Use of Landsat-8 OLI data for delineating fracture systems in subsoil regions: implications for groundwater prospection in the Waddai area, eastern Chad

The use of satellite images for mapping and analyzing linear structures and fracture systems in subsoil regions is essential to understand the subsurface groundwater path ways and traps. In this study, we apply Optimal Index Factor (OIF), principal component analysis (PCA), and directional filtering (Sobel) of several Landsat 8 bands for the wooded Waddai area in NE Chad. The application of the Sobel directional filter to these bands showed a robust performance for enhancing the discontinuity features and allowed better identification of the fault/fracture systems by the automated lineament extraction techniques. The results indicate that the ENE and WSW structural trends control the distribution and migration of groundwater, in good agreement with previous hydrological studies and published hydrogeological maps. New highly potential areas for groundwater exploration are identified on a lineament density map and verified by ground truth urban distribution.