Deep seated gravitational slope deformation and hydraulic vulnerability of the lower Biferno valley (Southern Italy)

Geological and geomorphological features of the lower Biferno basin are conditioned by deep seated gravitational slope deformation. This is likely to have resulted from the orogenesis of the Apennine ridge on the right side of the valley from “Ponte Liscione” morphological pass to the confluence with Cigno stream. The deformation involved collapse of foredeep deposits at the contact with the allochtonous clay-shales. The paper provides a geomorphological and geological analysis of this deep deformation based on the interpretation of a Digital Elevation Model, illustrated by a geological section. It is shown that Biferno and Cigno catchment morphology and plano-altimetric variation were affected by this phenomenon. In particular, Cigno stream pattern is strongly conditioned by this deep seated movement, which also seems to influence alluvial phenomena and vulnerability landslides in the lower Biferno valley.