Refined kinematics of the Eastern California shear zone from GPS observations, 1993-1998

Global Positioning System (GPS) results from networks spanning the Eastern California shear zone and adjacent Sierra Nevada block, occupied annually b etween 1993 and 1998, constrain plate margin kinematics. We use an elastic block model to relate GPS station velocities to long-term fault slip rate e stimates. The model accounts for elastic strain accumulation on the San And reas fault, as well as faults of the Eastern California shear zone. South o f the Garlock fault, 14 mm/yr of dextral shear is distributed across the Ea stern California shear zone. Some of this slip penetrates eastward into the Basin and Range, and a collective budget of 13 mm/yr is observed to the no rth at the latitude of Owens Lake. Model slip rates for two important fault s, the Garlock and Owens Valley faults, significantly misfit geologic estim ates. By referencing station velocities to stable North America we observe northward-increasing deformation east of our regional GPS network. At the l atitude of Mojave Desert, however, some of this deformation is ascribed to elastic strain accumulation due to a locked San Andreas fault and thus does not represent additional fault-related, permanent deformation.