Can Drones Map Earth Cracks? Landslide Measurements in North Greece Using UAV Photogrammetry for Nature-Based Solutions

The accuracy of photogrammetry for geohazards monitoring has improved within the last years because of the "drone revolution". This study is an attempt to perform morphometric measurements in a landslide event that took place near the village Nea Zichni in Northern Greece. The DJI Mavic 2 Pro was selected to capture orthoimages of the entire area including the landslide event but also other adjusted disaster phenomena. The images were loaded in the commercial software Pix4D in order to produce orthomosaics and digital surface models of the area. The georeferenced results were further analyzed in ArcGIS in order to digitize and estimate the morphometric parameters of the landslide, such as its area and volume, but also to detect cracks and plot the tensile cracking directions. We conclude that the methodology and produced outputs are crucial for the responsible authorities to detect, monitor and mitigate natural disasters such as landslide events and other mass movements. The best practices to control mass movements are nature-based solutions such as soil bioengineering and proper vegetation cover assisted by engineering measures. Finally, our goal is to frequently monitor the landslide phenomenon in order to determine its evolution.