Monitoring and early warning systems: Applications and perspectives

One of the most efficient and cost-effective tools for landslide risk mitigation is often the setup of an early warning system (EWS). Even if the latter encompass both technical-scientific and social-economic topics, the focus of this note is on the monitoring and forecasting components of a slope-scale landslide EWS. In this framework, a landslide monitoring system is required to provide reliable and continuously updated data for quantitatively catching the scenario evolution, thus allowing for correct forecasting analyses and prompt actions for risk mitigation. Landslide monitoring systems based on remote sensing techniques represent efficient and robust tools for risk mitigation, allowing for a low environmental and economic impact and high operator safety in difficult environments. Among these techniques, radar interferometry is one of the most widely adopted and reliable methods, whose advantages include very high accuracy, operation during all weather conditions, and high spatial and temporal coverage. Radar interferometry output data, due to their high accuracy and acquisition frequency (which is getting higher and higher for satellite applications too), perfectly fit in the prediction activity, enabling very often to make accurate and prompt time of failure or scenario evolution forecasts. In this note, a number of case studies are presented, describing the employed monitoring systems and the associated techniques adopted for risk mitigation. In particular, an integrated EWS for rockslide risk mitigation, a landslide EWS in a volcanic environment, a landslide failure prediction using satellite InSAR and a rockfall monitoring and associated time of failure prediction are presented. Each of the cases presented shows a peculiarity that can help in the definition of the characteristics and potential of a modern and reliable landslide EWS, while the recent and upcoming technological and scientific advancements are the premise of even more accurate and meaningful landslide EWSs.