Evaluation and Driving Force Analysis of Geological Disaster Risk in Mountainous Counties of Northern Guangdong Based on Multi-source Model
The uncertainties of time,space and scale of geological disasters bring great difficulties to disasters prevention and mitiga-tion.The risk assessment of geological disasters is very important to reduce the uncertainty of geological disasters and regional disaster prevention and reduction.Therefore,it is very necessary to evaluate the risk of regional geological disasters.This study takes Wengyuan County in the mountain area of northern Guangdong as an example,13 evaluation indicators of natural environment,location distance and human activities which are closely related to geological disasters are selected,and are verified for the correlation of evalua-tion indicators based on Pearson correlation coefficient.Firstly,the information value of each evaluation index classification interval is obtained based on the information quantity model,and then the random forest model is used to determine the weight of each evaluation index to weight the information quantity model to get the geological disasters prone result of I-RF model.Finally,the geographical de-tector is used to detect the factors of the results of the Information-Random forest(I-RF)model,and the influence degree of each eval-uation factor on the risk of geological disasters is quantitatively analyzed.The results show that:(1)The ROC curve verifies that the AUC value reaches 0.890,indicating that the I-RF model can better analyze and depict the risk pattern of geological disasters in the study area.(2)The area of high and high prone areas in the study area accounts for 49.85％,which is mainly distributed in valley plains and hilly areas where human activities are strong and ecologically sensitive and fragile,while middle and low prone areas account for 50.15％,mainly distributed in the low mountain hilly areas with little human disturbance,high vegetation cover,relatively low rainfall and rainfall erosion force.(3)From the county center,Longxian Town,which has good economic development,frequent con-struction activities and high development intensity,it is more likely to suffer from geological disasters,while for Tielong Town,which pays attention to ecological protection and relatively less intensity of human activities,it is less prone to geological disasters.(4)From the point of view of the driving factors of geological disasters,the factor detection results show that elevation,population footprint and geological rock groups are the common inducing factors of collapse,landslide and debris flow in the study area.The interactive detec-tion results show that elevation is the primary driving factor for the occurrence of geological disasters in the study area.Collapse and landslide are mainly driven by the interaction between elevation and the distance from the river,topographic relief and rainstorm rain-fall,while debris flow is mainly driven by the interaction between elevation and the evaluation indicators of topography,geological structure,hydrometeorology and human activities.On the whole,the risk degree of geological disasters in the whole county is on the high side.In the process of prevention and control of geological disasters in the future,different policies need to be implemented for different geological disaster risk areas and types of geological disasters.
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