Two-Dimensional Inversion of Magnetotelluric Data in the Study of Three-Dimensional Media

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Resumo

A three-dimensional geoelectric model of the tectonosphere has been constructed, containing typical geoelectric heterogeneities at three structural levels: the uplift and depression of the basement roof, conductive prisms in the consolidated crust, and the asthenospheric uplift in the upper mantle. Synthetic magnetotelluric data have been calculated and their sensitivity to geoelectric structures has been analyzed. A two-dimensional smoothing inversion of the synthetic data has been performed along two perpendicular profiles. Despite significant three-dimensional effects, the position of the basement roof has been reconstructed quite accurately in the obtained sections, rough images of crustal structures have been obtained, and the mantle structure is poorly resolved. The influence of random noise of various levels on the inversion results has been estimated. In the future, a three-dimensional inversion of the synthetic data is planned.

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Sobre autores

D. Popov

Lomonosov Moscow State University

Autor responsável pela correspondência
Email: crossbrian97@mail.ru

Faculty of Geology

Rússia, Moscow

P. Pushkarev

Lomonosov Moscow State University

Email: pavel_pushkarev@list.ru

Faculty of Geology

Rússia, Moscow

Bibliografia

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2. Fig. 1. Section of the sedimentary cover along the central meridional profile.

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3. Fig. 2. Map of the total longitudinal conductivity of the sedimentary cover.

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4. Fig. 3. Map of the location of conducting prisms in the consolidated crust.

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5. 4. Deep sections along the central meridional and latitudinal profiles, reflecting the position of conducting crustal prisms and asthenospheric uplift.

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6. Fig. 5. Maps of the UES at a depth of 60 km (the roof of the asthenospheric uplift) and 120 km (the base of the uplift).

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7. 6. Amplitude (a) and phase (b) Zeff curves, central meridional profile.

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8. 7. Amplitude (a) and phase (b) Zeff curves, central latitudinal profile.

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9. 8. Maps of the polar diagrams |Zxy| and |Zxx|. On the left is a period of 21.5 s, on the right — 464 s.

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10. 9. Maps of induction arrows: real ReW (red) and imaginary ImW (green). On the left is a period of 21.5 s, on the right — 464 s.

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11. Fig. 10. Pseudo-sections of the parameters N, skewS, skewB and α.

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12. 11. Geoelectric sections up to a depth of 5 km along the central meridional profile according to: (a) — Z⊥; (b) — arg(Z; (c) - jointly Z⊥ and W��. The white line is the true position of the roof of the foundation.

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13. Fig. 12. Geoelectric sections up to a depth of 100 km along the central meridional profile according to: (a) — Zeff; (b) — Z⊥; (c) — arg(Z. The dotted line represents the true boundaries.

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14. Fig. 13. Geoelectric sections up to a depth of 100 km along the central latitudinal profile according to: (a) — Zeff; (b) — Z⊥; (c) — arg(Z. The dotted line represents the true boundaries.

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15. Fig. 14. Geoelectric sections up to a depth of 100 km along the central meridional (a) and (b) and latitudinal (c) and (d) profiles according to the data of joint inversion: (a) and (c) — Zeff and W (b) and (d) - Z⊥ and W. The dotted line represents the true boundaries.

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16. 15. Geoelectric sections up to a depth of 100 km along the central meridian profile according to Z⊥ data with different noise levels: (a) - 0%; (b) — 2%; (c) — 5%; (d) — 10%; (e) — 20%. The dotted line shows the true boundaries.

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