GB-InSAR monitoring of slope deformations in a mountainous area affected by debris flow events

Abstract. Diffuse and severe slope instabilities affected the whole Veneto region (north-eastern Italy) between 31 October and 2 November 2010, following a period of heavy and persistent rainfall. In this context, on 4 November 2010 a large detrital mass detached from the cover of the Mt. Rotolon deep-seated gravitational slope deformation (DSGSD), located in the upper Agno River valley, channelizing within the Rotolon Creek riverbed and evolving into a highly mobile debris flow. The latter phenomena damaged many hydraulic works, also threatening bridges, local roads, and the residents of the Maltaure, Turcati, and Parlati villages located along the creek banks and the town of Recoaro Terme. From the beginning of the emergency phase, the civil protection system was activated, involving the National Civil Protection Department, Veneto Region, and local administrations' personnel and technicians, as well as scientific institutions. On 8 December 2010 a local-scale monitoring system, based on a ground-based interferometric synthetic aperture radar (GB-InSAR), was implemented in order to evaluate the slope deformation pattern evolution in correspondence of the debris flow detachment sector, with the final aim of assessing the landslide residual risk and managing the emergency phase. This paper describes the results of a 2-year GB-InSAR monitoring campaign (December 2010–December 2012) and its application for monitoring, mapping, and emergency management activities in order to provide a rapid and easy communication of the results to the involved technicians and civil protection personnel, for a better understanding of the landslide phenomena and the decision-making process in a critical landslide scenario.