Present day kinematics of the Eastern California Shear Zone from a geodetically constrained block model

We use Global Positioning System (GPS) data from 1993-2000 to determine hor izontal velocities of 65 stations in eastern California and western Nevada between 35 degrees and 37 degrees N. We relate the geodetic velocities to f ault slip rates using a block model that enforces path integral constraints over geologic and geodetic time scales and that includes the effects of el astic strain accumulation on faults locked to a depth of 15 km. The velocit y of the Sierra Nevada block with respect to Nevada is 11.1 +/- 0. 3 mm/yr, with slip partitioned across the Death Valley.. (2.8 +/- 0.5 mm/yr), Panam int Valley (2.5 +/- 0.8 mm/yr), and Airport Lake/Owens Valley (5.3 +/- 0.7/ 4.6 +/- 0.5 mm/yr) faults. The western Mojave block rotates at 2.1 +/- 0.8 degrees /My clockwise, with 3.7 +/- 0.7 mm/yr of left lateral motion across the western Garlock Fault. We infer 11 +/- 2 mm/yr of right lateral motion across the Mojave region of the Eastern California Shear Zone.