An Investigation into the Morphological Signature of Slow Moving Landslides in the Eastern Apennine Mountains, Italy

This study explores whether slow moving landslides in the Eastern Apennine Mountains of Southern Italy have a unique, morphological signature related to the processes driving landslide motion. We focus on the area surrounding two small hilltop towns, Volturino and Motta Montecorvino. These towns are built on a relatively hard limestone caprock that sits atop highly weathered flysch. Landslides which are formed in the unstable flysch layer, are slowly undermining the limestone caprock. Although hillslope movement is on the order of only centimeters per year, these landslides are compromising the integrity of the infrastructures of these hilltop towns. Using previously made landslide maps and an 8 meter DEM from the Italian government, we delineated the landslides in ArcGIS and extracted morphological data from within and outside of the landslides. Landslide area varies from 2,500m^2 to 310,000m^2, and some landslides have multiple tributary landslides contributing to their total area. Data from the landslides show that slope generally decreases with increasing landslide area. In addition, we find that the landslides tend to have lower slopes and curvature than the surrounding landscape, suggesting that landslide failure leads to reduced hillslope gradients. We explore whether landslides have a preferred aspect, which could indicate that factors such as vegetation and soil moisture, affect landslide formation. Although we do not find that the landslides have a dominant orientation, it does appear that landslide orientation is heavily controlled by geological constraints. We also find that the aspect ratio (ratio of landslide length to landslide width) increases as landslide area increases. In addition, we are examining historical aerial photographs to better understand past landslide events. Finally, we illustrate preliminary observations from ground-based LiDAR collected during our first field season.