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To study the susceptibility of debris flow in Kangding City, the study area was divided into 421 watershed units. Spatial analysis tools in ArcGIS software and SPSS software were used to analyze the internal superposition of evaluation indicators and the correlation between evaluation indicators and debris flows disasters. By screening out the evaluation factors with a high degree of overlap and poor correlation, eight evaluation factors were selected for debris flow susceptibility assessment. These included watershed unit area, melton rate, form factor ratio, collapse and landslides density of catchment, average fractional vegetation cover of catchment, road density of catchment, average stream power index of catchment, and average rainfall during the multi-year flood season. The susceptibility of debris flow was quantitatively evaluated by combining the information value model and the entropy method. The weights of the evaluation indicators were quantitatively determined by the entropy method, and the evaluation factor weighted information quantity value was calculated. Based on this, the debris flow susceptibility in Kangding City was divided into four grades: extremely high, high, medium and low. The results of debris flow susceptibility assessment were tested using the frequency ratio model and the Receiver-Operating Characteristic (ROC) curve, with an AUC curve of 0.842, indicating high accuracy of the evaluation model. more...

To study the susceptibility of debris flow in Kangding City, the study area was divided into 421 watershed units. Spatial analysis tools in ArcGIS software and SPSS software were used to analyze the internal superposition of evaluation indicators and the correlation between evaluation indicators and debris flows disasters. By screening out the evaluation factors with a high degree of overlap and poor correlation, eight evaluation factors were selected for debris flow susceptibility assessment. These included watershed unit area, melton rate, form factor ratio, collapse and landslides density of catchment, average fractional vegetation cover of catchment, road density of catchment, average stream power index of catchment, and average rainfall during the multi-year flood season. The susceptibility of debris flow was quantitatively evaluated by combining the information value model and the entropy method. The weights of the evaluation indicators were quantitatively determined by the entropy method, and the evaluation factor weighted information quantity value was calculated. Based on this, the debris flow susceptibility in Kangding City was divided into four grades: extremely high, high, medium and low. The results of debris flow susceptibility assessment were tested using the frequency ratio model and the Receiver-Operating Characteristic (ROC) curve, with an AUC curve of 0.842, indicating high accuracy of the evaluation model. [ABSTRACT FROM AUTHOR] more...

The Bailong river basin is a densely distributed area of geological disasters such as debris flow. In August 2020, due to the stimulation of heavy rainfall, a large-scale group debris flow disaster occurred in Wudu section of Bailong river basin, causing serious losses. This paper takes the Wudu section (Lianghekou Township, Dangchang County to Jugan Town, Wudu District) of Longnan City in Gansu Province as the research area. Through field investigation, we selected the area of drainage basin, shape coefficient of basin, average slope, density of gully, reference value of material source (HI), lithology, distance between basin center and active fault, one hour maximum rainfall and vegetation coverage as debris flow hazard assessment factors. Taking single gully and small watershed units of debris flow as evaluation units, the regional debris flow hazard assessment is carried out by using ArcGIS software based on the theory of disaster entropy. The results show that most of the debris flows in the study area belong to medium and high hazard debris flow gullies. Some of the most heavily weighted disaster-causing factors like the weight of lithology, source reference value (HI), distance from fault, vegetation coverage and average slope are consistent with the actual investigation results. Moreover, the evaluation results of small watershed units are more consistent with the development of debris flow in the study area. more...

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