Knowledge of the rates of strike-slip motion along plate boundary faults is important to late Cenozoic tectonism and to earthquake hazard reduction efforts. This project addresses the Septentrional fault zone in the Dominican Republic which is the active, on shore extension of the North American- Caribbean plate boundary. The work will focus on fault trenching at three Quaternary fault scarps combined with radiocarbon age dating. These data are expected to date the ages of past earthquakes along the fault and directly determine geologic slip rates. These results can be used to test conflicting plate motion models and can be integrated into ongoing marine geophysical survey and GPS experiments along the plate boundary.