Abstract:
Based on elaboration of the concept and principle of WoE, Lanzhou urban area, which is highly prone to slides and falls in the Loess Plateau of Northwest China, is taken as example to detail technical process of regional geological hazards susceptibility assessment based on the WoE. GIS tools are used to carry out evaluation index selection and correlation analysis, weight and posterior probability analysis of evidence factors, assessment model verification, and susceptibility degree classification and assessment. The analysis results show that there is no correlation or weak correlation between the factors affecting geological hazards such as slope, slope direction, stratum lithology, faults, waterfalls, green irrigation and land use type, which meets the requirements of mutual independence. AUC (Area Under Curve) of the ROC curve (Receiver Operating Characteristic Curve) of the model is 0.85, which means high prediction accuracy. Theoretical analysis and empirical application have demonstrated that, in comparison with other statistical methods, the WoE takes into account both probability of the presence and absence of geological hazard within the evaluation factors. Thereby, it prevents distortion caused by overestimation of weights when geological hazards are absence. The result of the WoE is the absolute probability of the occurrence of geological hazards, which can serve as a basis for comparing the susceptibility of geological hazards from different areas.