Determination of Basement Depth Using Aeromagnetic SourceParameter Imaging Constraints on The StructuralFramework and its Implications for Geo-Hazard Occurrence in The Upper Benue Trough, NE Nigeria

Abstract

This study investigates the basement depth and structural framework of the Upper Benue Trough, ‎northeastern Nigeria, using high-resolution aeromagnetic data integrated with Source Parameter ‎Imaging (SPI) techniques to assess their implications for geo-hazard occurrence. The aeromagnetic ‎data were processed using Oasis Montaj software 8.9 through standard procedures, including ‎reduction to the equator and regional-residual separation, to enhance subsurface structural features. ‎The SPI method, based on the analytic signal of magnetic sources, was employed to estimate ‎depths to magnetic sources, revealing significant spatial variability ranging from approximately 98 ‎m shallow depths to over 2200 m deeper depths. The results indicate a structurally complex terrain ‎characterized by NE-SW and NW-SE trending fault systems, with deeper sedimentary depocenters ‎concentrated in the central and southern parts of the study area and shallower basement highs along ‎the margins. Integration of SPI-derived depths with lineament density analysis highlights zones of ‎intense fracturing, deformation and structural weakness, which correspond to areas prone to geo-‎hazards such as flooding, subsidence, landslides, and erosion. The findings reveal that basement ‎configuration and fault-controlled structures play a critical role in controlling geo-hazard ‎susceptibility, providing a critical geophysical framework for improved risk assessment, land-use ‎planning, and sustainable infrastructure development in the Upper Benue Trough‎.