Current methods for determining the slip vector or sense of shear for brittle fault zones of any age or seismic capability are largely based on the orientation of striations. Brittle fault zones lacking striations are difficult or impossible to analyze kinematically by these methods. The primary objective of this research is to test the general applicability of a new, symmetry-based method for stereographically and statistically determining the synoptic slip vector in non-striated fault zones. The model will be tested by measuring and analyzing Riedel structures and folds developed in the basal, gouge-filled shear zones of several Cenozoic to Recent landslides or rock avalanches in the southwestern US where the slip vector is known. Results will help validate a new method for determining slip directions in unstriated brittle faults which are common in nature.
