Near Real Time Monitoring Systems and Periodic Surveys Using a Multi Sensors UAV: The Case of Ponzano Landslide

Abstract

Following the heavy snowfalls in the central and southern Italy at the end of winter 2017, the reactivation of many landslides in the Apennines area was observed. Some of them had already been subject to several seismic events, with main shocks on 08/24/2016 (M6.0) and 10/26/2016 (M5.9). This paper shows preliminary results concerning the Ponzano landslide activity (Civitella del Tronto—Italy), located in the central Italy at about 40 km from the 2016 main earthquakes areas. This landslide reactivated in the last days of February 2017 with displacements of more than 8 meters in the first few days, probably due to the fast snowmelt (about 1.2 m snowpack, accumulated in the middle of January). In accordance with the Department of Civil Protection, different monitoring systems have been foreseen in order to describe the behavior of the landslide and to monitor the oldest part of the village. To reach these goals, a near-real time monitoring approach was implemented by means of a robotized total station. Additionally, a series of UAV aerial surveys for a multi-temporal site analysis were accomplished. The first approach allowed to perform a continuous displacement monitoring (frequency of measurements 0.5 h ÷ 2 h) and to detect landslide movements due to spring rainfalls. The second one allowed us to perform a rapid mapping of the area immediately after the main reactivation, and its evolution after a few months. Thanks to a modular fixed wing multisensor UAV recently developed in our institute, it was possible to perform a survey using optical and multispectral sensors. In this work, we present the results obtained by both systems, and we describe how they can be used in the emergency scenarios and in subsequent landslide management phases.