Special Issue: Electromagnetic Induction in the Earth
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Disturbances on magnetotelluric data due to DC electrified railway: A case study from southeastern Brazil
Earth, Planets and Space volume 54, pages 591–596 (2002)
Abstract
Magnetotelluric (MT) soundings were carried out in the period range of 20 to 6000 s along profiles roughly orthogonal to the Campos do Jordão Railway (CJRW), in the Brazilian southeastern region. The profiles were located over two adjacent regions with contrasting conductivity, the conductive sedimentary region of the Taubaté Basin and the resistive crystalline region of the Serra da Mantiqueira. The railway operates with DC current that produces an intense electromagnetic noise but only during diurnal periods, being turned off at night. The objective of this study is to characterize the CJRW noise in order to verify its effect on MT parameters. It was inferred that the entire length of the Taubaté Basin is probably affected by the noise, whereas in the crystalline terrains the noise reaches distances in the range of 76 to 126 km. The electric channels show a strong dependence on geology which is suggestive of the potential application of the CJRW as a controlled source in geophysical studies. The data were processed with modern techniques presently available to the scientific community. Under the conditions of the present study, it was observed that the robust Single Station technique is as efficient as the robust Remote Reference to remove the kind of noise generated by the CJRW, an intense perturbation that affects only some well-defined portions of the time series. Finally, the analyses reaffirm the necessity of a careful choice of the station to be used as reference in the Remote Reference technique.
References
Chave, A. D., D. J. Thomson, and M. E. Ander, On the robust estimation of power spectra, coherences, and transfer functions, J. Geophys. Res., 92, 633–648, 1987.
Egbert, G. D., Robust multiple-station magnetotelluric data processing, Geophys. J. Int., 130, 475–496, 1997.
Egbert, G. D. and J. R. Booker, Robust estimation of geomagnetic transfer functions, Geophys. J. R. Astron. Soc., 87, 173–194, 1986.
Egbert, G. D., M. Eisel, O. S. Boyd, and H. F. Morrison, DC trains and Pc3s: Source effects in mid-latitude geomagnetic transfer functions, Geophys. Res. Lett., 27, 25–28, 2000.
Fontes, S. L., Electromagnetic induction studies in the Italian Alps, Ph.D. thesis, Univ. of Edinburgh, 351 pp., 1988.
Fraser, B. J. and C. D. Ellyett, Man-made magnetic micropulsations, J. Geophys. Res., 69, 3603–3606, 1964.
Gamble, T. D., W. M. Goubau, and J. Clarke, Magnetotellurics with a remote magnetic reference, Geophysics, 44, 53–68, 1979.
Goldstein, M. A. and D. W. Strangway, Audio-frequency magnetotellurics with a grounded electric dipole source, Geophysics, 40, 669–683, 1975.
Jones, A. G. and H. Jodicke, Magnetotelluric transfer function estimation improvement by a coherence-based rejection technique, paper presented at 54th Annual International Meeting., Soc. of Expl. Geophys., Atlanta, Ga., Dec. 2–6, 1984.
Jones, F. W. and A. M. Kelly, Man-made telluric micropulsations, Can. J. Phys., 44, 3025–3031, 1966.
Jones, A. G., A. D. Chave, G. Egbert, D. Auld, and K. Bahr, A comparison of techniques for magnetotelluric response function estimation, J. Geophys. Res., 94, 14201–14213, 1989.
Junge, A., Characterization of and correction for cultural noise, Surv. Geophys., 17, 361–391, 1996.
Larsen, J. C., Transfer functions: smooth robust estimates by least-squares and remote reference methods, Geophys. J. Int., 99, 645–663, 1989.
Marques, A., Evolução tectono-sedimentar e perspectivas exploratórias da Bacia de Taubaté, São Paulo, Brasil, Bol. Geoc. Petrobrás, 4, 253–262, 1990.
Mikerina, N. V., The study of interference at the Voyeykovo magnetic observatory, Geomagn. Aeron., 2, 941–944, 1962.
Padilha, A. L. and Í. Vitorello, Investigacoes geoelétricas nas bacias de Taubate, Volta Redonda e Resende, Exp. Abst. 37th Cong. Bras. Geologia, 2, 403–404, 1992.
Padilha, A. L., N. B. Trivedi, Í. Vitorello, and J. M. Da Costa, Geophysical constraints on tectonic models of the Taubaté Basin, southeastern Brazil, Tectonophys., 196, 157–172, 1991.
Qian, W. and L. B. Pedersen, Industrial interference magnetotellurics: an example from the Tangshan area, China, Geophysics, 56, 265–273, 1991.
RADAMBRASIL, Levantamento dos recursos minerais (Mapa geologico 1:1,000,000), RADAMBRASIL, Rio de Janeiro, 1983.
Sims, W. E., F. X. Bostick, Jr., and H. W. Smith, The estimation of magnetotelluric impedance tensor elements from measured data, Geophysics, 36, 938–942, 1971.
Szarka, L., Geophysics aspects of man-made electromagnetic noise in the earth: a review, Surv. Geophys., 9, 287–318, 1988.
Yanagihara, K., Magnetic field disturbance produced by electric railway, Mem. Kakioka Mag. Obs., 38, 17–34, 1977.
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Pádua, M.B., Padilha, A.L. & Vitorello, Í. Disturbances on magnetotelluric data due to DC electrified railway: A case study from southeastern Brazil. Earth Planet Sp 54, 591–596 (2002). https://doi.org/10.1186/BF03353047
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DOI: https://doi.org/10.1186/BF03353047