Research On The Correlation Of Reservoir Geological Environment And Induced Earthquake Based On Copula Functions

As an important water conservancy project infrastructure,reservoir has become an indispensable strong pillar in the process of economic and social development of every country.Its flood control and drought relief,hydropower generation,river shipping,agricultural irrigation,ecological protection,tourism and tourism and a series of powerful functions have brought countless wealth and convenience to people.However,everything has its disadvantages.The reservoir blocks a large amount of water due to the impoundment,which will greatly change the stress environment of the reservoir area and its surrounding areas,and a series of changes may cause the reservoir earthquake.Reservoir earthquake,which is not easy to be predicted and destructive once happened,has attracted great attention of all countries and regions.In view of the fact that most of the researches on the geological environment conditions of reservoir induced earthquakes at home and abroad are qualitative,and the quantitative research is far from enough,Copula function is introduced to analyze the correlation between the geological environment of reservoir and induced earthquakes,in order to quantitatively discuss the correlation between each geological environment condition factor of reservoir and earthquake magnitude on the basis of qualitative analysis Relationship.Firstly,based on the review of relevant literature and the analysis of the research progress at home and abroad,the paper determines the research ideas and research contents;Secondly,the basis of principle of coupla function and geological environment of reservoir induced earthquake is analyzed.The definition,properties,common types,methods of correlation measurement,types of induced earthquake factors,classification and quantification methods and magnitude characteristics of Copula function are understood;Next,based on Copula function,the correlation analysis method of reservoir induced earthquake factor and magnitude is proposed.The edge distribution of induced earthquake factor and magnitude is calculated by kernel estimation,and Gumbel,Clayton,Frank Copula and M-Copula are used to construct the correlation model,and then the parameters in copula are estimated by the maximum likelihood estimation.Then,the Q-Q graph method,K-S test method and the minimum distance method are used to test and optimize the fitting degree of several Copula functions.The best copula function can be selected by calculating its tail The correlation coefficient,joint distribution and conditional probability can be used to quantitatively analyze the correlation between induced earthquake factors and magnitude;Finally,taking the Yangtze Three Gorges Reservoir as an example,four representative geological environment factors of reservoir induced earthquake,such as fracture,karst,crevice and reservoir load,are selected.Using the above correlation analysis method,the copula functions of four factors and magnitude is constructed respectively,and the correlation between them is quantitatively analyzed by copula function.The results show that the copula function can be used to quantitatively reveal the correlation of reservoir earthquakes of different magnitudes induced by different reservoir geological environments in different states,which not only has important theoretical significance for the study of the mechanism of reservoir induced earthquakes,but also provides important reference value for the risk prediction of reservoir induced earthquakes.