River dynamics and slope processes along a sector of the Villalvernia-Varzi line (Northern Italy)

he river dynamics and the slope processes along a sector of a regional tectonic line, the Villalvernia-Varzi Line, in the Northwestern Apennines (Northern Italy), were investigated. This line has been referred to as a dextral transpressive system and has played an important, but not yet well-defined, role in the structural context of the Apennines. The Staffora River basin is characterised by a complex geological and structural setting of the outcropping soils, consisting in sedimentary formations with a dominant clay component. The planimetric and altimetrical characteristics and long-term evolution of the riverbed were studied. Analysis of the thickness of the alluvial sediments allows division of the Staffora River into two blocks: the northern block with the minimum alluvial sediment thickness and the southern block with the highest values of thickness. Different factors could be responsible for this peculiarity, including contribution of the tributaries, presence of landslides and alluvial fans, human intervention, and tectonics. The occurrence and distribution of the landslides with various influencing factors were analysed in order to verify the tectonics as factor of the slope movements and whose landslide characteristics could be related to it. (C) 2002 Elsevier Science Ltd and INQUA. All rights reserved.