The Finite Element Modeling Of Magnetotelluirc In Two-dimensional Anisotropic Media

After over half a century of research, the magnetotelluric(MT) method has been widely applied. And the magnetotelluric(MT) method theoretical study on Electric isotropic, has changed from the initial simple 1-Dimension forward modeling and inversion to today's arbitrary study of Three-Dimensional model, at the same time 2-Dimension forward and inversion has been widely used in practical production, so much as the three dimensional study has been carry out in individual regions. but the more we learn about the earth, the more scholars have noticed that the widespread electrically anisotropic media within the earth can not be ignore during the processing and interpretation of MT data. Therefore, in recent years, the study of MT anisotropy forward and inversion became very active, and also has been get the substantial progress in domestic and foreign.Based on the above, in this paper the research has been targeted underlying the condition of electrical anisotropy to studding MT 2D forward modeling. The goal is to accomplish the Calculation of magnetotelluric two dimensional anisotropy inversion with the method of software program, and the results will be analyzed and studied to find the features and rules.First of all, it starts from the Maxwell's equations which has the characteristics of magnetotelluric field, introducing tensor electrical resistivity, and the magnetotelluric field system of partial differential equations of the second order are derived in the case of electrical anisotropy. and then, through the C++ programming and takeing advantage of the finite element modeling technology, to find solution of the magnetotelluric field system of partial differential equations of the second order. on this basis common models are selected to analyses and summarize the two-dimensional response of anisotropic magnetotelluric field. It is found that the data in the TE model is more close to the isotropic response results in an anisotropic model in the X direction, as well as the data in TM mode is more close to the isotropic response results in an anisotropic model in the Y direction. At last, selected the different MT forward modeling data of anisortropy to carry out magnetotelluric two dimensional isotropic inversion, these studies can provide some basis in the selection of magnetotelluric inversion data during the actual production. So in actual exploration, when the curve of data under the two models is inconsistent,if our focus is mainly on underground resistivity in the X direction or in reducing the influence of static displacement,under these circumstances the data in the TE model can be used to inversion,In others, Whether it is high resistance or low resistance the TM data all have higher sensitivity. Inversion with TM data is the basic consideration. And the joint inversion of TE and TM data must be avoided...