Interseismic strain rate distribution model of the Altyn Tagh Fault constrained by InSAR and GPS

The Altyn Tagh Fault (ATF) plays a pivotal role in determining the structural deformation patterns of the Tibetan Plateau. However, our current understanding of present-day slip characteristics of the ATF remains limited by a lack of high-resolution geodetic observations. In this study, we employed ascending and descending InSAR data from Sentinel-1, combined with GPS observations, to construct a high-resolution three-dimensional (3D) crustal deformation field covering the entire ATF. We calculated the strain rates, slip rates, rigidity contrast, and interseismic coupling across the ATF based on spatially dense crustal deformation. Our findings have shown that shear strain rates gradually decrease from the western to the eastern extent of the ATF. The western end exhibits shear extension that extends toward the Guozha Co. Fault, whereas the eastern end manifests shear compression toward the Changma Fault. The consistent slip rates in the central segments, decreasing at both terminations, suggest limited eastward material movement within the northern Tibetan Plateau along the ATF. Our geodetic data substantiate the "Limited Extrusion Model" for the Northern Tibetan Plateau. The inversion results from the half-space model indicate that the observed asymmetric interseismic strain across the ATF results from a combined effect of decreased rigidity from the Tarim Basin to the Tibetan Plateau and a southward horizontal offset. Our research underscores the inherent seismic risk of the ATF, with most segments exceeding Mw6.5. The Xorkoli and Aksay segments (S10-S13) are areas with the potential to generate earthquakes surpassing magnitude Mw7.5.