faulting. On the other hand, since each method is built on different set of assumptions, a comparison of approaches may lead to an understanding of unique signatures in the observables (e.g., topography and geoid profiles, slab dip, tectonic environment) which could be used to predict the dominance or absence of physical processes in specific subduction zones.
