Slip deformation along the Gyaring Co fault from InSAR and GPS

Interferometric synthetic aperture radar (InSAR) can monitor large-scale small deformation. Because the Sentinel-1 satellite has a stable orbit control and the data coherence in Qinghai–Tibet Plateau is good, we utilize data from Sentinel-1 to analyze the slip deformation of the Gyaring Co fault (GCF) in the central Tibetan Plateau. Data are obtained from ascending and descending tracks covering the research area, and the deformation results are obtained by the stacking and analysis of time series. The results demonstrate that the GCF exhibit slow slip overall. An analysis of different sections indicates that the fault displays both right-lateral strike-slip and normal faulting behaviors, and the movement is particularly obvious in the middle section of the GCF. Furthermore, we investigate the contemporary slip rate of the GCF using GPS data and construct two velocity profiles perpendicular to the fault strike at the southeastern and northwestern ends of the fault. The southeastern profile shows ~ 4 mm/year of right-lateral strike-slip movement and a modest (< 1 mm/year) amount of crustal thickening across the fault, while the northwestern profile shows much slower (~ 1 mm/year) right-lateral strike-slip motion and 0.5 mm/year of crustal extension. The GPS results are consistent with the InSAR deformation map derived using Sentinel-1 A/B data from 2014 to 2017. Our results support the distributed crustal motion model in which most crustal deformation (shortening/extension/strike-slip) occurs on various active faults in the central Tibetan Plateau rather than being concentrated on several fast-moving fault zones, e.g., the GCF-BCF. Finally, we analyze the distribution of historical earthquakes and the gravity and aeromagnetic fields. We speculate that a fault may exist north of Gyaring Co Lake that may be an extension of the fault north of Mujiu Co Lake.