Morphometric analysis of Sansobbia River Basin (Liguria, Italy) and tectonic Implications

Abstract

The Sansobbia River Basin (Liguria, Italy) is a morpho-structural area of high interest. Through topographic surveys, photo interpretation and quantitative geomorphology techniques, many landscape aspects of the study area have been analysed. The morphometric analysis of the drainage network, showing high values of the bifurcation ratio (4,5 on average) and of the bifurcation index (1,3 on average), demonstrates a strong structural influence on the evolution of the drainage network itself. The drainage network and topographic anomalies highlighted two main morphotectonic directions: E-W and N-S. The same directions were confirmed by the tectonic lineaments derived from aerial photographs and D.T.M. interpretation. Moreover, the azimuth analysis of the ordered Sansobbia network showed E-W and N-S as the most representative directions of the channels. Together with previous geological studies of the region and the new data collected, it is possible to conclude that the two main fracture systems (E-W and N-S) have played, and still play, an active role in influencing the morphology of the whole Sansobbia River Basin.