Evaluation index selection of debris flow based on entropy value theory

Abstract

Aiming at solving the deficiencies of index weight determination in evaluating risk of geological disaster, the theory of minimum entropy analysis was used to form nonlinear independent components. The index optimization and weight determination were done based on their contributions to debris flow. The index weights were evaluated in the classic debris flow risk evaluation model. The evaluation results were compared with the calculated results. Analysis result shows that the main optimal indexes are the maximum rushed amount for a debris flow, frequency, basin area, main gully length, main gully bed tortuosity coefficient, vegetation coverage, the reserve of loose solid material, basin cutting density and sediment supply length ratio. The corresponding weight values of these indexes are 0.2353, 0.2353, 0.0791, 0.0791, 0.0791, 0.0791, 0.0730, 0.0730 and 0.0730 respectively. The numbers of extreme, heavy, moderate and slight debris flows are 3, 3, 6 and 0 respectively. The calculated results are consistent with the real situation and development trend of studied debris flow area. It proves the reasonability of minimum entropy analysis theory applied in geological disaster risk evaluation.