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A hydrogeological investigation using EM34 and SP surveys


EM34 and SP surveys were used to delineate shallow structures associated with the mineral water springs in the Vilarelho da Raia area located NE Portugal. This spring is part of a set of CO2-rich mineral (hot and cold) waters connected to the main Hercynian NNE-SSW fault systems. The EM34 survey was interpreted using a quasi-three-dimensional inversion approach based on a smooth-regularisation algorithm. The model put into evidence the conductive overburden as well as the fractured granitic formation. A preliminary estimation of the aquifer porosity is made based on the EM34 model. The SP anomalies were interpreted considering as having their sources on the aquifer interfaces. The modelling of two SP profiles allow the characterisation of a fault connected to the spring.


  1. Aires-Barros, L., J. M. Marques, and R. C. Graca, Elemental and isotopic geochemistry in the hydrothermal area of Chaves/Vila Pouca de Aguiar (Northern Portugal), Environmental Geology, 25(4), 232–238, 1995.

    Article  Google Scholar 

  2. Aires-Barros, L., J. M. Marques, R. C. Graca, M. J. Matias, C. H. van der Weijden, R. Kreulen, and H. G. M. Eggenkamp, Hot and cold CO2-rich mineral waters in Chaves geothermal area (northern Portugal), Geothermics, 27(1), 89–107, 1998.

    Article  Google Scholar 

  3. Astier, J. L., Geofisica Aplicada a la Hidrogeologia, 2nd edition, Paraninfo, Madrid, 1982.

    Google Scholar 

  4. Fitterman, D. V., Electrokinetic and magnetic anomalies associated with dilatent regions in a layered earth, J. Geophys. Res., 83, 5924–5934, 1978.

    Google Scholar 

  5. Fournier, C., Méthodes geoelectriques appliquées à l’hydrogéologie en région volcanique (Chaîne des Puys, Massif Central Francais). Développement de la méthode des potentiels spontanés en hydrogéologie. Thèse de 3eme cycle de Geologie, Universite des Sciences et Techniques du Languedoc (Montpellier II), 1983.

  6. Fournier, C., Spontaneous Potentials and resistivity surveys applied to hydrogeology in a volcanic area: case history of the Chaîne des Puys (Puyde-Dôme, France), Geophysical Prospecting, 37, 647–668, 1989.

    Article  Google Scholar 

  7. Marques, J. M., F. A. Monteiro Santos, R. C. Graa, R. Castro, L. Aires-Barros, and L. A. Mendes-Victor, A Geochemical and geophysical approach to derive a conceptual circulation model of CO2-Rich mineral waters: a case study of Vilarelho da Raia (NE Portugal), Hydrogeology Journal, 9, 584–596, 2001.

    Article  Google Scholar 

  8. McNeill, J. D., Electromagnetic terrain conductivity measurements at low induction numbers, Geonics Limited, Technical Note TN-6, 1980.

  9. McNeill, J. D., Use of electromagnetic methods for groundwater studies, in Geotechnical and Environmental Geophysics, edited by S. Ward, Society of Exploration Geophysicists, Investigations in Geophysics no. 5, 191–218, 1990.

    Google Scholar 

  10. Monteiro Santos, F. A., A. Dupis, A. R. Andrade Afonso, and L. A. Mendes-Victor, Magnetotelluric observations over the Chaves geothermal field (NE Portugal)-preliminary results, Phys. Earth Planet. Inter., 91, 203–211, 1995.

    Article  Google Scholar 

  11. Monteiro Santos, F. A., A. Dupis, A. R. Andrade Afonso, and L. A. Mendes-Victor, An audiomagnetotelluric survey over the Chaves geothermal field (NE Portugal), Geothermics, 25(3), 389–406, 1996.

    Article  Google Scholar 

  12. Monteiro Santos, F. A., H. Matias, and R. Gonalves, The use of EM34-3 surveys in cave detection, European Journal of Environmental and Engineering Geophysic, 6, 153–166, 2001.

    Google Scholar 

  13. Ogilvy, A. A., M. A. Ayed, and V. A. Bogolovsky, Geophysical studies of water leakage from reservoirs, Geophysical Prospecting, 28, 792–804, 1969.

    Google Scholar 

  14. Portugal Ferreira, M., A. Sousa Oliveira, and A. N. Trota, Chaves geothermal pole. Geological Survey, I and II. Joule I Program, DGXII, CEE. UTAD (Universidade de Tras-os-Montes e Alto Douro) internal report, 1992.

  15. Pozzi, J. P. and L. Jouniaux, Effets électriques des circulations de fluides dans les roches sedimentaires et prevision des séismes, C. R. Acad. Sci. Paris, t. 318, serie II, 73–77, 1994.

  16. Sasaki, Y., Two-dimensional joint inversion of magnetotelluric and dipole-dipole resistivity data, Geophysics, 54, 254–262, 1989.

    Article  Google Scholar 

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Correspondence to Fernando A. Monteiro Santos.

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Santos, F.A.M., Almeida, E.P., Castro, R. et al. A hydrogeological investigation using EM34 and SP surveys. Earth Planet Sp 54, 655–662 (2002).

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  • Hydrogeological Investigation
  • Electrokinetic Phenomenon
  • Aquifer Interface
  • Thermomineral Water
  • Shallow Circulation