Integration of Geological Surveys and 3D Laser Scanner Techniques in Heritage Sites: How Did Palazzo Belfort Survive the Catastrophic 1618 Piuro Landslide?

The 1618 Piuro landslide (Val Bregaglia, Italy) is known as one of the most catastrophic historical landslides in the Central Alps, which destroyed an ancient village and claimed at least 1000 casualties. The town of Piuro was famous for its opulence and commercial strategic role. Since the half of the twentieth century, the remains of buried buildings were discovered. Among them, the famous Palazzo Belfort survived the landslide although it was partly destroyed by the shock wave. The Belfort buildings were constructed on an ancient alluvial terrace between the trunk river and the northern valley slope, leaned against a boulders deposit. Archaeological excavations revealed some parts of the ancient Piuro town providing hints on the pre-event landscape. By coupling these observations with geological and geomorphological surveys, geomechanical investigations, well-log and geophysical data, a reconstruction of the landslide deposit was obtained. The integrated use of different 3D survey techniques such as Long- and Medium-Range Terrestrial Laser Scanner and Backpack Mobile Mapping System permitted to obtain a multi-resolution Digital Terrain Model of the area, with a resolution of 0.50 m for the Piuro valley floor and of 0.10 m at the Belfort site. Coupling these models with geological analyses, an interpretation of the pre-1618 landscape of the Belfort archaeological area is proposed, to understand the setting of the village and its subsequent evolution. This study developed in the framework of the Interreg V-A IT-CH 2014–2020 Cooperation Program-Axis 2 “Cultural and natural enhancement”. A.M.AL.PI.2018—ID 594,274 with the aim to increase the awareness of natural hazards in mountain settings and to promote a risk and resilience culture.