Dynamic Risk Assessment Of Debris Flow In Mountainous Areas Induced By Extreme Rainfall

In recent years,the frequency and scale of disasters related to extreme climate events have been increased.The main cause of geological disasters in Jilin Province is caused by natural precipitation,and extreme precipitation is one of the important factors leading to such disasters.Taking Tonghua County,located in the southeastern mountainous area of Jilin Province,as the research area,based on the formation mechanism of natural disaster risk,combined with multi-source data and remote sensing information in the study area,the breeding mechanism of geological hazards and spatial-temporal distribution characteristics are studied,and a comprehensive database of regional geological hazard risk is established,and the dynamic evaluation index and evaluation model of regional debris flow geological hazard risk are constructed.Combining rainfall dynamic data with the calculation of optimization model of socio-economic interannual change data(static to dynamic),the dynamic risk assessment of regional debris flow geological hazards is completed,which provided scientific basis and reference suggestions for debris flow disaster management in this area.The main research results are as follows:(1)The debris flow disasters in Tonghua County mainly occurs in the rainy season(June-September).The monthly average rainfall in August is the largest.The debris flow disasters mainly occurs in Yingebu Town,Quidamao Town,Gangou Township and Sipeng Township in space;The main factors affecting the geological environment of debris flow disasters in the study area are lithology,geological structure,topography,meteorology,hydrology and vegetation conditions.The main disaster-bearing bodies are population and economic property;the main disaster-causing factors of debris flow in the study area are precipitation..(2)Based on the risk assessment of debris flow hazards in the study area,the change trend of risk factors of debris flow hazards in the study area is analyzed.The risk distribution of debris flow hazards converged from the internal uniform distribution to Gangou Town,Kuaidamao Town,Yingebu Town,Jindou Town and Daquanyuan Town and Jiangdianzi Town in the south;The exposure of debris flow hazards migrates from the study area.Sankeyushu Town and Daquanyuan Town in Southwest China moved to Gangou Town and Xinglin Town as well as Jiangdianzi Town in Southeast China;The vulnerability of debris flow hazards migrated from Daquanyuan Town in the southwest to Gangou Town and Xinglin Town in the middle and north of the study area;The ability of disaster prevention and mitigation of debris flow in the region is lower in most towns in the central part of the early study area.With the economic development,Kuaidamao Town,Jindou Town and Gangou Town in the central area of Tonghua County gradually improved the disaster prevention and mitigation of debris flow.Disaster capacity;In the dynamic assessment of regional debris flow disaster risk,high-risk areas migrated from Daquanyuan Town in the southwest and Daan Town in the northeast,Qidaogou Town in the flying region to Kuaidamao Town,Jiangdianzi Town and Donglai Town along the urban area.(3)The risk management countermeasures of debris flow disaster based on the results of risk zoning are analyzed,and a scientific and perfect disaster risk management process(based on the whole process and the theory of natural disaster risk formation)is proposed.It includes three disaster risk management processes(pre-disaster,middisaster and post-disaster)and four disaster integration concepts(hazard,exposure,vulnerability and disaster prevention and mitigation capabilities)to improve disaster risk emergency response methods,strengthen information sharing and management,and popularize risk management awareness.