Active tectonic assessment of the SW Cameroon Atlantic Coast using morphometric and geomorphic approaches

We use morphometric and geomorphic approaches in order to evaluate the relative active tectonic index (IAT) of the SW Cameroon Atlantic Coast, including the active Cameroon Volcanic Line (CVL). We determine the linear, areal, relief morphometric parameters and geomorphic indices of 53 drainage basins from the Digital Elevation Model (DEM, 30 m) using Geographic Information System (GIS) interpretive techniques coupled with available geological and field data. The results of the landscape analysis reveal significant variations of the morphometric parameters and geomorphic indices within the study area. The linear (~ 67.92%), areal (~ 94.34%), and relief (~ 86.84%) morphometric parameters, as well as the geomorphic indices (~ 84.91%), indicate a strong structural control. The longitudinal river and normalized stream profiles display complex, stepped, and uneven shapes with knickpoints (Kps). These results highlight the dominance of the tectonic control over the lithological variations and differential erosion. From the IAT values, the area is subdivided into very high (~ 18.87%), high (~ 54.72%), moderate (~ 22.64%), and low (~ 3.77%) tectonic classes. The high-to-very high tectonic activity (~ 73.59%) proves that the SW Cameroon Atlantic Coast is tectonically unstable due to mantle dynamism, CVL activity, and differential erosion.