Growth of lithosphere-scale fault system in NE Tibet: Numerical modeling constrained by high-resolution seismic reflection data

The east Kunlun fault is an important strike-slip shear zone to understand continental deformation in NE Tibet. The recent high-resolution deep seismic reflection profiling across the Kunlun fault reveals a thrust fault system and two decollements in the crust, along with another thrust fault system which reaches to the depth of upper mantle and cuts off the Moho. The mechanism of the growth of these shear zones at lithosphere-scale, which reveals the type of deep deformation, is investigated using the finite-element method with an elastic-plastic constitutive relationship. The results show that the thrust fault system in the crust may be explained by the conjugated plastic deformation belts under compression from the Indian plate. The pre-existing fault in the depth may develop to cut the Moho toward two new directions rather than along the original direction. The vertical and lateral heterogeneity of material, frictional property and geometry of the models all affect the feature of the fault growth. The growth of the thrust fault system on both sides of the Kunlun fault is only located in the crust, it means that the Kunlun fault does not reach to the Moho depth.