Assessment of relative importance of debris flow disaster risk affecting factors based on meta-analysis – cases study of northwest and southwest China

Abstract. Debris flow is a type of special torrent containing numerous solid materials. It is characterized by sudden outbreak, short duration, and strong destructive force. The occurrence of debris flow is often affected by hydrogeological and geological conditions, including basin area, main ditch length, relative height difference, slope, bed bending coefficient, daily maximum rainfall and so on. With many types of factors affecting debris flow, no reliable basis for selecting factors to evaluate debris flow risk has been established. Therefore, to study the factors affecting debris flow, exploring a reliable method for assessing the relative importance of such factors is an important endeavor in debris flow prevention and control work. In this research, debris flow risk assessment was combined with meta-analysis to analyze quantitatively the relative importance of risk factors of debris flow in northwest and southwest China. Results show that debris flow in northwest China is mainly affected by topography and geological structure. Rainfall plays an important role in stimulating debris flow in this area. For debris flow in southwest China, topography, geological structure, and rainfall conditions all have considerable influence. Meta-analysis can provide a basis for the selection of risk factors of debris flow and has certain reliability.