Shallow Landslides Triggered by the 25 October 2011 Extreme Rainfall in Eastern Liguria (Italy)

Abstract

A very heavy rainstorm hit Eastern Liguria (Vara Valley and Cinque Terre area) and North-western Tuscany (Magra Valley) on 25 October 2011. This event produced floods and hundreds of shallow landslides, causing 13 casualties and severe damage to villages, infrastructures and roads. In the Vara Valley the Brugnato rain gauge recorded 468.8 mm in 6 h, with a maximum rainfall intensity of 143.4 mm/h. A landslide inventory map was carried out, together with a database including the main features of the source areas. At present, the database is complete for the Pogliaschina Torrent basin (Vara Valley), where at least 658 shallow landslides (mainly soil slip-debris flows and debris flows) were triggered. The shallow landslides induced by the 25 October 2011 event were analysed, together with geological, geomorphological and land use features of their source areas, with the aim of identifying common triggering conditions. This paper shows preliminary results of the comparison between the landslide inventory and the main slope features of the Pogliaschina Torrent basin.