COUPLING ELECTRICAL TOMOGRAPHY AND VLF ELECTROMAGNETIC GEOPHYSICAL METHODS TO DETECT WATER-BEARING FRACTURED ZONES AT THE CAUSSE OF EL HAJEB (MOROCCO)

The Causse of El Hajeb-Ifrane is a part of the Northern Middle Atlas Causse and known for its Jurassic limestone formation which drains groundwater towards the plain of Saïss. In order to identify a water-bearing and to understand the flows at the bottom of the Causse of El Hajeb, a geophysical survey including two Electrical Resistivity Tomography profiles with perpendicular directions (N-S and E-W), and two profiles of VLF (Very Low Frequency) electromagnetism for 450m length and steps of 10m have been made. The analysis and comparison of all these results allowed us to identify a set of anomalies that may possibly correspond to fractured zones draining groundwater from the plateau of El Hajeb to the plain of Saïss.
This area is under over-farming, causing pollution of the aquifer by the use of agricultural products, that’s why we have chosen this study area in order to determine the fractured zone draining this pollution.