Risk Assessment Of The Geological Disaster Chain Induced By The Eruption Of Changbai Mountain Volcano

The impact of powerful natural hazards such as volcanoes or earthquakes and their induced secondary disasters on ecosystems and the environment were attracted more and more global attention,experts and scholars from different fields have developed a strong interest in the formation process of secondary disasters caused by natural hazards and conducted relevant studies.The phenomenon of the occurrence of another or more disasters induced by one kind of disaster is called disaster chain.At present,there are many researches about the definition,classification method and formation mechanism of disaster chain,however,the quantitative risk assessment of disaster chains has not yet formed a unified form.This is because of the complex interactions between the causal disaster events in the disaster chain system,which made the study of risk assessment more difficult.But the development of probabilistic inference models such as Bayesian Networks provides an opportunity to research these complex correlations.Firstly,based on the cases of secondary disaster chains induced by large-scale natural hazards in history,the disaster chains types induced by volcanic eruptions and their formation mechanism were analyzed,and according to the geological structure characteristics of Changbai Mountain region,the possible types of disaster chain induced by the Changbai Mountain volcano eruption were summarized,the research object of this study was confirmed to be the volcano-earthquake-collapse-landslidedebris flow disaster chains.Secondly,on the basics of theoretical principles of Bayesian Network model,the Bayesian Network model of the geological disaster chain induced by volcanic eruption was constructed,which includes 9 impact factors such as earthquake intensity,elevation,slope,slope aspect,lithology,distance from rivers,distance from faults,land use and annual average rainfall.Finally,according to the risk formation theory of natural hazards,the risk assessment model of geological disaster chain was constructed from two aspects: hazard and vulnerability.The following conclusions can be drawn from the above research:(1)The geological disasters chain types induced by Changbai Mountain volcano eruption include: volcano earthquakes-collapse-landslide-debris flow disaster chain;volcano eruption(associated earthquake)-Tianchi dam(flood)-volcano debris flowdisaster chain;volcano(associated earthquake)-Tianchi dam(flood)-debris flowcollapse and landslide disaster chain.(2)In the Changbai Mountain regions,zones of high and medium risk of the volcano earthquake-collapse-landslide-debris flow disaster chain were predominantly located within a 10-km radius,while the north and south of the study area mainly contain very low-to-low risk values.(3)The ROC curve method verified the evaluation results of the disaster chain risk assessment model,and the results showed that the AUC value of the area under the ROC curve is 0.8012,which indicated that the evaluation effect of the model is good.The results of this study can provide a good decision support for prediction and early warning,disaster rescue,reduction and broken of geological disaster chains in Changbai Mountain regions,and provide the basis to risk prevention measures for local conditions.