Dissipation of fast strike-slip faulting within and beyond northeastern Tibet

Recently published GPS measurements and Quaternary slip rates provide an opportunity to address how strike-slip faulting is accommodated and transferred at the northeastern margin of the Tibetan Plateau. Structural patterns, GPS velocities, and Quaternary fault slip rates indicate a transfer of left-lateral slip from the Kunlun fault northeast to the Haiyuan fault and minor crustal shortening and rotation within a 200 km wide step-over zone. Related deformation also continues at least a few hundred kilometers north of the Haiyuan fault into a region of diffuse extensional(?) shear or rotation underlain by average thickness crust. Fast, localized slip along the central Kunlun fault transforms into distributed deformation across a 500 km wide zone where the lower crust is weak. The difference in fault-parallel GPS velocities across this region also shows a decrease in fault slip toward the eastern fault tips and implies that discrete strike-slip motion does not extend east of the Tibetan Plateau. Thus, this pattern of deformation shows no evidence for extrusion of crustal blocks toward a lateral free boundary to the east, at least within Quaternary time.