Using the pseudo-tipper data of magnetotelluric sounding to study fault

摘要

The mathematical & physical principle as well as the definition of the pseudo-tipper is put forward for the first time in this paper based on the definition of tipper in magnetotelluric survey. The pseudo-tipper can be directly calculated from the apparent resistivity and phase curves, so the disadvantages of the low-quality field-observed tipper that could not be used for further interpretation is avoided. The characteristics of the pseudo-tipper parameters are systematically studied through the analyses of various kinds of models. Horizontal heterogeneity of the geo-electrical structures, especially the fault with its dip-direction, position, size, buried depth and the electric-property contrast, could all be revealed by pseudo-tipper' s module, phase, real & imaginary parts and the new-advanced analogy inversion approach following the Bostick method. Furthermore, combining with the processing and correlation of the field observed MT tipper data, it has a quite good agreement with the pseudo-tipper and the interpretation result also represents the good effects of this method. Generally speaking, without any prior information, the studies we made produce a new approach for the direct determination of inhomogeneous geo-electrical structure and particularly the features of the fault, which provides more accurate information for the further studies of geological interpretation.