## 3 Study Area and Data
### Landslide Predisposing Factors
#### 3.3.1 Geomorphological Factors  
Elevation (Figure 5a), aspect (Figure 5b), slope (Figure 5c), and topographic relief (Figure 5d) are typical geomorphological factors that play significant roles in the formation of landslides [43]. Elevation determines the climatic characteristics and hydrodynamic conditions of a certain area [46]. Climate change affects the distribution of species and the characteristics of human activities [47]. Thus, it can cause changes in surface vegetation, weathering, and the degree of human activity, which deeply affect the development of landslides. Moreover, aspect is closely related to soil moisture and the lighting conditions, thereby influencing slope stability [14]. Due to the influence of the aspect factor on solar radiation and wind conditions, the water action conditions, vegetation coverage, and weathering of these slope units show significant differences. As shown in Table 3, aspect is generally classified into nine categories, with a \(-1\) value representing flat land [22]. Moreover, the slope can alter the stress distribution and strain accumulation in the stress field of the slope body [5]. Within a certain range of slope values, the stability of the slope body usually decreases as the slope increases. Topographic relief reflects the magnitude  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Predisposing Factor** & **Value** & **FR** & **LAIFR** & **DFR** \\ \hline  & 0–0.12 & 0.317 & 0.510 & 0.162 \\  & 0.12–0.28 & 1.174 & 0.350 & 0.411 \\ Fault density & 0.28–0.40 & 1.523 & 0.535 & 0.814 \\ (km/km\({}^{2}\)) & 0.40–0.50 & 1.406 & 0.545 & 0.767 \\ (PF\({}_{6}\)) & 0.50–0.62 & 3.370 & 0.493 & 1.660 \\  & 0.62–0.78 & 2.167 & 0.543 & 1.176 \\  & 0.78–0.98 & 0.696 & 0.333 & 0.232 \\  & 0.98–1.22 & 1.702 & 0.800 & 1.362 \\ \hline PGA (g) & 0.20 & 0.641 & 0.684 & 0.439 \\ (PF\({}_{7}\)) & 0.30 & 1.122 & 0.466 & 0.522 \\  & 0.40 & 0.072 & 0.500 & 0.036 \\ \hline  & 0–0.15 & 0.082 & 0.500 & 0.041 \\  & 0.15–0.36 & 1.097 & 0.500 & 0.549 \\ River density & 0.36–0.60 & 1.619 & 0.496 & 0.803 \\ (km/km\({}^{2}\)) & 0.60–0.90 & 2.639 & 0.430 & 1.134 \\ (PF\({}_{8}\)) & 0.90–1.27 & 0.414 & 0.583 & 0.241 \\  & 1.27–1.70 & 0.151 & 0.667 & 0.101 \\  & 1.70–2.36 & 0.000 & 0.000 & 0.000 \\  & 2.36–3.35 & 0.000 & 0.000 & 0.000 \\ \hline  & \(-1.00\)—0.13 & 0.000 & 0.000 & 0.000 \\  & \(-0.13\)–0.06 & 0.393 & 0.857 & 0.337 \\  & 0.06–0.17 & 1.936 & 0.426 & 0.824 \\ NDVI & 0.17–0.27 & 0.878 & 0.563 & 0.494 \\ (PF\({}_{9}\)) & 0.27–0.40 & 0.288 & 0.500 & 0.144 \\  & 0.40–0.56 & 0.637 & 0.588 & 0.375 \\  & 0.56–0.71 & 0.046 & 1.000 & 0.046 \\  & 0.71–1.00 & 0.000 & 0.000 & 0.000 \\ \hline  & 50–71 & 0.437 & 0.588 & 0.257 \\  & 71–89 & 2.712 & 0.422 & 1.143 \\ Annual precipitation (mm) & 89–103 & 0.419 & 0.651 & 0.273 \\
103–124 & 0.213 & 0.800 & 0.170 \\
124–151 & 0.051 & 1.000 & 0.051 \\
151–203 & 0.000 & 0.000 & 0.000 \\
203–287 & 0.000 & 0.000 & 0.000 \\  & 287–420 & 0.000 & 0.000 & 0.000 \\ \hline \end{tabular}
\end{table}
Table 3: _Cont._of the elevation variation within a certain area. With higher topographic relief, the slope generally tends to accumulate more gravitational potential energy and exhibits stronger sliding forces. In addition, excessive topographic relief can amplify the intensity of hydrodynamic actions such as operand flow and groundwater seepage, which are unfavorable for slope stability [48].