Geological hazard susceptibility evaluation in Wenchuan area based on three models of multivariate instability index analysis

A derived model of multivariate instability index analysis method was proposed to evaluate the susceptibility of geological disasters in Wenchuan County. Based on the data of potential geological hazards in Wenchuan County released by Sichuan Provincial Department of Natural Resources, six influencing factors including slope, aspect, stratum lithology, distance from fault, vegetation coverage and distance from water system are involved. Three different methods of multivariate instability index analysis, namely power multiplication, linear accumulation and power accumulation, are used to obtain the geological disaster susceptibility zoning map of the study area Receiver Operating Characteristic (ROC) curve verifies the evaluation performance of various models. The results show that: (1) for this case, the power multiplication model has the highest accuracy compared with the other two models; (2) the percentages of area with different susceptibility levels, i.e. very high, high, moderate, low, and very low, are 19.3%, 24.6%, 19.2%, 19.3%, 17.6% respectively, moreover, the higher level of susceptibility, the closer to the fault zones. This research provides theoretical and technical reference for the prevention and mitigation of regional geological disasters.