Characterization of acceptable risk for debris flows in China: Comparison in debris-flow prone areas and nonprone areas

People's perception of debris-flow risk may be different in debris-flow prone and nonprone areas. Investigation of population risk consensus in different regions may provide a high-quality technical analysis for the acceptable risk criteria of debris-flow disasters. For this study, five indicators (disaster-affected toll, death toll, death rate, personal direct economic loss, and total direct economic loss) were designed to determine the acceptable risk level of debris-flow disasters for the public, and the demographic characteristics of the public affecting the acceptable risk of debris-flow disasters were identified using five factors (age, sex, educational level, occupation, and income). Questionnaire surveys were conducted in debris-flow prone and nonprone areas, respectively. A total of 823 valid samples were obtained, among them, 459 questionnaires were collected in debris-flow prone areas, and 364 questionnaires were collected in debris-flow nonprone areas. After statistical and comparative analyses, the results demonstrate that the acceptable criteria of disaster-affected toll was 100 persons, death toll was 1 person, death rate was 5 × 10−7/year, personal direct economic loss was 1000 CNY, and total direct economic loss was 1 × 105 CNY. Age and sex exhibited almost the same features for the acceptable risk levels of debris-flow disasters, whereas educational level, occupation, and income displayed discrepancies in both study areas, which resulted from imbalanced economic development, discrepant risk perception, and differing personal wealth.