Mountainous regions often experience ground movements that can endanger infrastructure, settlement and the people who live in them. Today, different technologies can monitor these mass movements, in particular landslides, to help make these territories more secure. Each technology has its advantages and drawbacks. The Global Positioning System, or GPS, can monitor the movement of single points on a landslide body. It provides precise measurements with an accuracy to the millimeter. The GPS can measure only single points, however, so it cannot give an overall idea of the landslide's movement. Also, field work to position the GPS antennas is time-consuming and is thus only done once a month. If required it is possible to install permanent GPS stations. The laser scanner generates a 3d digital representation of the landslide by measuring the surface with millions of laser beams. By comparing scans from different moments in time, it is possible to produce differential maps with a resolution of a few centimeters that detect the global movements of an unstable slope. The laser scanner can see through high vegetation, for example trees, but it doesn't work very well in the presence of water or low vegetation, like grassland. In addition, laser scanner surveys can only be done during particular periods of the year because they require intensive site inspections and post-processing. Unmanned aerial vehicles are machines that fly without a human pilot on-board. They can carry different types of sensors, including digital cameras. UAVs can capture images with a spatial resolution of up to a few millimeters. They have the unique ability to access remote and dangerous environments, thus covering surfaces up to several hectares. A UAV flight is nonetheless a complex procedure from a logistical point of view. It requires a flying license and a detailed flight plan, and its success depends on the weather conditions. So flights are usually planned only once or twice a year. Radar satellite systems help monitor landslide displacement by processing satellite data. They send radar images with a spatial resolution of several meters that can cover the entire area of the landslide. In the ideal case, the satellites send the radar images every 6 days. The effectiveness of radar satellite monitoring is hampered if the landslide moves quickly or if it is covered by snow, as its velocity cannot be reliably monitored. As a result of their strengths and weaknesses, these different tools work best if they are combined according to the type of landslides that is to be monitored. Integrating different surveying technologies optimizes their potential. It helps to effectively and sustainably monitor the territory, thus providing important information to local authorities. The characteristics of the monitoring tools, their limitations and the benefits of their integration are the focus of a joint research of Bruno Kessler Foundation, Eurac Research and the Institute of Interdisciplinary Mountain Research of the Austrian Academy of Sciences. The researchers will apply and integrate the surveying technologies in three test areas located in Corvara, Schmirn and Forte Buso. These research studies will take place within the framework of the LEMONADE project.
