一种反演不均匀介质大地电磁测深资料的方法

AN APPROACH TO THE INVERSION OF THE MAGNETOTELLURIC DATA OF THE INHOMOGENEOUS MEDIUM

通过反演受近地表不均匀介质影响的大地电磁测深资料的新方法,可获得较准确的一维地电断面参数、不均匀体埋藏深度及其电性特征。本方法计算速度快,单测ρ_(xy),ρ_(yx)可独立反演并相互验证结果的准确性。

Significant errors may result when applying one dimensional (1-D) interpretation methods to magnetotelluric (MT) data collected in two dimensional (2-D) or three dimensional (3-D).Both resistivities and depths can be grossly incorrect if 1-D methods are applied in a 2-D or 3-D setting.Many methods to solve the existing problems can not be used practically beause of its computertime consumming and high costs and its strict application conditions.I suggest that the better methods can avoid complicated calculation such as finite elements,difference,integral equation etc.On the basis of the abstract to the 2-D or 3-D responses in the layered earth and the principles of fuzzy mathematics,I have developed a new method which has many advantages over exsisting ones:(1)It is able to eliminate 2-D or 3-D inhomogeneity effects and give a good and accurate 1-D geoelectric section.(2)It takes only a few minutes to complete an inversion on IBM/XT,so it can be easily applied to.practical work.However other methods spend about a few days inversing one 2-D geoelectric section's MT data on IBM/XT.(3)It is able to take into acount the both polarizations (TE and TM) at the same time,also inverse them respectively.The results can be verified by each other.(4)It has less problems of multiple solutions than other methods when processing MT data.