Structural and geomorphological constraints on active normal faulting and landscape evolution in Calabria, Italy

Calabria is one of the fastest-uplifting and most seismically active regions in the Mediterranean, yet the time-averaged (c. 10⁶ years) rates of normal faulting remain poorly constrained. Here, we use digital elevation model analysis, geological cross-sections and a compilation of published data to quantify systematically along-strike the fault throws and time-averaged throw rates of the Serre, Cittanova, Armo, East Crati and West Crati faults. We show that regional uplift has uplifted both their hanging-wall and footwall blocks by c. 200-400 m, and the Aspromonte massif by up to c. 1150-1300 m. We find that these faults have throws between c. 640 and 1430 m, and throw rates between c. 0.6 and 1.4 mm a^-1. Their footwall ranges have variable proportions of inherited relief, up to c. 300-800 m. The channels draining these ranges reflect the active normal faulting and relief in their steepness indices, becoming c. 5-8 m^0.9 steeper for each 0.1 mm a^-1 throw rate increment and each 100 m relief increase. Finally, the presence of knickpoints suggests that these channels are transiently responding to changes in relative base-level, which could be due to fault linkage or regional strain rate increases for the southern Calabrian faults, and to regional uplift acceleration in the case of the Crati faults.