Deep tectonic movement beneath the Northeastern Tibetan Plateau based on InSAR and GRACE

SUMMARY Active tectonic movements and surface deformation are observed in the eastern Tibetan Plateau. Understanding variations in crustal thickness and the deep Moho interface is crucial for elucidating the expansion of the Tibetan Plateau. This study utilizes InSAR to derive vertical surface deformation and applies loading corrections based on Green's function method. Additionally, satellite gravity data are used to separate hydrological and tectonic signals to infer changes in the Moho interface. Our results indicate that the regionally averaged loading effects, estimated using localized Green's functions, account for approximately 16.5 per cent of the InSAR-derived vertical displacement field. This contribution exhibits significant spatial variability, exceeding 100 per cent in regions with strong hydrological activity. The loading calculation is highly sensitive to Earth model: the relative difference between the load displacement obtained using the local Green's function and that obtained with an average Green's function reaches 48.2 per cent. After applying loading corrections, a more accurate Moho uplift rate of $- $8.2 ± 3.1 mm a−1 is obtained. The findings support the conclusion that the Moho interface rises in the southern region of the study area, with crustal thinning, while the Moho surface sinks in the northern region, with crustal thickening.