Navegar

Colección

Datos Estadísticas

Artículo

Este artículo es de Acceso Abierto y puede ser descargado en su versión final desde nuestro repositorio
Consulte el artículo en la página del editor
Consulte la política de Acceso Abierto del editor

Abstract:

In previous works, we presented 2-D and 3-D magnetotelluric modelling methods based on Rayleigh-Fourier expansions. These methods are an alternative to finite-element and finite-difference techniques and are especially suitable for modelling multilayered structures, with smooth irregular boundaries. Here we generalize the 2-D method for the calculation of the electromagnetic response of 2-D structures to arbitrary, spatially non-uniform 2-D and 3-D inducing magnetic fields. These fields are characteristic of low- and high-latitude regions. We calculate the response to different 2-D and 3-D sources, of a 2-D structure representative of the conductivity distribution which could be found at a coastline, which includes deep conductive anomalies in the lower crust and upper mantle. Then, we investigate source effects, comparing these responses to that obtained for a uniform source. These effects become noticeable for periods greater than approximately 6 h and increase with the period of the source. They are highly dependent on the morphology of the source and also on the orientation of the external field relative to the strike direction of the structure. In various cases, they totally mask the uniform source response.

Registro:

Documento: Artículo
Título:Modelling electromagnetic responses of 2-D structures due to spatially non-uniform inducing fields. Analysis of magnetotelluric source effects at coastlines
Autor:Martinelli, P.; Osella, A.
Filiación:Dto de Fisica, Fac. Cs. Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
Palabras clave:Daily variations; Geo-electromagnetic induction; Non-uniform inducing fields; Source effects; coastal morphology; electromagnetic method; induced polarization; magnetotelluric method
Año:2003
Volumen:155
Número:2
Página de inicio:623
Página de fin:640
DOI: http://dx.doi.org/10.1046/j.1365-246X.2003.02072.x
Título revista:Geophysical Journal International
Título revista abreviado:Geophys. J. Int.
ISSN:0956540X
PDF:https://bibliotecadigital.exactas.uba.ar/download/paper/paper_0956540X_v155_n2_p623_Martinelli.pdf
Registro:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0956540X_v155_n2_p623_Martinelli

Referencias:

  • Bahr, K., Filloux, J.H., Local Sq responses from EMSLAB data (1989) J. Geophys. Res., 95, pp. 14195-14200
  • Boteler, D.H., Pirjola, R., The complex-image method for calculating the magnetic and electric fields at the surface of the Earth by the auroral electrojet (1998) Geophys. J. Int., 132, pp. 31-40
  • Cagniard, L., Basic theory of the magnetotelluric method of geophysical prospecting (1953) Geophysics, 18, pp. 605-635
  • Carrasquilla, A., Rijo, L., Analysis of electrojet-distorted magnetotelluric sounding curves (1998) J. Appl. Geophys., 40, pp. 187-204
  • Dimitriev, V.I., Berdichevsky, M.N., The fundamental model of magnetotelluric sounding (1979) Proc. IEEE, 67, pp. 1033-1044
  • Favetto, A., Martinelli, P., Osella, A., Electrical and thermal anomalies in the Central Andean subduction zone (1997) Pure Appl. Geophys., 149, pp. 391-404
  • Gough, D.I., McKirdy, D.M., Woods, D.V., Geiger, H., Conductive structures and tectonics beneath the EMSLAB land array (1989) J. Geophys. Res., 94, pp. 14099-14110
  • Häkkinen, L., Pirjola, R., Calculation of electric and magnetic fields due to an electrojet current system above a layered earth (1986) Geophysica, 22, pp. 31-44
  • Korja, T., BEAR. Baltic Electromagnetic Array Research (1998) Europrobe News, 12, pp. 4-5. , and the BEAR Working Group
  • Mareschal, M., Source effects an the interpretation of geomagnetic sounding data at sub-auroral latitudes (1981) Geophys. J. R. Astr. Soc., 67, pp. 125-136
  • Martinelli, P., Osella, A., MT forward modeling of 3D anisotropic electrical conductivity structures using the Rayleigh-Fourier method (1997) J. Geomag. Geoelectr., 49, pp. 1499-1518
  • Osella, A., Martinelli, P., Magnetotelluric response of anisotropic 2-D structures (1993) Geophys. J. Int., 115, pp. 819-828
  • Osella, A.M., Favetto, A., Martinelli, P., Sensitivity of the geomagnetic daily variations to 2-D structures (1993) Trends Geophys. Res., 2, pp. 141-155
  • Osella, A.M., Favetto, A., Martinelli, P., Lateral heterogeneitics in the upper and mid-mantle conductivity in Argentina (1993) Pure Appl. Geophys., 141, pp. 139-156
  • Osipova, I.L., Hjelt, S.E., Vanyan, L.L., Source field problems in northern parts of the Baltic Shield (1989) Phys. Earth Planet. Inter., 53, pp. 337-342
  • Padilha, A.L., Vitorello, I., Rijo, L., Effects of the equatorial electrojet on magnetotelluric surveys; field results from Northwest Brazil (1997) Geophys. Res. Lett., 24, pp. 89-92
  • Pirjola, R., On magnetotelluric source effects caused by an auroral electrojet system (1992) Radio Sci., 27, pp. 463-468
  • Pirjola, R., Vilhanen, A., Complex image method for calculating electric and magnetic fields produced by an auroral electrojet of a finite length (1998) Ann. Geophys., 16, pp. 1434-1444
  • Quon, C., Vozoff, K., Hoversten, M., Morrison, H.F., Lee, K.-H., Localized source effects on magnetotelluric apparent resistivities (1979) J. Geophys., 46, pp. 291-299
  • Schultz, A., Larsen, J.C., On the electrical conductivity of the Earth's interior I: Mid-mantle response function computation (1987) Geophys. J. R. Astr. Soc., 88, pp. 763-781
  • Smith, J.T., Booker, J.R., Rapid inversion of two and three-dimensional magnetotelluric data (1991) J. Geophys. Res., 96, pp. 3905-3922
  • Srivrastava, S.P., Methods of interpretation of magnetotelluric data when source field is considered (1965) J. Geophys. Res., 70, pp. 945-954
  • Tikhonov, A.N., On determining electrical characteristics of the deep layers of the Earth's crust (1950) Doklady, 73, pp. 295-297
  • Vilhanen, A., Source effect on geomagnetic induction vectors in the Fennoscadian Auroral Region (1996) J. Geomag. Geoelectr., 48, pp. 1001-1009
  • Vilhanen, A., Pirjola, R., Häkkinen, L., An attempt to reduce induction source effects at high latitudes (1993) J. Geomag. Geoelectr., 45, pp. 817-831
  • Vilhanen, A., Pirjola, R., Amm, O., Magnetotelluric source effect due to 3D ionospheric current systems using the complex image method for ID conductivity structures (1999) Earth Planets Space, 51, pp. 933-945
  • Wait, J.R., Spies, K.P., On the representation of the quasi-static fields of a line current source above the ground (1969) Can. J. Phys., 27, pp. 2731-2733
  • Wannamaker, P.E., Hohmann, G.W., San Filipo, W.A., Electromagnetic modeling of 3D bodies in layered earths using integral equations (1984) Geophysics, 49, pp. 60-74
  • Wannamaker, P., Stodt, J., Rijo, L., A stable finite element solution for two-dimensional magnetotelluric modeling (1987) Geophys. J. R. Astr. Soc., 88, pp. 277-296
  • Weaver, J.T., (1994) Mathematical Methods for Geo-electromagnetic Induction, p. 316. , Wiley, Taunton

Citas:

---------- APA ----------
Martinelli, P. & Osella, A. (2003) . Modelling electromagnetic responses of 2-D structures due to spatially non-uniform inducing fields. Analysis of magnetotelluric source effects at coastlines. Geophysical Journal International, 155(2), 623-640.
http://dx.doi.org/10.1046/j.1365-246X.2003.02072.x
---------- CHICAGO ----------
Martinelli, P., Osella, A. "Modelling electromagnetic responses of 2-D structures due to spatially non-uniform inducing fields. Analysis of magnetotelluric source effects at coastlines" . Geophysical Journal International 155, no. 2 (2003) : 623-640.
http://dx.doi.org/10.1046/j.1365-246X.2003.02072.x
---------- MLA ----------
Martinelli, P., Osella, A. "Modelling electromagnetic responses of 2-D structures due to spatially non-uniform inducing fields. Analysis of magnetotelluric source effects at coastlines" . Geophysical Journal International, vol. 155, no. 2, 2003, pp. 623-640.
http://dx.doi.org/10.1046/j.1365-246X.2003.02072.x
---------- VANCOUVER ----------
Martinelli, P., Osella, A. Modelling electromagnetic responses of 2-D structures due to spatially non-uniform inducing fields. Analysis of magnetotelluric source effects at coastlines. Geophys. J. Int. 2003;155(2):623-640.
http://dx.doi.org/10.1046/j.1365-246X.2003.02072.x