Contribution of remote sensing and GIS to the mapping of geological structures in the Mô Basin, Togo: Hydrogeological implications (West Africa)

This research aims to detect subsurface discontinuities influencing groundwater flow in the Mô watershed by integrating gravimetric anomaly processing and SRTM Digital Elevation Model (DEM) analysis within a GIS framework. Gravity data from Geosoft Oasis Montaj underwent advanced filtering including reduction to the equator, vertical/horizontal derivatives, Tilt derivative, analytic signal, and Euler deconvolution to extract geostructural information. Concurrently, the DEM was processed via solar and angular shaded relief to identify geomorphological lineaments, which were then validated against existing geological maps. Results reveal a heterogeneous structural distribution, with major gravity anomalies aligned NNE-SSW and E-W, while weaker anomalies correspond to sediments and alluvium. Fracture orientations varied by method: horizontal derivatives highlighted N-S structures, vertical derivatives and analytic signals indicated NNW-SSE and N-S trends, and the Tilt derivative exposed NNE-SSW and E-W axes. SRTM data extracted multi-directional lineaments, with notable convergence for N-S, NNE-SSW, and NE-SW directions across both datasets. This alignment confirms these structures' linkage to the Pan-African orogeny in the Dahomeyide Belt. The integrated, synergistic approach combining Euler deconvolution and Tilt derivative with high-resolution DEM lineaments is a key advancement over prior isolated methodologies. This study serves dual objectives: geologically, it refines understanding of fracture networks controlled by Pan-African tectonics; hydrogeologically, it identifies major discontinuity orientations and high-gradient zones acting as preferential groundwater conduits. By mapping these zones, the research provides a critical decision-support tool to optimize future drilling campaigns, enhancing groundwater resource exploration in the region.