Integration of the relative active tectonic index and analytic hierarchy process for assessing active deformation in the Bafoussam–Mamfe region (West Cameroon)

Abstract

The relative tectonic activity of the Bafoussam–Mamfe Region (BMR) was assessed using morphometric and geomorphic approaches. Our investigations focused on 117 drainage sub-basins delineated from a 30 m resolution Digital Elevation Model (DEM) through Geographic Information System (GIS)-based techniques. Seven geomorphic indices (Re, Rr, Bs, A _F , TTSF, Vf and HI) were computed to evaluate the influence of tectonic processes on basin morphology. In order to obtain a reliable assessment of relative tectonic activity, two complementary methods, the Index of Relative Active Tectonics (IAT) and the Analytical Hierarchy Process (AHP), were applied. The IAT results indicate four classes of relative tectonic activity (very high: ∼2.56%; high: ∼25.64%; moderate: ∼52.99% and low: ∼18.81%), whereas the AHP approach yields comparable distribution (very high: ∼9.40%; high: ∼38.90%; moderate: ∼35.04% and low: ∼16.66%). Both methods consistently reveal a predominance of moderate-to-high tectonic activity (approximately 81.19% and 83.34% for IAT and AHP, respectively). These results suggest that the morphology of the BMR is strongly controlled by active tectonics, likely driven by lithospheric mantle dynamics and upper crustal deformation associated with the Cameroon Volcanic Line (CVL), as well as the reactivation of inherited Pan-African structures. These processes collectively control the present-day landscape evolution of the region.