Spaceborne Fracture Network Mapping for Appraising Slope Stability, Building Structural Integrity and Groundwater Potential Distribution in Lokoja, Nigeria

Abstract

Fracture mapping has been traditionally conducted from field geological studies but this has the limitation of covering only a small area and many fractures are missed in the process. The use of satellite images to extract lineaments that represent structural deformations can adequately compliment the tedious and time-consuming field mapping. The main objective of this research therefore is to produce a fracture network map (structural map) of the study area from satellite images (Sentinel-2A). Other objectives are to (1) assess the structural stability of hilly/mountainous areas currently faced with development pressure through the production of terrain stability map (2) assess current buildings structural integrity through the analysis of building deformity and (3) produce a city-wide groundwater potential map through analyses of lineament densities and slope gradients. Automatic lineament extraction identified 13 lineaments predominantly trending NE–SW, with higher densities around the southern and northeastern parts of the area. Slope analysis revealed steep gradients along the northern fringes associated with the Mount Patti ridge, while the remaining areas exhibited generally gentle slopes. Combining lineament density and slope data enabled the delineation of stable and unstable terrain for development. A structural assessment of 240 buildings indicated that most buildings with and without defects are located within the stable terrain, suggesting that additional factors such as construction quality may be influential. Groundwater potential mapping revealed high-potential zones in the southern, eastern, and northeastern areas where high lineament density coincides with low slope gradients. Validation using eleven boreholes yielded an accuracy of 64%, confirming the reliability of the integrated approach. Overall, the study demonstrates the effectiveness of combining multispectral remote sensing and GIS-based analysis for evaluating geomorphological hazards, supporting informed urban planning, and guiding groundwater resource development in Lokoja.