Although faults are thought to be locked by friction during the intervening time between large earthquakes, a subset of continental faults that exhibit aseismic slip in the crust, known as shallow creep, have been documented with the aid of accurate geodetic data. This unusual slip behaviour may control the dynamic processes of earthquake rupture and can help illuminate fault physical properties. Therefore, it has attracted great attention in kinematic and dynamic studies of continental faults over the past decade. Previously, the Haiyuan fault is the only example in the Tibetan Plateau that has been found to exhibit steady-state shallow creep, i.e. creep rate equates to the tectonic loading rate. Our recent study has reported a new shallow creeping fault in the western Tibetan Plateau, the Gozha Co fault, and characterised its creeping rate and temporal evolution based on Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) data. In this paper, we investigate the Gozha Co fault in greater detail, including its three-dimensional kinematic features and geodetic moment accumulation using a Bayesian inversion approach. We collect JAXA's Advanced Land Observing Satellite-2 (ALOS-2) PALSAR-2 data acquired from 2014 to 2022, and derive a rate map covering the central-eastern section of the Gozha Co fault using the Small Baseline Subset (SBAS) method. The ALOS-2 rate map shows that strain is concentrated on the Gozha Co fault and the Longmu Co fault, part of the commonly called Longmu-Gozha Co fault system, has no measurable motion. We then take a velocity profile from the ALOS-2 and Sentinel-1 surface deformation maps to invert fault geometry and creeping rates in order to provide prior information for the subsequent three-dimensional kinematic inversions. Profile inversions show that the Gozha Co fault is a vertical (dip angle 88.1 degrees) left-lateral strike-slip fault (similar to 5 mm/a) with a small thrust component (<1 mm/a). Using these parameters as prior constraints, we derive the three-dimensional slip-rate distribution, which reveals spatial heterogeneity both down-dip and along-strike. Within the seismogenic depths (0-20 km), the Gozha Co fault is composed of a similar to 40-km-long highly locked segment in the west (slip rate less than 1.5 mm/a) and a similar to 100-km-long aseismic (creeping) segment in the east (slip rate 1.5-6 mm/a). Shallow creep rate increases from the west (partially creeping zone, similar to 2.8 mm/a) to the east (fully creeping zone, similar to 5.6 mm/a). The Gozha Co fault is located in a region with low P-wave velocity anomalies, which suggests decompression melting within the asthenosphere and magma upwelling, so one possible explanation for the shallow creeping behaviour is that deep fluid migration towards the surface affects crustal rheology and strength, resulting in low frictional strength of the fault. Based on the rate distribution, we estimate the seismic moment accumulation rate. The shallow creeping section has a fairly low seismic moment accumulation rate (similar to(3.3 +/- 1.9)x10(16) N m/a), consistent with its low seismicity level, so it is unlikely to generate large earthquakes. On the contrary, the highly locked section has a high moment accumulation rate (similar to(1.2 +/- 0.2)x10(17) N m/a), incompatible with the moment release by 1 <= M<6 earthquakes, suggesting that this section is capable of producing moderate to strong earthquakes. These new findings shed light on the kinematics of the Gozha Co fault and the style of present-day deformation in the northwestern Tibetan Plateau.
