In this paper, we address some questions with respect to the Tianshan Mountains that are necessary for understanding the present deformation rate in this region. A series of thrust nappe structures are distributed on the north and south sides of the Tianshan Mountains, and many of them are currently active. To analyze the deformation characteristics and movement rates of different fold-and-thrust belts on the northern and southern margins of Tianshan, we use InSAR observations (Sentinel-1A/B, 2015–2020) to produce a rate map for the entire observation period on four ascending and four descending tracks. In order to reduce phase artifacts, we reconstruct multi-temporal scenes with atmospheric-corrected and orbital-corrected interferograms via a small baseline subset. The results show that the Bolokenu-Aqikekuduke Fault exhibits a right-lateral strike-slip motion, with the western segment moving at about 4.95 ± 0.38 mm/yr and the eastern segment at approximately 2.34 ± 0.34 mm/yr. The Manas-Tugulu anticline in the northern fold-and-thrust belt reaches ~5–8 mm/yr at 86°E–86.5°, and the Qiulitage anticline in the south reaches ~6–9 mm/yr at ~83°–85°. The post-seismic time series cumulative displacement map of the Jinghe earthquake reveals no significant post-seismic deformation signal in the epicenter area. The Qiulitage thrust belt, situated within the fold-and-thrust belts flanking the Tianshan, features extensive thrust accompanied by a right-lateral strike-slip component. And the Manas-Tugulu anticline exhibits sustained deformation, including pronounced coseismic and post-seismic effects from the Hutubi earthquake. This study highlights the potential of a multi-temporal InSAR analysis and emphasizes future opportunities presented by new generations of SAR platforms with shorter revisit periods for quantifying the spatial and temporal behavior of post-seismic and interseismic periods.

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.

Shanghai Pilot Free Trade Zone (SPFTZ) is the first free trade zone in China, consisting of eight independent zones and located in Pudong New District. With the rapid development in the SPFTZ, frequent human activities may induce severe land subsidence. Based on time-series interferometric synthetic aperture radar (InSAR) technique and multitemporal C-band images, the temporal and spatial evolution of subsidence in Pudong New District is obtained from May 2016 to October 2020. The achieved results show that severe subsidence occurred in the east of the study area, where the maximum subsidence rate was −40 mm / year. Most of the land in the SPFTZ remained stable, but small-scale subsidence with a maximum subsidence rate of −18.1 mm / year occurred in two zones. InSAR-derived results are in good agreement with the manual measurements, with a root mean square error of 1.4 mm. Time-series analysis reveals that land subsidence in the SPFTZ mainly originates from urban constructions, including building construction and vehicle load. Meanwhile, the most severe subsidence occurred in the east of Pudong International Airport, which may be attributed to the airport renovation project. In a reclaimed area, land subsidence can be classified into different construction periods, which gradually weakens from north to south.