Application of 2D and 3D Geoelectrical Resistivity Imaging forudEngineering Site Investigation in a Crystalline Basement Terrain,udSouthwestern Nigeria

摘要

Orthogonal set of 2D geoelectrical resistivityudfield data, consisting of six parallel and five perpendicularudprofiles, were collected in an investigation site using theudconventional Wenner array. Seven Schlumberger soundingsudwere also conducted on the site to provide ID layeringudinformation and supplement the orthogonal 2D profiles.udThe observed 2D apparent resistivity data were first processedudindividually and then collated into 3D data setudwhich was processed using a 3D inversion code. The 3Dudmodel resistivity images obtained from the inversion areudpresented as horizontal depth slices. Some distortionsudobserved in the 2D images from the inversion of the 2Dudprofiles are not observed in the 2D images extracted fromudthe 3D inversion. The survey was conducted with the aimudof investigating the degree of weathering and fracturing inudthe weathered profile, and thereby ascertaining the suitabilityudof the site for engineering constructions as well asuddetermining its groundwater potential.