Evaluation of debris flow risk based on independent information data fluctuation weighting method

In view of the deficiencies of grey relational analysis used in current ways for selecting secondary risk factors when evaluating debris flow risk, multiple correlation coefficient is used to select secondary risk factors. Thus, multiple factor system consisted of primary risk factors and secondary risk factors for evaluating debris flow risk is established. On this basis, a new independent information data fluctuation weighting method is used to calculate the weights of secondary risk factors. With the new weighting method, the relations among the primary risk factors and secondary risk factors can be decreased and the contribution of secondary risk factors to debris flow risk can be expressed. With the selected factors and weights, the calculation formula of debris flow risk is proposed. Then the new formula is taken to calculate the debris flow risk of 12 debris flow gullies in Dongchuan city. The results coincide with the added status of secondary factors which improves the rationality of the method.