Research on Inversion Resolution for ERT Data and Applications for Mineral Exploration

  • Author(s): Gang Zhang, Gui-Bin Zhang, Chien-Chih Chen, and Zheng-Yuan Jia
  • DOI: 10.3319/TAO.2015.05.06.01(T)
  • Keywords: Resolution, Electrical resistivity tomography, Numerical simulations, Parallel processing, Mineral exploration

This paper presents the effects of two factors on electrical resistivity tomography (ERT) resolution using numerical simulations. The results obtained from the first group of synthetic resistivity model numerical simulations with different electrode configurations illustrate that the inversion resolution can be improved if the current electrodes and potential electrodes are installed at a subsurface depth. The results obtained from the second group of synthetic resistivity models with different mesh densities illustrate that the inversion resolution can be improved if the mesh grid density is increased. The increased number of degrees of freedom necessary to fit the data to a prescribed target misfit leads to the inverted imagery deviating from the true resistivity model. Throughout the literature the inversion procedure is implemented in the conjugate gradient relaxation method and the model calculation speed is enhanced using the parallel processing mode. ERT surveys were employed for mineral exploration at Chifeng in Inner Mongolia, China. The inverted image clearly describes the vein behavior down to 200 m in depth in the prospect area and is consistent with the drilling data results.

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