Large‐Scale Extensional Strain in Southern Tibet From Sentinel‐1 InSAR and GNSS Data

In this study, we utilize C‐band Sentinel‐1 radar images from 2015 to 2022, combined with interseismic horizontal GNSS velocities, to construct large‐scale, high‐resolution, 3‐D velocity and strain rate maps over a vast region of southern Tibet. We show the distribution of prevailing dilatational strain accumulation along the seven major rift zones. Using 2‐D elastic dislocations invoking a two‐fault model in a Bayesian framework, we quantified the decadal extension rates across the seven rift zones, and we suggest a total extension rate of 18.4 ± 1.7 mm/yr, consistent with geological and geodetic estimates. The resulting strain rate maps, combined with the earthquake catalog, help us identify areas with high earthquake potential. Our study enhances our understanding of the present‐day tectonics and kinematics in southern Tibet and provides important constraints for seismic hazard assessment in this region. Plain Language Summary In this research, we used satellite radar images from 2015 to 2022 and GNSS data to study the crustal deformation and strain distribution in southern Tibet, where the Earth's crust is actively stretching due to the collision of the Indian and Eurasian plates and the extrusion of crustal materials. By analyzing high‐resolution 3D velocities, we provided new high‐resolution surface strain maps over southern Tibet. We found that the widespread dilatational strain is mainly localized along seven major N‐S trending rift zones. Seven major rift zones are experiencing extension at a total rate of 18.4 ± 1.7 mm/yr. The strain rate maps, combined with historical earthquakes, helped us identify fault segments that are more likely to host earthquakes in the future. By mapping deformation and strain in greater detail, we provided valuable data that can improve our understanding of kinematics and earthquake risk assessments in geologically complex southern Tibet. Key Points We present InSAR‐based, high‐resolution maps of 3‐D velocities and strain rates in Southern Tibet There is prevailing dilatational strain along seven rift zones in Southern Tibet, with a total extension rate of 18.4 ± 1.7 mm/yr We show the distribution and spatial variations of extension rates for seven rift zones