## 2 Materials and Methods
### PS-InSAR Processing  
The Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) technique was applied to extract time-series ground deformation data from the SAR imagery. PS-InSAR identifies stable reflectors, typically man-made structures such as railway tracks, bridges, and buildings, which maintain high coherence across multiple SAR acquisitions. This methodology is based on well-established principles described in previous studies [15; 16; 19], which demonstrate the capability of PS-InSAR to detect millimeter-level displacements by analyzing the phase stability of persistent scatterers over time. Figure 1 illustrates the PS-InSAR processing flowchart, detailing the sequential steps involved in the analysis. The PS-InSAR processing workflow was as follows:  
1. Co-registration--All SAR images were geometrically aligned to a master scene to ensure pixel-level correspondence throughout the stack [16]. 2. Interferogram Generation--Interferograms were created for each SAR interferometric pair, calculating phase differences attributable to surface displacement while minimizing temporal and spatial decorrelation effects [20]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**29 Images (TerraSAR-X: 24, TanDEM-X: 5)** & & & & \\ \hline \hline
**Image** & **Satellite** & **Date** & **Polarization** & **Baseline** & **Interval** & **Doppler** \\ \hline \hline
**Slave** & TerraSAR-X & 20160809 & HH & \(-\)65.3631 & \(-\)440 & \(-\)0.03895 \\ Slave & TerraSAR-X & 20160820 & HH & \(-\)184.668 & \(-\)429 & \(-\)0.01011 \\ Slave & TerraSAR-X & 20160911 & HH & \(-\)68.8057 & \(-\)407 & \(-\)0.01479 \\ Slave & TerraSAR-X & 20161025 & HH & \(-\)20.0391 & \(-\)363 & \(-\)0.01932 \\ Slave & TerraSAR-X & 20161116 & HH & \(-\)11.2495 & \(-\)341 & \(-\)0.00188 \\ Slave & TerraSAR-X & 20161230 & HH & \(-\)65.8877 & \(-\)297 & \(-\)0.00235 \\ Slave & TerraSAR-X & 20170121 & HH & 105.2725 & \(-\)275 & 0.007928 \\ Slave & TerraSAR-X & 20170212 & HH & \(-\)15.54 & \(-\)253 & 0.01236 \\ Slave & TerraSAR-X & 20170306 & HH & 68.68008 & \(-\)231 & \(-\)0.00118 \\ Slave & TerraSAR-X & 20170317 & HH & 130.955 & \(-\)220 & \(-\)0.00223 \\ Slave & TerraSAR-X & 20170328 & HH & 53.00705 & \(-\)209 & \(-\)0.00973 \\ Slave & TerraSAR-X & 20170419 & HH & 150.201 & \(-\)187 & \(-\)0.00322 \\ Slave & TerraSAR-X & 20170511 & HH & \(-\)109.816 & \(-\)165 & \(-\)0.01308 \\ Slave & TerraSAR-X & 20170602 & HH & 17.77143 & \(-\)143 & \(-\)0.00789 \\ Slave & TerraSAR-X & 20170624 & HH & 23.69538 & \(-\)121 & \(-\)0.01849 \\ Slave & TanDEM-X & 20171001 & HH & 381.0312 & \(-\)22 & \(-\)0.01324 \\ Master & TerraSAR-X & 20170123 & HH & 0 & 0 & \(-\)0.01263 \\ Slave & TerraSAR-X & 20171141 & HH & \(-\)186.225 & 22 & \(-\)0.00716 \\ Slave & TerraSAR-X & 20171206 & HH & 80.1367 & 44 & \(-\)0.00214 \\ Slave & TanDEM-X & 20171228 & HH & 308.5899 & 66 & \(-\)0.01603 \\ Slave & TanDEM-X & 20180130 & HH & 47.55249 & 99 & \(-\)0.01462 \\ Slave & TanDEM-X & 20180304 & HH & 179.8259 & 132 & \(-\)0.01146 \\ Slave & TerraSAR-X & 20180406 & HH & 160.1782 & 165 & \(-\)0.00857 \\ Slave & TerraSAR-X & 20180428 & HH & \(-\)238.003 & 187 & \(-\)0.0307 \\ Slave & TanDEM-X & 20180520 & HH & 228.5873 & 209 & \(-\)0.02224 \\ Slave & TerraSAR-X & 20180622 & HH & \(-\)10.676 & 242 & \(-\)0.01708 \\ Slave & TerraSAR-X & 20180725 & HH & 8.647546 & 275 & \(-\)0.02195 \\ Slave & TerraSAR-X & 20180827 & HH & \(-\)28.856 & 308 & \(-\)0.00247 \\ Slave & TerraSAR-X & 20180929 & HH & 56.36056 & 341 & 0.001123 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Types of X-band SAR images used in this study. 3. Atmospheric Phase Screen (APS) Correction--Subsequently, atmospheric artifacts, particularly those induced by tropospheric delays, were mitigated using spatial filtering techniques and temporal low-pass filters [21]. 4. Persistent Scatterer Identification--Points with a high temporal amplitude stability and phase coherence were automatically identified and extracted as persistent scatterers [18]. 5.