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The Mw 6.3 Yutian earthquake, occurred in northwestern Tibet on 25 June 2020, is one of the major events sequentially occurring in the region following the 2008 Mw 7.2, 2012 Mw 6.2, and 2014 Mw 6.9 earthquakes, and is of great significance for studying the tectonic activity and assessing future seismic hazards in the region. In this study, we used Sentinel‐1 Synthetic Aperture Radar images to retrieve co‐ and post‐seismic deformation and to investigate the coseismic rupture behavior of the fault and the mechanisms of postseismic deformation. Based on the slip models of recent four nearby major earthquakes, we explored the local stress evolution, triggering mechanism of the 2020 event and future regional seismic hazards. Postseismic modeling reveals that afterslip on fault patches surrounding the ruptured co‐seismic patches is the main mechanism responsible for the near‐field deformation, with the poroelastic rebound relaxation only accounts for maximumly 25% of the ground displacement and limited impact on the overall deformation pattern. The Coulomb failure stress changes (ΔCFS) suggest that the 2020 Yutian earthquake was inhibited by the 2008 Mw 7.2 earthquake but facilitated by the 2012 Mw 6.2 and 2014 Mw 6.9 earthquakes, resulting in an overall ΔCFS with a large lateral gradient on the 2020 fault. Stress concentrations on nearby major faults indicate increasing chances of seismic hazards in the eastern section of the Altyn Tagh fault at 82.8°E, the western section of the Guozha Co fault at 81.5°E and the entire section of the Ashikule fault. Plain Language Summary: The 2020 Mw 6.3 Yutian earthquake is one of the major events sequentially occurred following the 2008 Mw 7.2, 2012 Mw 6.2, and 2014 Mw 6.9 earthquakes in Yutian County. As large earthquakes result in stress perturbations altering regional seismicity, it provides great opportunity for studying the regional tectonic activity and assessing future seismic hazards. In this study, we investigated the coseismic rupture behavior of the 2020 earthquake and the mechanisms of postseismic deformation observed by radar observations. We also explored the local stress evolution, triggering mechanism of the 2020 event and future seismic hazards. Postseismic modeling indicates that afterslip is responsible for most of the near‐field deformation, with the poroelastic rebound effect contributing only a small portion. Earthquakes prior to 2020 have generated considerable stress perturbations with complex patterns which may have triggered the 2020 Yutian earthquake. Stress concentrations on nearby faults indicate that future attention should be paid in the eastern section of the Altyn Tagh fault at 82.8°E, the western section of the Guozha Co fault at 81.5°E and the entire section of the Ashikule fault. Key Points: The afterslip and poroelastic rebound mechanisms were examined to explain the observed postseismic deformationPrevious major events caused complex stress changes on the fault ruptured in 2020 with along‐strike gradients from positive to negativeStress concentrations on major nearby faults were calculated and future seismic hazards were evaluated [ABSTRACT FROM AUTHOR]

In July 2019, a series of seismic events, including a magnitude (Mw) 7.1 mainshock and Mw 6.4 foreshock, occurred in Eastern California. Studying these seismic events can significantly improve our understanding of the Eastern California tectonic environment. Sentinel-1A and ALOS-2 PALSAR images were utilized to obtain co-seismic deformation fields, including mainshock and foreshock deformation. The Okada elastic dislocation model and ascending and descending orbit results were used to invert the co-seismic slip distribution and obtain a co-seismic focal mechanism solution. Using ascending Sentinel-1A images, a time-series deformation was obtained for 402 d after the earthquake, and the deformation evolution mechanism was analyzed. The maximum uplift caused by the co-seismic mechanism reached 1.5 m in the line of sight (LOS), and the maximum subsidence reached 1 m in the LOS. For 402 d after the earthquake, the area remained active, and its deformation was dominated by after-slip. The co-seismic inversion results illustrated that California earthquakes were mainly strike-slip. The co-seismic inversion magnitude was approximately Mw 7.08. The Coulomb stress change illustrated that the seismic moment caused by the co-seismic slip was 4.24 × 1026 N × m, which is approximately Mw 7.06. This finding is consistent with the co-seismic slip distribution inversion results. [ABSTRACT FROM AUTHOR]

The extraction of high-accuracy co- and post-seismic deformation fields and inversions of seismic slip distributions is significant in the comprehension of seismogenic mechanisms. On 12 November 2017, a MW 7.3 earthquake occurred on the border between Iran and Iraq. To construct the co-seismic deformation field, Sentinel-1A synthetic aperture radar (SAR) images from three tracks were used. Based on a prior knowledge, least-squares iterative approximation was employed to construct the three-dimensional (3D) co-seismic deformation field. to derive a time series of 2D post-seismic deformation, the multidimensional small baseline subset (MSBAS) technique was use. Co-seismic deformation fields were asymmetric; the maximum relative displacement was nearly 90cm in the radar line-of-sight between two centers of co-seismic deformation. The 3D co-seismic deformation field showed southwestward horizontal motion and continuous subsidence-to-uplift variation from northeast to southwest. The two-dimensional (2D) post-seismic deformation time series showed a gradual decaying trend and good correspondence with the aftershock distribution. The main mechanism of post-seismic deformation was an afterslip of the post-seismic faults. We used the elastic half-space model to invert co-seismic deformation fields and obtain source parameters of the slip model. The maximum and average slips were 2.5 and 0.72 m, respectively. The average slip angle was 126.38° and the moment magnitude was MW 7.34. The results of this study will contribute to research on regional tectonic activities. [ABSTRACT FROM AUTHOR]