## 5 Discussion  
### IVCI Model Verification and Evaluation  
To assess the accuracy of the model after integrating InSAR, this study selected three significant correction areas for the validation and evaluation of the IVCI model, using both SBAS-InSAR and optical remote sensing images. The Y-1 region is situated at elevations ranging from 1070 to 1170 m, with most slopes falling within the 20\({}^{\circ}\) to 25\({}^{\circ}\) range. The character of the terrain in this region is more susceptible to landslide hazards (Figure 11). According to the interpretation of various optical images from different time periods, a shallow surface landslide developed near the toe of the slope close to the road in February 2011. In April 2017, eight shallow landslides occurred within this area, characterized by elongated shapes, with most of the landslide mass being soil (Figure 12). The optical remote sensing images indicated that the slope in this area is relatively unstable and prone to minor landslides. The SBAS-InSAR results (Figure 13) indicate that the subsidence rate within the Y-1 area is mostly greater than 10 mm/y, suggesting ongoing slope subsidence deformation. To understand the variation of subsidence within the slope, representative point P-1 (E 176.230548\({}^{\circ}\), N 15.189933\({}^{\circ}\)) was selected within Y-1, based on the interpretation results from optical remote sensing. Based on the settlement measurements of P-1 (Figure 13), the point remains in a fluctuating state, experiencing significant displacements after the rainy season each year, with a maximum displacement of 40 mm. Although some rebound phenomena are observed, the overall condition indicates settling. Figure 11: Comparison of landslide susceptibility for Y-1 under the (**a**) IV-CatBoost model and (**b**) IVCI model. Figure 12: Y-1 optical remote sensing interpretation. (**1–9**), delineated by the red lines, are all classified as shallow surface landslides. The images (**a,b**) are both derived from Maxar satellite data. The Y-2 area is located at elevations ranging from 860 to 960 m, with most slopes falling between 25\({}^{\circ}\) and 30\({}^{\circ}\), making the terrain relatively steep (Figure 14). The roads in the area are more susceptible to the impact of landslides and other disasters. According to the interpretation of various optical images from different time periods, seven shallow landslides occurred near the sides of the roads, with some containing small rock fragments, in May 2012 (Figure 15). In October 2015, another shallow surface landslide occurred within the scope of landslide area (5). The interpretation results indicate that the slopes on both sides of the roads in this area are prone to small-scale shallow landslides under various disturbances. The SBAS-InSAR results show (Figure 16) that the subsidence rate in the Y-2 area is mostly greater than 10 mm/y. Based on the settlement data at point P-2 (E 119.340640\({}^{\circ}\), N 27.822157\({}^{\circ}\)) (Figure 16), it is clear that this point experiences fluctuations akin to P-1. Settlement is closely tied to the rainy season, with a maximum displacement of 60 mm. Although some rebound is observed, the overall trend is still downward. The Y-3 area is situated at elevations ranging from 1100 to 1160 m, with the majority of slopes having gradients between 15\({}^{\circ}\) and 20\({}^{\circ}\) (Figure 17). While there is a significant difference in altitude, the slopes exhibit relatively minor variations in gradient. According to the interpretation of various optical images from different time periods, three shallow surface landslides were observed on the slopes in April 2013. In March 2016, another shallow surface landslide developed. The (5) and (6) slopes in this area, characterized by bare rock surfaces in different seasons, are susceptible to rockfall and similar disasters (Figure 18). These slopes are in an overall unstable situation. Figure 14: Comparison of landslide susceptibility for Y-2 under the (**a**) IV-CatBoost model and (**b**) IVCI model.