9316636 Chester This Research Planning Grant project will characterize the boundaries of rotated crustal blocks in the San Gabriel mountain, California, in order to better understand block rotation in major strike-slip fault zones. A preliminary field study will map brittle faults in the area to find the relationships among fault- slip, length and thickness. This preliminary study will be used to prepare a standard research grant proposal. In addition, the data will be used to make a tectonic reconstruction of the San Gabriel mountains region of southern California.