Joint application of seismic refraction and vertical electrical sounding for the delineation of shallow aquifers

Inversion of seismic refraction and vertical electrical sounding data alone may lead to incorrect parameter estimation in complex geological set-up, n amely, blind zone in seismics, suppression and equivalence in geoelectrics. A unique solution may be achieved by integrating physically different sets of data into a joint or sequential inversion scheme. In this paper we have introduced one such algorithm, wherein the seismic velocity-depth section from ray inversion guides the evolution of a well-resolved geoelectric sect ion in 2D environment from 1D DC resistivity inversion by evolutionary prog ramming, The synthetic models suffering from the suppression and equivalenc e problems could be successfully reconstructed using this approach. Three t est sites at Keshpal, Tata Metalik and Salboni in Midnapur District, West B engal were selected through remote sensing and GIS tools, By sequentially i nterpreting the seismic and resistivity data, we could delineate. a shallow aquifer with an average thickness of 6.8 m at Tata Metalik. At Salboni, ho wever, a thin aquifer at 46 m depth needed an additional electrolog/litholo g depth control for its delineation by the proposed joint approach.