Studio geologico del fenomeno gravitativo di Albugnano (Collina di Torino, Piemonte)

Geological analysis of the Albugnano landslide (Collina di Torino, Piemonte, NW-Italy)

Abstract

Several mass movements and relative landforms and deposits have been recently singled out on the hills of Piemonte; chosen among these phenomena, here it is considered a slide mass extending to the SW of Albugnano. The landslide deposits cover an area of about 1 km², with an approximate thickness of some tens of metres; the head scarp is 800 m-long, partially affecting Albugnano village. Morphological and sedi-mentological features are described in detail. Meso-structural data from both pre-Quaternary and Quaternary formations outcropping in the surrounding area are presented. Landslide relationships with fluvial deposits and paleodrainage features of Pleistocene age suggest us to ascribe it to a generic Holocene age; the considerable dissection of the slide mass allows us to exclude a very recent age of formation. The proximity of the Albugnano landslide to the Rio Freddo Deformation Zone (superficial expression of a crustal discontinuity between Torino Hill and Monferrato), the local occurrence of several structural discontinuities and the coincidence of hilly area to one of the sectors of highest historical uplifting rate of Northern Italy allow us to suppose a connection of the landslide phenomena also to the recent geodinamic evolution, at least as predisposition to landsliding. Instability phenomena of the frontal area of the landslide mass, affecting buildings of Mistrassi area, are also described. New constructions in the Albugnano village, at the landslide head-scarp, could compromise slope stability, causing local reactivation of the mass movement.