APPLICATION OF LIDAR-DERIVED DEM FOR DETECTION OF MASS MOVEMENTS ON A LANDSLIDE

Abstract. In order to reliably detect changes in the surficial morphology of a landslide, measurements performed at the different epochs being compared have to comply with certain characteristics such as allowing the reconstruction of the surface from acquired points and a resolution sufficiently high to provide a proper description of details. Terrestrial Laser Scanning survey enables to acquire large amounts of data and therefore potentially allows knowing even small details of a landslide. By appropriate additional field measurements, point clouds can be referenced to a common reference system with high accuracy, so that scans effectively share the same system. In this note we present the monitoring of a large landslide by two surveys carried out two years apart from each other. The adopted reference frame consists of a network of GNSS (Global Navigation Satellite Systems) permanent stations that constitutes a system of controlled stability over time. Knowledge of the shape of the surface comes from the generation of a DEM (Digital Elevation Model). Some algorithms are compared and the analysis is performed by means of the evaluation of some statistical parameters using cross-validation. In general, evaluation of mass displacements occurred between two surveys is possible differencing the corresponding DEMs, but then arises the need to distinguish the different behaviors of the various landslide bodies that could be present among the slope. Here landslide bodies' identification has been carried out considering geomorphological criteria, making also use of DEM derived products, such as contour maps, slope and aspect maps.