## 2 InSAR Coseismic Deformation and Postseismic Time Series
### Coseismic Observations and Deformation  
Using the differential InSAR (D-InSAR) technique, we analyzed the characteristics of coseismic deformation. The archived Sentinel-1A/B acquisitions were obtained in Terrain Observation by Progressive Scan (TOPS) mode, which requires precise co-registration. Therefore, to ensure the co-registration accuracy, we employed intensity matching and enhanced spectral diversity methods [38]. During InSAR data processing, we primarily utilized the Digital Elevation Model (DEM) to eliminate topographic phase. The Shuttle Radar Topography Mission (SRTM) DEM, acquired by the American Space Shuttle in 2000, covers 80% of the world's landmass. Additionally, NASA's publicly available 1 arc-second spatial resolution SRTM was used for further improving the co-registration accuracy of the Single Look Complex (SLC) pairs [39,40]. Before phase unwrapping based on the minimum cost flow algorithm [41], the Goldstein adaptive filtering method was applied to remove high-frequency noise [42]. Finally, we selected a multilook factor of 10:2 for the interferograms to improve the signal-to-noise ratio (SNR) [6].  
Figure 2 shows that the interference fringes and coseismic displacements derived from both ascending and descending observations. The interference fringes from the ascending and descending tracks are approximately symmetrical on both sides of the surface traces. Meanwhile, for the unwrapped coseismic deformation, there are clear discrepancies along the LOS direction: the south side moves toward the descending track satellite and far away from the ascending track satellite [23], while the opposite is true for the north side. Therefore, these findings reveal that the event may be dominated by a sinistral strike-slip motion on a near-vertical fault plane [20,22,23] (Figure 2a,c). The maximum coseismic displacement in the ascending observations is approximately 0.97 m on the north of the surface traces, whereas the descending observations show about \(-0.79\) m at the same location along the LOS direction, consistent with [PERSON] et al. [20]. High gradients in near-field deformation and/or serious surface damage result in phase decorrelation, suggesting that this event caused substantial destruction to the Earth's surface along the surface traces [23].  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Usage** &
\begin{tabular}{c} **Date** \\ **(yyyymmdd)** \\ \end{tabular} & **Track Number** & **Frame** & **Azimuth Angle (\({}^{\circ}\))** & **Number of SAR Images** \\ \hline Coseismic & 20210520-20210526 & 106 & 474–479 & \(-\)166.97 & 2 \\ Deformation & 20210520-20210526 & 99 & 1290–1295 & \(-\)12.89 & 2 \\ \hline Postseismic & 20210526-20221205 & 106 & 474–479 & \(-\)166.97 & 63 \\ Deformation & 20210526-20220819 & 99 & 1290–1295 & \(-\)12.89 & 38 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Detailed Information about the Archived Sentinel-1 A/B Images Utilized Herein.  
Figure 2: The original interferograms and the coseismic displacements. Bold black arrows represent the direction of the satellite’s flight, while red arrows indicate the LOS directions. Panels (**a,b**) display the interferogram and coseismic displacements of the descending track, respectively; panels (**c,d**) indicate the interferogram and coseismic displacements of the ascending track, respectively.