Contributions of Geophysics and Remote Sensing in the Mapping of Hydraulically Active Fractures in the Base Zone West of Kinshasa, DR-Congo

Abstract

The hills region is very famous west of Kinshasa, which is why its drinking water supply problems in the municipalities and various districts of NGALIEMA and MONT-NGAFULA, located in an area made up only of crystalline rocks. She is experiencing acute difficulties in accessing water resources. The objectives of this study is to map fracture networks from satellite images and to use electrical resistivity tomography for their location on the ground. The methodological approach used is based on the use of remote sensing techniques for structural lineament mapping and the application of electrical resistivity tomography for the validation of hydraulically active lineaments. The use of techniques of selective principal component analysis and directional spatial filtering of sobel made it possible to establish the map of major lineaments. The validation of the lineaments was made during several geophysical prospecting works of electrical resistivity tomography. The map generated following the processing of satellite images counts 65 linear structures whose size varies from 7 to 41 km and which have two preferential directions N 0 ° - N10 ° and N 80 ° - 90 °.

                    At the end of the geophysical work, 10 lineaments were validated as major fractures with altered cracked zone widths ranging from 15 to 40 m and whose depths are beyond 50 m. The range of electrical resistivity characterizing these fractures varies from 100 to 800 Ωm.