Research paper
Study of the Chaves geothermal field using 3D resistivity modeling

https://doi.org/10.1016/S0926-9851(97)00010-4Get rights and content

Abstract

The present paper deals with the 3D modeling of a resistivity data set, carried out over the Chaves graben where the hot springs, with a temperature reaching 78°C, have a great economic importance. The main objective of the modeling was to incorporate the partial knowledge obtained from previous ID and 2D interpretations into a three dimensional model. The 3D models of three rectangles and two dipole-dipole surveys, which were performed to detect conductive zones associated with the hydrothermal circulation, depict the general form of the graben and the spatial configuration of the low resistivity zones (10–15 μ m). The achieved models exhibit several characteristics similar to those of previous 1D and 2D interpretations and are consistent with geological information and new findings related to the bed-rock depth (1200 to 1500 m), the northern and southern borders of the conductive zones and its connection with the fault systems.

References (17)

  • L. Aires-Barros et al.

    The low temperature geothermal system of Chaves (Northern Portugal): A geochemical approach

  • R.R. Andrade Afonso et al.

    The resistivity method in the evaluation of geothermal resources-application to Chaves (Portugal) geothermal field

  • M.R. Bakbak

    Three-dimensional modelling in resistivity and IP prospecting

  • D.L. Campbell

    Model for estimating electric macroanisotropy coefficient of aquifers with horizontal and vertical fractures

    Geophysics

    (1977)
  • A. Dey et al.

    Resistivity modelling for arbitrarily shaped three-dimensional bodies

    Geophysics

    (1979)
  • Hidroprojecto et al.

    Estudos das águas subterrâneas do vale de Chaves e seus vales secundários

    (1987)
  • H.K. Johansen

    A man/computer interpretation system for resistivity soundings over horizontally stratified earth

    Geophys. Prospect

    (1977)
  • F.A. Monteiro Santos et al.

    Magnetotelluric observations over the Chaves geothermal field (NE Portugal): Preliminary results

    Phys. Earth Planet. Inter.

    (1995)
There are more references available in the full text version of this article.

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