Modeling Pre-Anthropogenic Topography: A Reconstruction in the Perugia Center Using Subsoil Data

This study aimed at developing a digital elevation model of the city center of Perugia, the capital city of Umbria region (Central Italy), to approximate the terrain as it existed prior to human settlement, and study the anthropogenic deposits identified in different locations of the study area. In fact, the foundation of the city dates back 3000 years, and human modifications played a key role in shaping the area. Main modifications exist in the city center area, located on a series of hilltops. Data about the thickness of anthropogenic deposits, from approximately 200 boreholes, allowed us to reconstruct the pre-settlement topography. Numerical interpolation of data about thickness of deposits revealed key areas with significant modifications, mostly located close the watersheds’ drainage divide, where the fluvial and gravitational erosional processes acted in the past. In contrast, other areas close to the top of the hill displayed evidence of artificial leveling. This research enhances the geomorphological mapping of Perugia by precisely delineating the extent and thickness of anthropogenic deposits and allows to recognize and perimeter inactive landforms, currently invisible on the topographic surface. Knowledge of the pre-settlement topography provides critical insights into the historical evolution of the landscape and offers valuable support for urban planning and stability assessments. The methodology holds promise for application in similar urban contexts across Umbria and beyond.