Abstract
Debris flow is a type of special torrent containing numerous solid materials. With many types of factors affecting debris flow, there is no reliable basis for the selection of risk factors for debris flow risk assessment. Therefore, to study the factors affecting debris flow, exploring a reliable method for assessing the relative importance of these factors is a significant 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. The final relative importance of each factor in northwest China is as follows, maximum relative height difference > slope of main channel > maximum daily precipitation > ratio of longitudinal slope > drainage area > length of main channel. In addition, in southwest China, maximum relative height difference > maximum daily precipitation > slope of main channel > ratio of longitudinal slope > length of main channel > drainage area. The meta-analysis results were accurate, which can provide a reliable basis for the selection of debris flow risk factors in debris flow risk assessment. Furthermore, it provides strong support for the application of meta-analysis in risk assessment of other geological hazards.
Highlights
Debris flow is a type of sudden natural disaster in mountainous areas and a complicated natural geographical process of landmarks
With debris flow in China taken as an example, this study collected and collated a large number of data relating to debris flow
This study provides a reliable basis for the selection of debris flow factors
Summary
Debris flow is a type of sudden natural disaster in mountainous areas and a complicated natural geographical process of landmarks. To analyze the relationship between environmental factors and landslides and debris flow disasters nationwide, Zhang [14] selected six factors, including elevation, elevation difference, slope, slope direction, vegetation type, and vegetation coverage. Based on the “2 major factors plus 14 minor factors” proposed by Liu Xilin, Chen [15] selected the maximum outflow quantity and frequency of debris flow as major factors through a preliminary screening of scatter diagram and the continued screening of rank correlation coefficient. Zhu Liang introduced a clustering validity index to determine the clustering number, and the fuzzy C-means algorithm and factor analysis method were combined to classify 21 debris flow catchments in northeast China, the weight order of each of the factors selected were basin area > main channel length = maximum elevation difference > drainage density > average slope angle [16]. According to the results of previous studies, the selection of debris flow impact factors can be generally divided into single-channel study and regional study, and the selection of impact factors has its emphasis depending on the research environment
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