Abstract

Comprehensive quantification of the near-field deformation associated with an earthquake is difficult due to the inherent complexity of surface ruptures. The A.D. 2013 Mw 7.7 Balochistan (Pakistan) earthquake, dominated by left-lateral motion with some reverse component, ruptured a 200-km-long section of the Hoshab fault. We characterize the coseismic rupture in detail along its entire length. Optical and radar satellite images are combined to derive the full three-dimensional far-field displacement (115 m pixel size) and the high-resolution 2.5 m pixel horizontal displacement field resulting from the earthquake. We show that the vertical deformation is significant in several locations. The high-resolution near-field horizontal displacement (<1 km around the rupture) reveals inelastic shortening at the fault surface significantly larger than expected from simple elastic modeling. A zone of extension in the hanging wall, as much as 1 km wide, concentrating numerous tensile cracks visible in submeter-scale optical images, compensates for this excess shortening.

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