Japan Geoscience Union Meeting 2023

Presentation information

[E] Online Poster

S (Solid Earth Sciences ) » S-EM Earth's Electromagnetism

[S-EM14] Electric, magnetic and electromagnetic survey technologies and scientific achievements

Wed. May 24, 2023 1:45 PM - 3:15 PM Online Poster Zoom Room (4) (Online Poster)

convener:Kiyoshi Baba(Earthquake Research Institute, The University of Tokyo), Tada-nori Goto(Graduate School of Science, University of Hyogo), Yuguo Li(Ocean University of China), Wiebke Heise(GNS Science, PO Box 30368, Lower Hutt, New Zealand)

On-site poster schedule(2023/5/23 17:15-18:45)

1:45 PM - 3:15 PM

[SEM14-P06] Distortion decomposition of MT impedance tensors in 1D anisotropic media

*Tianyi Dai1, Yuguo Li1 (1.Ocean University of China)


Keywords:Magnetotelluric, Electromagnetic field, Distortion decomposition, Electrical anisotropy

The electromagnetic local distortions due to shallow local small-scale inhomogeneities are the major problem for accurate interpretation of Magnetotelluric (MT) data. These distortions can be galvanic and inductive. Decomposition techniques of MT impedance tensor that only consider galvanic distortion and ignore inductive distortion have been well developed, under the assumption that subsurface electrical structures are electrically isotropic. In this paper, we present a decomposition method of MT impedance tensors in 1D conductivity anisotropic media, in which both the electric field galvanic distortion and the associated magnetic distortion are taken into consideration. Regional anisotropic responses and electromagnetic distortion parameters are recovered by using the Quasi-Newton BFGS algorithm with the aid of phase tensor analysis and trust region method. The model studies indicate that the inclusion of magnetic galvanic distortion in conventional decomposition of MT impedance tensors is necessary and essential for subsequent procedures. The decomposition method is also employed in the processing of BC87 data set, demonstrating the significance of considering regional electric anisotropy.