Patterns of Strain Accumulation along Large-Scale Active Strike-Slip Fault Systems in Western and Northern Tibet

The collision between the Indian and Eurasian plates has led to significant strain accumulation not only within the Tibetan Plateau but also along its boundaries. However, along the western and northern boundaries of the Tibetan Plateau, several important scientific questions have not been clearly answered. First, previous geodetic and geological studies show an eastward decrease of slip rate along the central-eastern ATF, but the spatial variation of the slip rates and the mechanism causing such variation are uncertain. Additionally, interseismic deformation around the restraining bends along the ATF and its pattern of termination towards its eastern end are also unclear. Second, at the western end of the Altyn Tagh fault, due to a lack of high-resolution geodetic results, how the convergent motion between the India plate and the Tarim basin is accommodated by active faults is unknown. Third, in the northern Tibetan Plateau, the strain accumulation pattern along the Haiyuan fault system and Eastern Kunlun fault is uncertain. Specific questions, such as how the strain accumulation is terminated at the two ends of the Haiyuan fault system and if there is a viscoelastic relaxation signal associated with the 1920 Haiyuan earthquake within the geodetic velocity field, also need to be answered. To address all these questions, I produced large-scale high-resolution velocity fields and strain rate maps for the southwestern, northwestern and northeastern Tibetan Plateau, and provided geodetic constraints to the kinematics of major strike-slip fault systems, including the Altyn Tagh fault system, the Longmu-Gozha Co fault system, the Haiyuan fault system, the Karakoram fault and Eastern Kunlun fault. My results highlight the importance of the major active strike-slip faults in accommodating the strain generated by the collision between the Indian and Eurasian plates. The output from these studies will improve our understanding of these faults, and at the same time, provide valuable reference datasets and supports from geodetic observations.