Electrical resistivity tomography (ERT) is one of the most effective geophysical methods used to acquire detailed pictures of subsurface conditions without drilling. Site investigation using two- and three-dimensional electrical resistivity imaging is now a fundamental step before the design and construction of campus buildings at the University of Sohag in Egypt. In this study, an ERT survey was implemented at two pre-defined sites with the aim of selecting the most favorable location for construction of a new educational building on the university campus. The resistivity results were confirmed with boreholes drilled at both sites. RES2DINV and RES3DINV software were used for data processing and interpretation. The results show that the near surface sedimentary succession beneath both sites consists of four geoelectrical and lithological units. From the surface to a depth of 20 m, these layers are: unit 1) unconsolidated boulders and gravels intercalated with percentages of sand and reddish clay; unit 2) fine crushed calcareous gravels and sands with clays intercalations; unit 3) dry sand and clayey sand; and unit 4) shale, at the base. According to an evaluation of the presence and abundance of shale and sand contents cracks, fissures and faults, the second site is identified as more suitable for construction.
Characterization of groundwater and surface water mixing in a semiconfined karst aquifer using time-lapse electrical resistivity tomography
