The use of multi-copter drones for landslide investigations

In the last couple of years, the combination of the rapid development of low cost Unmanned Aerial Vehicles (UAVs) with improved battery technology and reduction of dimensions and costs of optical sensors has opened the door to a revolution in the geodetic industry. Aero- photogrammetric surveys from high resolution images acquired by light drones flying at very low altitudes (from 50 m to 150 m) are becoming very common. A side benefit for the landslide community is the availability of a new affordable tool to facilitate the acquisition of accurate and detailed morphological data over unstable slopes as a support to geological investigations. In addition to that UAV-based remote sensing has several advantages over the terrestrial surveying, airborne or satellite remote sensing. The most important advantages are represented by the provision of data in near real time, the flexibility in the selection of the most suited sensor, low cost, high resolution and the possibility to get data even in difficult environmental conditions. In this paper, a few case studies on landslide investigations are presented. In these studies the Saturn multi-copter a newly developed tool at the University of Florence, was used to support landslide investigations conducted on different landslides located in Tuscany, Umbria and Sicily areas of Italy. The proposed case studies show how quickly an accurate Digital Terrain Model could be generated by using aerial photographs, acquired with a drone. This technology further aids to perform slope monitoring by comparing multi-temporal acquisitions taken by the drone.