## 3 Results
### Afterslip Model and Inversion  
As mentioned above, we successfully obtained the postseismic time series from the near-field, which provides a necessary foundation for the following study. In studying the physical mechanisms following the mainshock, we typically consider three factors: afterslip, viscoelastic relaxation, and poroelastic rebound, which influence postseismic deformation either independently or jointly [43; 51; 52]. However, during the early stages, the near-field transient postseismic deformation is consistently driven by afterslip [22; 32; 43; 53]. In this paper, we acquired the archived Sentinel-1A/B observations within 450 days after the mainshock, and the observed range is primarily concentrated in the near-field region, which indicates that the poroelastic rebound and viscoelastic relaxation have limited contributions to the observed displacements [35; 36]. Therefore, in this study, it is reasonable to assume that afterslip is the sole mechanism driving the near-field transient displacements in the early stages following the mainshock.  
We applied a fault geometry similar to the coseismic model but extended the fault to a depth of 50 km. Meanwhile, during the early stages, we further investigated the spatio-temporal evolution of afterslip following the mainshock. Our results indicate that the coseismic rupture was primarily distributed at depths of 0 to 15 km, consistent with other studies [8; 18; 20; 26]. Previous studies found that \(\Delta\)CFS triggered by the coseismic rupture is concentrated beneath the coseismic rupture [19; 22; 24]. This complies with the rate-strengthening conservative law. The coseismic zone is generally deemed to be a rate-weakening zone, where afterslip rarely occurs. Conversely, the zone with increasing Coulomb stress is considered a rate-strengthening zone where afterslip is generated [22; 24]. Therefore, the afterslip region is constrained to depths of 15-50 km in this study.  
The spatio-temporal InSAR measurements are beneficial for constraining the afterslip evolution, as shown in Figure 7. Spatially, F1 and F2 exhibit significant afterslip, while F3 and F4 show no obvious afterslip. On the segment F1, the afterslip during the 450 days following the mainshock is concentrated at depths between 20 and 35 km, with a maximum slip of approximately 0.3 m. On Segment F2, the afterslip during the same period occurs at depths ranging from 15 to 40 km, with a maximum slip of approximately 0.47 m. The released moment due to the afterslip reaches 4.57 \(\times\) 10\({}^{19}\) N\(\cdot\)m, corresponding to an Mw 7.04. Given that the time period of the InSAR data we used is similar to that used by [PERSON] et al., the released moment in our study shows slight differences compared to their findings [35]. The model predictions in the ascending and descending orbits also fit the observations well as shown in Figure 8.  
Figure 7: _Cont._Figure 8: The postseismic displacement observations (**a**,**d**), predictions (**b**,**e**), and residuals (**c**,**f**) for tracks 99 and 106 images over 450 days after this event. The red lines in (**b**) show the surface traces of the fault geometry. 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.  
Figure 7: The spatio-temporal evolution of aterslip on the fault plane (F1–F4) corresponds to the 12 snapshots of the InSAR observations in Figures 4 and 5. Each panel title denotes the observation time (in accumulated days) after this event. The legend is applicable to all other figures.