The aeromagnetic data of Nsukka area was interpreted qualitatively and quantitatively. Standard Euler deconvolution, Source Parameter Imaging (SPI), Forward and Inverse modeling techniques were employed in quantitative interpretation with the aim of determining depth/thickness of the sedimentary Basin, magnetic susceptibilities and type of mineralization prevalent in the area. Oasis montaj 6.4.2 software and potent Q 4.10.07 software were employed in the data analysis. Forward and inverse modeling estimated depths for profiles 1, 2, 3, 4 and 5 were 1644, 2285, 1972, 2193 and 1200 m respectively, with respective susceptibility values of 0.0031, 0.0073, 1.4493, 0.0069 and 0.0016 which indicate dominance of iron rich minerals like limonite, hematite, pyrrhotite and pyrite, and forms lateritic caps on sandstones. Results from SPI estimated depth ranges from 151.6 m (outcropping and shallow magnetic bodies) to 3082.7 m (deep lying magnetic bodies). Depths of shallow magnetic sources resulting from lateritic bodies in the outcrops within the study area as estimated by Euler depths for the four different structural index (SI = 0.5, 1, 2, 3) ranges from 7.99 to 128.93 m. 35 to 150 m depth are good potential water reservoirs for Nsukka and environs. Depths of 1644 to 3082.7 m show sufficiently thick sediments suitable for hydrocarbon accumulation.

Over the years, the people of Akpugo community in Nkanu West L.G.A., Enugu State, South-East Nigeria have suffered from frequent building collapse without knowing the cause. This study integrates geotechnical and geophysical techniques to evaluate possible factors responsible for this anomaly. Areas with cracked and non-cracked buildings were studied to assess the geotechnical properties of the soils. Samples were taken at different locations and subjected to x-ray diffraction analysis, grain size analysis, specific gravity, Atterberg limits, permeability, compaction, and triaxial tests. Electrical resistivity method was also used to delineate the geo-electrical layers and to image the lateral variations of the subsurface. Results revealed that problematic zone (areas with cracked buildings) has lower permeability (4.018-7.016× 10 −7 m/s), lower angle of shearing resistance (10-14°), and medium to high plasticity index (25.1-38.33), while the nonproblematic zone (areas without cracked buildings) has higher permeability (1.55-1.925×10 −6 m/s), higher angle of shearing resistance (15-18°), and low plasticity index (18.1-19.4). The x-ray diffraction results of the problematic zone revealed a significant amount of smectite which has a very high swelling and shrinkage potential. The presence of substantial quantity of smectite in the soils of the problematic zone may be a strong factor in the structural problems. The electrical resistivity profiling delineated the boundary between the problematic zone and non-problematic zone and showed that the problematic zone has lower resistivity values (2-25Ωm) while the nonproblematic zone has higher resistivity values (20-170Ωm).