DEM-based drainage network analysis using steepness and Hack SL indices to identify areas of differential uplift in Emilia-Romagna Apennines, northern Italy

The landscape evolution in active orogens is mainly dictated by the interaction of tectonic and erosional processes. Semi-automated river profile analysis has been performed to investigate the influence of neotectonics on topographic evolution in Emilia–Romagna Apennines, northern Italy. The objective is to use the drainage network from digital elevation model (DEM) to constrain the active structures and prepare the relative uplift rates, steepness and Hack index maps of the region for the first time. Profiles of Secchia, Panaro and Reno rivers and their tributaries were modelled using stream length gradient index and area-slope analysis for concavity, steepness and uplift indices. These proved to be the most useful topographic metrics for recording the effects of local-scale and/or regional-scale active faults. Different zones are distinguished through differential relative uplift. The differences in uplift rates have been found both transverse and parallel to the mountain chain. The highly deformed areas correspond to the presence of active faults. Description of drainage pattern, river profiles, knickpoints, steepness and stream gradient analysis (Hack SL index) are found to be in good agreement with other datasets, signifying that local tectonic deformation of the study area is embedded within a broader, regional uplift of the mountain chain, in association with compressional and extensional structures.