Channel-profiles metrics in tectonic geomorphology: new insights from a continental piedmont area, a sub-marine canyon system and analogues on Mars

Quantitative geomorphic analysis of landforms has developed and validated many indices that identify the fingerprints of active tectonics on the topography. Specifically, the Steepness Index (Ks), the Stream Length-Gradient Index (SL) and the Distance-Slope (DS) log-log plots of longitudinal profiles are particularly useful in tectonic Geomorphology to delineate catchment morphology and channel-profile anomalies. Numerous tests have demonstrated the validity of channel-profile metrics to detect tectonic-generated knickpoints, especially along trunk valleys. In particular, the Ks index demonstrated to be useful in detecting anomalies in catchment morphology and channel-profiles related to active tectonics in both emerged ranges and sub-marine canyons. Recent outcomes from analogous investigations on Martian surface match the findings from catchments on Earth. Further researches, however, are needed to better understand the sensitivity of the single parameters in detecting tectonic-generated knickpoints in different geodynamic and physiographic settings. Additional investigations are also necessary to verify the validity of the channel metrics regardless of specific typology of flows, for example along debris-flow dominated channels, submarine canyons, and drainage systems on Mars that do not belong to the typical fluvial systems. Accordingly, our research focuses on the calculation and evaluation of Ks, DS, and SL indices, derived from Digital Terrain Models (DTMs), within different test areas from emerged and sub-marine zones on Earth and analogues from Mars. Preliminary results obtained within the Adriatic piedmont area of Apennines (Italy) and a sub-marine canyon system at the Makran margin (Iran), as well as findings from Mars, emphasize the capability of channel-profiles metrics to detect the long-wavelength effects of regional tectonic structures regardless of style and rate of deformation, as well as regardless of processes that act along the present channels.