## 3 Results
### Coseismic Model and Inversion  
Using a dislocation model, we assumed the fault plane is situated in an elastic half-space and further inverted the coseismic slip distribution [48]. We utilized the study of [PERSON] et al. [26] to set the fault parameters, dividing the fault geometry into four segments: F1 to F4 (Figure 5). F1, F2, and F3 were set to dip north with a dip angle of 80\({}^{\circ}\), while F4 dips 80\({}^{\circ}\) toward the south. The Poisson's ratio in the model was set to 0.25. At the same time, we divided the fault plane into 5 km \(\times\) 5 km sub-patches. Considering the left-lateral strike-slip characteristic of the seismogenic fault, we constrained the rake angle to vary from \(-30^{\circ}\) to \(30^{\circ}\). In order to increase inversion efficiency, the large volume of the InSAR dataset was downsampled [7]. We assigned the same weight to the ascending and descending datasets.  
Based on the Steepest Descent Method (SDM), we inverted the coseismic slip derived from the archived Sentinel-1 A/B images (Figure 5) [49]. The eastern part of the seismogenic fault exhibits a larger magnitude compared to its western section, and the rupture process is also shown to propagate bilaterally along the fault [50], suggesting that it may be an asymmetric bilateral rupture event. The coseismic slip distribution is concentrated at a depth of 0-15 km, with the peak slip occurring near the surface without significant weakening [8]. The maximum coseismic slip is approximately 4 m on the F2 segment, which is identified as the main seismogenic fault segment [8; 26]. Shallow slips are also concentrated in the eastern part of F1, the western part of F3, and the western part of F4. Four isolated asperities on the seismogenic fault demonstrate a complexity in frictional  
Figure 4: The InSAR time series derived from the ascending track within 450 days after the mainshock.  
properties. The released seismic moment is about 1.88 \(\times\) 10\({}^{20}\) N\(\cdot\)m, equating to a moment magnitude of 7.45, whereas the GCMT solution indicates a moment magnitude of 7.4. The InSAR-derived coseismic deformation may include contributions from aftershocks and early afterslip [21; 22]. Based on the relocated aftershocks [4] from 22 May 2021 to 26 May 2021, the total cumulative moment released by the aftershocks is estimated to be 2.476 \(\times\) 10\({}^{17}\) N\(\cdot\)m. Adding this value to the seismic moment provided by the GCMT (1.66 \(\times\) 10\({}^{20}\) N\(\cdot\)m), the total moment remains significantly lower than the estimated coseismic moment in this study. That is, the overestimated seismic moment may be attributed to the early postseismic effect mixed in the coseismic InSAR observations.  
The predicted coseismic surface displacement closely matches the actual InSAR observations (Figure 6c,f), but there are non-negligible residuals near the fault traces. These residuals may be attributed to unavoidable noise in the InSAR data processing and the potential complexity of the fault geometry or rupture process of the seismogenic fault. Refining the rupture process has always been challenging, but the inverted coseismic slip provides a means to describe the first-order features of the coseismic rupture. This contributes to further investigations into postseismic deformation mechanisms caused by coseismic stress release.  
Figure 5: The coseismic slip distribution of this earthquake. This study denotes the hypocenter as a blue star.  
Figure 6: The coseismic displacement observations (**a**,**d**), predictions (**b**,**e**), and residuals (**c**,**f**) for tracks 99 and 106 images. Bold black arrows represent the direction of the satellite’s flight, while red arrows indicate the LOS directions. The legend in (**f**) is applicable to all other figures. Red lines show the surface traces of the fault geometry.