Block motions and strain partition on active faults in Northeast Tibet and their geodynamic implications

Abstract

AbstractAn updated GPS velocity field and set of focal mechanism solutions have allowed us to quantify the detailed tectonic deformation of Northeast Tibet. By employing block kinematic modelling, we show how the relative motion of modelled blocks is accommodated by deformation on major fault structures across the region, from the Eastern Kunlun Range to the Qilian Shan, with the slip rate decrease from the centre towards the east in the Kunlun, the Haiyuan and the Altyn Tagh Fault, as well as strain partitioning on these faults. The deflection of both the derived block strains and the focal stress from the west to the east also implies the strain transfer from the strike‐slip shearing to crustal shortening. Combining the different faulting regimes in each block with the distinctive distribution of the strain ratios, our results support a model of diffusive deformation associated with strain partition along tectonic boundary faults.