Details of the Abstract
| Title of paper | A potential function approach for modelling electromagnetic induction responses over Earth models with two-dimensional boundaries |
| List of authors | Long, Jianbo. Wang, Shunguo. |
| Affiliation(s) | Norwegian University of Science and Technology |
| Summary | Three-dimensional natural-source electromagnetic induction modelling typically uses one-dimensional background models for studying localized conductivity structures. In magnetotelluric data modelling, there are scenarios where exact two-dimensional boundary surfaces need to be honoured such as studying of terrain effects on the magnetotelluric data. Our focus in this study is about coastal and topographic (bathymetry) effects on marine magnetotelluric data where two-dimensional, exact boundaries are important. Due to the large scale characteristic of marine models, the standard Helmholtz equation for the electric field, which is frequently used for three-dimensional forward modelling of magnetotelluric data, becomes less favourable since it is indefinite and its resulting linear system of equations requires special efforts to be solved iteratively. By contrast, if potential field equations are used in the modelling, many common Krylov subspace iterative solvers can be directly applied to the solving of the resulting linear system. Current potential function approaches for the modelling of magnetotelluric data from the literature are limited to those only using one-dimensional background models (e.g., halfspace models) which cannot consider exact two-dimensional boundary surfaces, and hence will adversely introduce unreal terrain-caused distortions to the magnetotelluric data. In this study, we have developed a potential function-based modelling approach that can handle arbitrarily complex two-dimensional boundary surfaces for marine magnetotelluric data modelling. We demonstrate the effectiveness and accuracy of this new approach with a realistic marine conductivity model. |
| Session Keyword | 2.0 EM theory, modelling and Inversion |
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