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Deviation between velocity trajectories from global positioning system (GPS) networks and strain trajectories from earthquake focal mechanisms and fault-slip inversion within the central Walker Lane are reconciled as the consequence of non–plane strain (constriction) within a transtensional zone separating the Sierra Nevada and central Great Basin. Dextral transtension within the central Walker Lane is produced by differential displacement of the Sierra Nevada with respect to the central Great Basin, and it is partitioned into domains exhibiting simple shear–dominated and pure shear–dominated strain. From east to west across the central Walker Lane, GPS velocities change orientation from west-northwest to northwest and increase from 2–3 to 12–14 mm/yr as the incremental-strain elongation axis changes from west-northwest to west-southwest. The deviation between strain and velocity trajectories increases to 50° as the Sierra Nevada Range is approached from the east. This deviation in strain and velocity trajectories is consistent with analytical models linking kinematic vorticity, particle velocity paths, and incremental non–plane strain during transtensional deformation. We link field observations to the analytical models using a polar Mohr construction in a system that conserves kinematic boundary conditions to graphically demonstrate that the relationship between velocity and strain fields is a consequence of constrictional deformation.

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