Research For Non-linear Joint Inversion Theory Of Electric And Seismic

With the increasing of requirements of the shallow geophysical interpretationaccuracy, coupled with the single method inversion of multiple solutions existence, oftenusing a geophysical method is difficult to meet the requirements of exploration, and wemust use two or more than two kinds of integrated geophysical methods. Doing eachmethod advantages, enriching information of geophysical anomaly and bring about the jointinversion of integrated geophysical anomaly, which can effectively make the multiplicity tolimit or avoid, and improve the.precision of data interpretation. The so-called jointinversion is an important quantitative interpretation method of integrated geophysicalprospecting, and joint inversion of the present research mostly uses the linear localoptimization method. This not only seriously depend on the selection of initial model, andis easy to fall into local optimal solution, especially for the local anomaly caused byunderground thin layer it is more difficult to achieve satisfactory inversion fitting effect.Therefore, carrying on research of nonlinear joint inversion of integrated geophysicalanomaly has become the modern research topic in current research of geophysicalinversion.In recent years, DC resistivity sounding method and Rayleigh method play animportant role in the shallow geophysical sounding in the field because of the relativelymature technology. In view of the single method inversion of multiple solutions existence,we often use the two method in the form of integrated geophysical prospecting method, butat present its anomaly inversion were still in their individually, and often limited to thelinear or linearized inversion theory, so it is necessary to carry on research of nonlinearjoint inversion. In this regard, this paper applies the differential evolution algorithm to thejoint inversion of DC resistivity sounding method and Rayleigh wave method for the firsttime, uses difference vector instruction within group and the exchange of informationbetween individuals in group to carry on heuristic global search were not depended ongradient information in the differential evolution. does algorithm advantages of easy to use,powerful global search ability and strong robustness and sets up a complete set of shallowelectric and seismic nonlinear joint inversion theory.This paper starts from the theoretical analysis of DC resistivity sounding method andRayleigh wave exploration. First of all, We analyze the principle and forward theory of DCresistivity sounding method and Rayleigh wave method by the numbers. After that, on thebasis of deeply studying of differential evolution algorithm and its characteristics, the mainproperty parameters and other related content, we step up the theoretical model ofone-dimensional nonlinear joint inversion of DC resistivity sounding method and Rayleighwave method. Through the analysis of test, we select a suitable set of inversion parameters,and taking advantage of Matlab system platform program joint inversion procedure of DCresistivity sounding method and Rayleigh wave method based on differential evolution algorithm. After the theoretical model calculation, it is show that the joint inversion modelhas strong stability and greater popularization ability. Finally, joint inversion program isused in joint inversion of DC resistivity sounding and Rayleigh wave data of typical holehas been known. Further it is confirmed that the fitting inversion accuracy compared withthe existing interpretation method is obviously improved, and the consumption of machineoperation also significantly decreases.Research results show that: joint inversion method of electrical sounding and Rayleighwave based on differential evolution algorithm can effectively avoid or limit themultiplicity problem from single method, and has fast convergence speed, high fittingprecision and strong ability of generalization. The result of this research has opened up anew field of nonlinear theory in geophysical joint inversion, and the research results canfurther be used into joint inversion of other geophysical methods and2D or3D geophysicaljoint inversion theory.