Fracture aquifers are actual major issue in hydrogeology. They are an essential resource for many populations around the world. The present study focuses on major fractures that control groundwater and surface water flow, and play a key role in the productivity of fractured reservoirs. The use of numerical processing techniques (Selective Principal Component Analysis (SPCA), band ratios) and directional filtering by Sobel and Yésou allowed the identification of major fractures in the Black Volta Basin in Côte d’Ivoire. Validation of the latter was done by several field works (geology, hydrogeology and geomorphology) and a comparative analysis. Three groups of NS, NE-SW and E-W lineament directions were identified from these images. The structural field data generally indicate similar directions. Field data and satellite image processing show that most of these lineaments correspond to either shear faults or veins related to Eburnian and post-Eburnian orogenic events. The comparative analysis carried out revealed concordances with previous studies and automatically detected structures in the same area. The final lineament map generated for the study area will help to identify potential areas for drilling for water supply purposes.

Prospecting for groundwater resources is a problem in the Donga Department (North-West Benin) to satisfy people's water needs. Remote sensing remains essential for the mapping of water presence indicators, which are linear structures. The present study proposes to map the major fractures of North-West Benin from Landsat-8 OLI images and to use field data to characterize them. The use of spatio-directionnel filtering methods of Sobel and gradient and the techniques of Selective Principal Components Analysis allowed the creation of the major lineaments map. The validation of these last ones was carried out by several field works (geology, hydrogeology, geomorphology and botany). These data were superimposed in a GIS. After treatment, the obtained card counts 745 major fractures. This approach allowed to discriminate three major types of fractures. Fractures marked by vegetation alignments (type A) are the most abundant and occupy 60% of the area of the Donga Department. Fractures related to geological formations (type B) occupy 20% of the area of the study area and correspond to strike-out and shearing structures. The fractures indicated by the rectilinear cornices of lateritic cuirass (type C) correspond to late faults. The study of the directional distribution of outcrop fractures shows that the major directions are N-S (27%) and NE-SO (24%). This map will serve as a background document for future hydrogeological surveys in the region.