Monitoring of anthropogenic landslide activity with combined UAV and LiDAR-derived DEMs: a case study of the Czerwony Wawoz landslide (SW Poland. Western sudetes)

The paper presents the results of fieldwork and geodetic surveys carried out on a landslide in Wleń (Western Sudetes, Izerskie Foothills). This reactivated landslide occured firstly in 2011 and later on 16th July 2016, following heavy rainfall in the Lower Silesia region, and covered an area of ca. 1100 m2 above the renovated “Leśny Dwór” guesthouse in Wleń town. The main scarp of the landslide is built of strongly deformed Upper Permian (Zechstein) heterolithic deposits, composing the marginal part of the Wleń Graben - a NW-SE elongated, tectonic sub-unit within the North Sudetic Synclinorium. The landslide was a consequence of undercutting of steep slopes of the Bóbr River valley by anthropogenic activities and loading of the slope surface by blocks and pedestrian paths in the vicinity of the guesthouse. Monitoring of landslide activity was performed using the initial surface model of the slope subjected to mass movements, LiDAR elevation data, as well as 3D point cloud data from a non-metric camera on an Unmanned Aerial Vehicle (UAV). They were used to construct digital elevation models (DEMs) of the area covered by the landslide. The DEM from photogrammetric UAV data was processed using Structure from Motion (SfM) technology. The obtained dataset was verified by additional measurement series from terrestrial laser scanning (TLS).