Based On The Genetic Algorithm Of Magnetotelluric Anisotropic One Dimensional Inversion Study

Soviet scholars Tikhonov and French scholar Garnier had proposed magnetotelluric method in 1950 and 1953, due to the magnetotelluric method is use natural field source, have the advantages of no impact of high-impedance shielded, deep probe, which are widely used in earthquake forecast, crust and upper mantle structure research, energy and resources exploration, hydrology, engineering geophysical and other fields. It is one of the most important methods in the earth’s crust and upper mantle electrical geophysical.Over half a century, magnetotelluric method play a pivotal role in the study of the Earth’s internal electrical structure, but mostly subsurface study is based on the assumption of isotropic. As is known, electrical anisotropy in the Earth’s interior is widespread. There are a lot reasons cause electrical anisotropy(Earth tectonic stress field, tectonic deformation bands, rock fractures, pore water and geological deposits, etc.), basic theory of electrical anisotropy medium systematic study, it is conducive to building approximation of the actual geological conditions geoelectric model, further analysis and interpretation of the Earth’s interior electrical structure foundation. already in the 1960 s, foreign scholars start the research on the one-dimensional electrical anisotropy forward question; now, one-dimensional electrical anisotropy forward research questions already approaching maturity. Two and three-dimensional electrical anisotropy acting forward problem has also made great achievements. until the 1980 s, Chinese scholars study the issue of electrical anisotropy, but the system representation of electrical anisotropy article is rare. Based on the advantages of magnetotelluric method in the study of the electrical structure, this paper will research electrical anisotropic one-dimensional forward and inverse theory.First, from the Maxwell equations, the introduction of the conductivity tensor derived recurrence formula electromagnetic propagation in anisotropic media, analytic derivation of one-dimensional anisotropic electrical problem. Write a one-dimensional forward procedure for electrical anisotropic electrically Model of study lay the foundation for the inversion work; then, based on the characteristics of genetic algorithm to construct the basic frame inversion; the characteristics of magnetotelluric sounding curves and precision and electrical anisotropy inversion of genetic algorithms to improve the object equation by adding regularization term, considering the fitting model and the data on the target equation modified again. Construction of the correctness of the model validation process. Finally, a lot of numerical simulation to analyze the influence of various parameters on the inversion of the inversion results. Substituting the results of one-dimensional anisotropic forward question into two-dimensional isotropic inversion analysis in the presence of anisotropic subsurface, the model results of isotropic inversion is not accurate, illustrating the anisotropic phenomenon is widespread. Finally, test the inversion algorithm performance and effect when added noise to simulation model data in the measured data,. It can be used to analysis and interpretation of magnetotelluric field data in the future.