Slip rates and seismic moment deficits on main active faults in Tianshan constrained by GNSS network

SUMMARY Tianshan Mountains in Central Asia are one of the largest and most active orogenic belts in the world, characterized by complex structures and strong seismic activity. In this paper, we use recently updated Global Navigation Satellite System data to self-consistently estimate the slip rates of major faults in Tianshan region via the elastic block model. Our results indicate that crustal deformation in Tianshan region is predominantly manifested as crustal shortening, regulated by foreland thrust belts and intermontane basin boundary faults. The shortening rate decreases from 14.2 ± 3.4 mm yr−1 in the west to approximately 3 mm yr−1 in the east. By estimating the seismic moment accumulation rates of the major seismic belts and comparing them with the historical earthquake catalogue, we identify six seismic belts with significant seismic moment deficits. This indicates a potential risk for earthquakes exceeding magnitude 7, including the Kash fault, Keping fault, the Maidan fault zone and the North Tianshan seismic belt. The Nalati seismic belt exhibits a relatively small seismic moment deficit, indicating the potential of earthquakes in the magnitude range of 6 to 7. In contrast, Qiulitage fault, the West Tianshan seismic belt and the Manas fold-and-thrust belt show a moment surplus, suggesting a low likelihood of strong earthquakes occurring in the near future. This study provides critical data and theoretical support for the prediction and risk assessment of seismic activity in Tianshan region.