Abstract: Mathematical formulas of three-dimensional(3D) Magnetotelluric(MT) responses affected by shear,twist and anisotropy are derived based on the principle of two-dimensional(2D) MT impedance tensor decomposition,which are applicable not only to complicated 3D structure,but also to 2D or 1D situations.Mohr circle analysis are also made for 3D MT responses and the properties in the cases of both weak and strong distortions.

Key words: Magnetotelluric sounding, Impedance tensor, Mohr circle, Distortion effect

摘要： 根据二维大地电磁阻抗张量分解原理,推导出剪切、扭曲和各向异性因素影响区域性三维响应的关系式。这既适用于任意复杂的三维构造,也包含了二维和一维情况。并用Mohr圆分析了受畸变因素影响时的三维响应及其在微弱畸变与强烈畸变影响下不同的性质和特征。

关键词: 大地电磁测深, 阻抗张量, 莫尔圆, 畸变效应