Three-dimensional inversion of CSAMT data in the presence of topography
Changhong Lin 1 2 Handong Tan 1 Wangwang Wang 1 Tuo Tong 1 Miao Peng 1 Mao Wang 1 Weihua Zeng 1
+ Author Affiliations
- Author Affiliations
1 School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing 100083, China.
2 Corresponding author. Email: linchh@cugb.edu.cn
Exploration Geophysics 49(3) 253-267 https://doi.org/10.1071/EG16067
Submitted: 15 June 2016 Accepted: 6 April 2017 Published: 23 May 2017
Abstract
3D controlled-source audio frequency magnetotelluric (CSAMT) responses can be distorted strongly by topography and should be accounted for in data inversion and interpretation. In this paper we present a scheme to incorporate topographic distortions into the inversion instead of correcting them. This approach has been verified by comparing the modelling results with 2D FEM CSAMT solutions and synthetic inversion examples. Compared with the responses generated from a half-space model with flat surface, it is found that not only the topography in the survey area but also that at the source position may strongly distort the CSAMT responses. The field example indicates that results with topography are much better than those without considering topography to map the distribution of coal seam underground, which also illustrates the effectiveness of our approach.
Key words: 3D inversion, CSAMT, topography.
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