Research paper
The inversion of geoelectrical data for hydrogeological applications in crystalline basement areas of Nigeria

https://doi.org/10.1016/S0926-9851(97)00005-0Get rights and content

Abstract

A methodology is presented for the inversion of two-dimensional (2-D) geoelectrical data for solving hydrogeological problems in crystalline basement areas. The initial step entails compiling an earth model using all available geological, borehole and geophysical information. This model then served as the input to a 2-D inversion algorithm based on the Simultaneous Iterative Reconstruction Technique (SIRT). The algorithm tries to find a model that is as close as possible to the starting model. To demonstrate the usefulness of this procedure, two field examples from Nigeria, conducted as part of a borehole siting programme, are described. In the first example, borehole information regarding the thickness of the weathered zone overlying a gneissic bedrock was used to constrain the 1-D inversion of sounding data and the model thus compiled was used as the starting model for 2-D inversion. In the second example, only sounding information was used to determine the starting model. If the starting model has incorporated all the available information as constraints, it is generally possible to compute a model that not only fits the measured data but is also a good approximation of the subsurface geology, more so when several 2-D models can fit the same set of field measurements on account of the limitations posed by equivalence.

References (26)

  • M. Dorn

    A special aspect of interpretation of geoelectrical sounding curves and its application for groundwater exploration

    Geoexploration

    (1985)
  • D.H. Griffiths et al.

    Two-dimensional resistivity imaging and modelling in areas of complex geology

    J. Appl. Geophys.

    (1993)
  • A. Aina et al.

    An integration of aeromagnetic and electrical resistivity methods in dam site investigation

    Geophysics

    (1996)
  • R.D. Barker

    The Offset System of electrical resistivity sounding and its use with a multicore cable

    Geophys. Prospect.

    (1981)
  • R.D. Barker

    A simple algorithm for electrical imaging of the subsurface

    First Break

    (1992)
  • P.J. Chilton et al.

    Hydrogeological characterisation and water supply potential of basement aquifers in tropical Africa

    Hydrogeol. J.

    (1995)
  • A. Dey et al.

    Resistivity modelling for arbitrarily shaped two-dimensional structures

    Geophys. Prospect.

    (1979)
  • K.A. Dines et al.

    Computerized geophysical tomography

  • L.S. Edwards

    A modified pseudosection for resistivity and induced polarisation

    Geophysics

    (1977)
  • R.G. Ellis et al.

    Applied geophysical inversion

    Geophys. J. Int.

    (1994)
  • M. Goldman et al.

    On reducing ambiguity in the interpretation of transient electromagnetic sounding data

    Geophys. Prospect.

    (1994)
  • D.H. Griffiths et al.

    A multi-electrode array for resistivity surveying

    First Break

    (1985)
  • D.H. Griffiths et al.

    Two-dimensional resistivity mapping with a computer controlled array

    First Break

    (1990)
  • Cited by (0)

    View full text