## 2 General Setting of the Study Area
### Geomorphological and Engineering-Geological Setting of the Landslide  
The considered landslide affects a SW-facing slope, along which the small hamlet of Fontane is settled (Figure 3). Previous studies described this landslide as an ancient and reactivated complex movement according to the scheme proposed by [PERSON] and [PERSON] [63], albeit a dominant rotational sliding component has been supposed [61]. The landslide, which extends between 360 and 95 m a.s.l. with a length of approximately 650 m and a maximum width of approximately 250 m, can be separated into two main zones (Figure 3). The upslope part encompasses both the main landslide crown and scrap along with an upper portion of the principal head. The main crown develops along the southern side of the M. Castello ridge. Below it, a mostly emptied sector, with a general concave shape and an average steepness of 25\({}^{\circ}\), occurs (Figure 3). This sector is characterized by sporadic rock outcrops alternating with remoulded landslide debris and it is almost completely terraced for agricultural activities. Figure 2: Geologic setting of the study area: (**a**) tectonic sketch map (redrawn and modified from [56]: (1) Lavagna Unit, (2) Gottero Unit, (3) Bracco-Val Graveglia Unit, (4) fault, (5) thrust, (6) axial plane trace of anticlinal, (7) axial plane trace of synclimal; (**b**) geological map (the black dashed line indicates the trace of the geological cross section): (1) landslide deposit, (2) slope deposit, (3) alluvial and marine deposit, (4) Giaiette Shales Fm., (5) Gottero Sandstones Fm., (6) Forcella Banded Shales Fm., (7) Cogorno Sandstones Fm. (8) Palombini Shales Fm., (9) Case Boeno Breccias Fm., (10) basalts, (11) serpentinites, (12) thrust, (13) tectonic contact, (14) fault, (15) hydrographic network; (**c**) geological cross-section: (1) Giaiette Shales Fm., (2) Gottero Sandstones Fm., (3) Forcella Banded Shales Fm., (4) basalts (redrawn from [58]). Since neither historical information nor significant geomorphological indicators of movement are known or visible, this zone is considered inactive. In this work, only the downslope part of the landslide has been taken into consideration, since it is characterized by active kinematics. Based on previous information from [55; 61] and local inhabitants, abrupt accelerations, interspersed with active or dormant phases, are known to have occurred from this sector of the landslide in the last sixty years. The two most important reactivations date back to 1957-1958 and 2014. The active portion of the landslide, which basically includes the displaced material, has an extension of about 5.5 hectares, developing from approximately 220 m a.s.l. up to 95 m a.s.l., with an average slope gradient of 20\({}^{\circ}\) (Figure 3). Laterally, it is bordered by the flanks of two secondary ridges, approximately NE-SW oriented, while the toe is currently eroded by the Staffora stream. Moreover, this part of the landslide is incised by two short and linear streams. Its geomorphological layout is somewhat irregular owing to the progressive effects of principal and minor mass movements, subaerial erosion processes, and human activity. The morphology is thus uneven, showing zones of depletion alternating with bulging areas (Figure 3). [PERSON] et al. [55] outlined the main geometrical characteristics of the accumulation zone through combined analysis of data collected from stratigraphic boreholes and seismic refraction surveys deployed by local authorities and private owners at different times between 2008 and 2016 (Figure 4). Figure 3: Shaded relief map of the Fontane di San Bernardo site: (1) inclinometer; (2) piezometer; (3) stratigraphic borehole; (4) geophysical survey; (5) rain gauge; (6) dormant crown; (7) active tension crack; (8) engineering–geological cross-section profile. Based on such study, engineering-geological cross-sections in the longitudinal and transverse directions were developed, showing that the thickness of the landslide deposit is extremely spatially variable.