Electrical and Electromagnetic Resistivity Imaging Environmental Applications and Engineering Study

A frequency-domain electromagnetic (FDEM) and electrical resistivity imaging (ERI) surveys can be used for delineating underground cavities and characterizing pseudo-karst dissolution of limestone sandstone on the northwest of Algiers. This site has complex geology still requires a detailed survey prior to the execution of civil works. The FDEM survey was performed using both a very low frequency resistivity (VLFR) and a controlled source EM system (Geonis EM31). The electrical resistivity imaging has been conducted using dipole-dipole array. The results of this study have identified a number of karst cavities in the calcareous sandstone associated with carbonate dissolution by groundwater from a depth of about 4 m, some of these cavities and fracture zones were identified by boreholes at the site. The networks of cavities are organized along a N110 ° and N60 °.