Ground based remote sensing techniques for the San Leo (northern Italy) rock cliff monitoring

William Frodella (a), Luca Lombardi (a), Massimiliano Nocentini (a) & Giovanni Gigli (a)
(a) Department of Earth Sciences , University of Florence, Via G. La Pira 4, 50121, Firenze, Italy. E-mail: william.frodella@unifi.it

The historic town of San Leo (Emilia Romagna Region, northern Italy) is located on top of an isolated rock massif elevating above the Marecchia river valley hillside. On February 27th 2014 an entire portion of the massif northeastern sector collapsed; minor structural damages were reported in the town and a few buildings were evacuated as a precautionary measure. Minor rock fall events kept taking place on the newly formed rock wall, worsening this hazardous situation. In this framework, a monitoring system based on remote sensing techniques such as ground-based radar interferometry and terrestrial laser scanning was planned, in order to monitor the ground deformation evolution of the investigated area and to evaluate the residual risk. In this paper the main outlines of a one year monitoring activity are described, including a post-event displacement analysis of both the collapse-affected rock wall sector and the rock fall deposits.

Laser Scanning, Radar Interferometry, Rock fall, Marecchia River valley