## 4 Establishment and Grading of Evaluation Indicators
### Selection and Correlation Analysis of Evaluation Factors  
The analysis of the conditions, structures, and states of geological disaster formation shows that the occurrence of geological disasters is not determined by a single factor  
Figure 4: Detailed slope unit division map of Huangshi Town. Figure 3: Preliminary slope unit division map [30; 31]. Therefore, the assessment of geological disasters must comprehensively consider multiple influencing factors. Scientifically, comprehensively, and reasonably selecting evaluation indicators forms the foundation for disaster-susceptibility assessment [32]. Based on the Technical Requirements for Geological Hazard Risk Survey and Evaluation in Towns (Streets) of Guangdong Province (1:10,000) (Trial) and the actual geological environment and disaster types of Huangshi Town [33]. This study selected the evaluation factors as follows. Topographic factors such as slope, aspect, slope shape, and terrain undulation were extracted from Digital Elevation Model (DEM) data; engineering geological rock groups and cover layer thickness were obtained based on geological survey data; vegetation coverage was calculated through remote sensing image inversion; while land use type, slope structure, and cut-slope height were primarily determined through field investigation and surveying [34]. The influence mechanisms of each factor on slope stability are as follows: greater slope steepness increases the tangential component of gravity, significantly raising instability risk; aspect affects solar radiation and weathering, indirectly altering the physical and mechanical properties of rock and soil; different slope shapes cause stress variations--convex slopes are prone to tensile stress at the top, and concave slopes to shear stress at the base--both weakening stability; greater terrain undulation indicates stronger tectonic activity and erosion, leading to higher rock fragmentation and instability risk. In terms of geological background, thicker cover layers and weak lithologies or well-developed structural planes reduce shear strength and increase deformation and failure risks. Surface coverage conditions regulate hydrological processes and erosion resistance; higher vegetation coverage strengthens soil and reduces water content, lowering disaster risk, while human activities, reflected by different land use types, further destabilize slopes. Regarding hazard characteristics, weak structural planes within slopes tend to form potential sliding surfaces, significantly undermining stability; increased cut-slope height weakens toe support, causing stress imbalance, and is a key factor in the frequent geological disasters in Huangshi Town [35]. To perform the correlation analysis of the geological disaster-susceptibility evaluation factors for Huangshi Town, the Pearson correlation coefficient matrix between the susceptibility evaluation factors is obtained (Table 1). According to the correlation coefficient classification table, a coefficient smaller than 0.5 indicates a low correlation between factors, meaning no collinearity exists, and the factors can be used as predictive variables. The correlation coeffici