## 4 Results
### SHAP Dependence Plots  
This study involves the creation of SHAP dependence plots (Figure 9) for all input factors. These plots serve to elucidate the association between factor values and their respective SHAP values. The utilization of dependence plots aims to unveil potential threshold effects by analyzing the variations in SHAP values based on different factor values.  
Geological-tectonic factors reveal that samples with PTF values ranging from 56 to 1847 m yield positive SHAP values in the study area. Notably, sinkhole samples in close proximity to faults exhibit a positive contribution to sinkhole formation. Conversely, locations farther from faults exhibit lower sinkhole formation probability. The SHAP values associated with the LTG factor indicate that only specific lithological formations (Ngi, Ngv, Qh, and some Mof formations) contribute significantly to sinkhole formation.  
In the context of the sole climatic factor, MAP values between 33 and 36 mm yield positive SHAP values, suggesting that the region's minimum and maximum precipitation levels do not significantly contribute to sinkhole formation. Instead, moderate precipitation levels contribute positively to sinkhole susceptibility.  
Environmental-anthropogenic factors also play a crucial role, with WDS values exceeding 0.48 indicating a higher likelihood of sinkhole formation. The PST factor reveals that locations in close proximity to settlements (within 4000 m) generate predominantly positive SHAP values, implying that closer proximity to settlements increases sinkhole susceptibility. Similar trends are observed with the PRD factor, where locations near roads (within 1000 m) exhibit positive SHAP values, indicating an elevated susceptibility to sinkholes. The NDVI factor values above 0.20 yield positive SHAP values, indicating that samples located in areas with healthy vegetation contribute positively to sinkhole formation. SDP values, excluding soil depth class A (very deep soils with a depth exceeding 150 cm), generally contribute positively to sinkhole susceptibility.  
Examining topographic factors, the ELV factor does not exhibit a distinct threshold effect. SHAP values peak between elevations of 1070 and 1080 m, while lower elevations near 1000 m are scattered around zero SHAP values. Regarding the SLP factor, most slope levels exceeding 0.2 generate positive SHAP values, with steeper slopes contributing higher SHAP values. Conversely, flat locations predominantly yield negative SHAP values, indicating low susceptibility to sinkholes. The ASP factor, deemed the least influential, lacks a clear threshold effect. All aspect directions contribute similarly to both positive and negative SHAP values. However, samples with a northeast (NE) direction predominantly yield positive SHAP values. PRC values close to zero primarily result in negative SHAP values, but as PRC values approach +1 (indicating more convex locations), SHAP values increase. Analyzing PDR values, samples within the 0 to 300 m range exhibit a nearly equal distribution of negative and positive SHAP values. Between 300 and 2100 m, a clear positive SHAP value trend emerges, with locations farther from drainage generating negative SHAP values. In essence, locations with distances to drainage between 300 and 2100 m contribute more significantly to sinkhole formation.  
Considering hydrogeological factors, positive SHAP values are observed when DBC exceeds 0.68, DPH is less than \(-\)0.19, DDO is less than \(-\)0.01, and DCH is greater than 0. Additionally, most DDC values above 10.1, DMG values ranging from 0.12 to 1.74, DSU values between 0 and 0.6, and GWD values exceeding 4.71 contribute positively to sinkhole formation. Conversely, most DTI and DPT values scattered around 0 yield more negative SHAP values, although their dependence plots lack a clear threshold effect.