One-dimensional Laterally Constrained Joint Anisotropic Inversion of CSRMT and ERT Data

Abstract

In this paper, we discuss several approaches for a joint inversion of controlled source radiomagnetotelluric (CSRMT) and electrical resistivity tomography (ERT) data observed over anisotropic media. We compare results of 2D isotropic joint inversion with results of a newly developed joint 1D anisotropic inversion algorithm. The developed algorithm involves the full controlled source high frequency forward and inversion formulations without the plane wave assumption. We demonstrate that for measurements on an anisotropic subsurface the isotropic joint inversion cannot fit both datasets properly due to a high anisotropy of shallow horizons of quaternary sands and loams. The joint anisotropic inversion helps to solve this problem and highlights the advantages of a joint inversion of CSRMT and ERT data. We also demonstrate application of the laterally constrain algorithm for the anisotropic inversion. Results of the joint 1D anisotropic inversion of CSRMT and ERT data were successfully compared with existing borehole data.

Novel approach in static shift correction for magnetotellurics data using 2D electrical resistivity imaging

“…ZondMT2D was chosen in this study for processing and interpretation of the MT data for one-and twodimensional model (Saraev et al, 2020;Shlykov et al, 2021). Coordinate of every MT station was inserted into the software to generate a 2-dimensional pro le.…”

Use of Subharmonics of Base Frequencies in the CSRMT Method with Loop Sources

“…In recent years, the tensor variant of the CSRMT method, using two mutually perpendicular HEDs as electromagnetic field sources, has been developed jointly by the University of Cologne and St. Petersburg State University. New possibilities of the tensor technology have been demonstrated in studies of rock anisotropy [18][19][20] and of objects in permafrost areas [21,22]. To implement the tensor variant with two HED sources, approaches have been developed to create a rotating electromagnetic field [23].…”

“…Along with the soundings in the far-field zone, the techniques and software tools were elaborated to use the HED source in the transition zone. Examples of the bimodal inversion of field data using the tensor variant of the CSRMT method in the transition zone have been reported in articles [19,24].…”

“…The use of sources of different types can be useful for increasing the reliability of the obtained resistivity models as well as for estimating the anisotropy of resistivity. The results of studies of rock anisotropy using the CSRMT method with HED were considered in our previous papers [18][19][20]32].…”