Collaborative geoscience investigations in natural and archaeological heritage sites: the Palazzo Belfort area of Piuro (SO, Italy) case study

The 1618 Piuro landslide is known as one of the most catastrophic historical landslides in the Central Alps, as it caused the destruction of the ancient village and at least 1000 casualties. Piuro is situated in the Italian Bregaglia Valley, and at that time was famous for its opulence, partly derived from the extraction and trade of soapstone. The presence of many stately buildings in the area before 1618 is testified by iconographies and documents. Since the ‘60s the remains of some of these buildings, buried or destroyed by the 1618 event, were discovered. Palazzo Belfort survived the landslide although partly destroyed by the shock wave and now in ruins. The buildings of the Belfort area were constructed between the trunk river and the northern slope of the valley, leaned against a metric to decametric boulders deposit and on an ancient alluvial terrace. These characteristics help to reconstruct the pre-1618 village and offer clues on the geomorphological evolution of the area. Moreover, the discovery of a chunk of a soapstone aqueduct below the 1618 landslide deposits (Breda et al., 2014) gave us a hint on the appearance of Piuro within the pre-landslide landscape. 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 valley bottom of Piuro and of 0.10 m for the Belfort site (Marotta et al., 2021). Coupling these models with geological analyses that permitted to outline the extent of the 1618 landslide deposits and to describe the shallow Quaternary stratigraphy of the valley (Pigazzi et al., 2022), we propose an interpretation of the pre-1618 landscape of this area to an archaeological scale, useful to understand the setting of the village and its subsequent evolution. The result of this study is a 3D high-res model of the site constrained by archaeological, morphological and geological data and observations, which proves useful for geomorphological analyses on a scale required for archaeological reconstruction, but also in terms of geo-touristic and cultural fruition of the area within the Interreg project A.M.AL.PI.18 (Interreg V-A IT-CH 2014-2020 Cooperation Program – Axis 2 “Cultural and natural enhancement”, Id 594274 - A.M.AL.PI.18 “Alpi in Movimento, Movimento nelle Alpi. Piuro 1618-2018”).