## 3 Study Area  
The Conero coastal sector stretches for about 5 km along the Adriatic Sea in the Central Italy, 10 km SE of the Ancona city, and represents its inflection point. Mt. Conero (43 deg33'04'' N, 13 deg36'18'' E) constitutes the highest relief along the Adriatic coast with an altitude of 572 m a.s.l. (Figure 1). The climate is of the Mediterranean type with mean annual precipitation of 780-790 mm and mean annual temperature of 14-15 \({}^{\circ}\)C. Summers are generally hot and dry, though a marked variability characterizes winters, mostly depending on the Atlantic cyclogenesis [40]. Prevailing winds approach from the SSE-SSW sectors [30] and account for the dominant SE main wave direction. During the winter months, sea-storm waves up to 3-3.5 m and with NE secondary wave direction can strike the coastline, during Bora wind conditions. The average tidal range in the Conero area is about 0.5 m and the action of tidal current is extremely low [27]. Concerning the geological setting, the Conero promontory consists of an asymmetric, NE-E verging anticline with NNW-SSE axial directions [29; 41] and represents the easternmost outcropping part of the external stack of the Umbria-Marche foreland fold and thrust belt. Limestones and marly calcareous terrains compose the bedrock of the study sector of the Conero promontory and are ascribable to the Umbria-Marche stratigraphic succession, from Cretaceous to Oligocene [29]. The complete stratigraphic sequence consists of the following formations, from oldest to youngest: Maiolica Formation (Fm.) (MA; Lower Cretaceous; prevalently composed of decimetric well-stratified limestones with chert and black shales), Marne a Fucoidi Fm. (MF; Lower Cretaceous; prevalently composed by centimetric marks and marly calcareous layers with black shales), and Scaglia Rossa Fm. (SR; Upper Cretaceous; composed of alternating and well-stratified centimetric to metric limestones, calcarenites, biocalcarenites and marly calcareous layers). In the area, this stratigraphic sequence presents some peculiarities with respect to the outcropping in the internal area of the Apennine chain. In particular, the thickness of the MF is about 15 m, whereas the regional thickness is generally up to 80 m. Furthermore, the paraconformity erosive contact between the MF and SR formations is likely caused by syn-sedimentary slumps [42]; in fact, in the area, the Scaglia Bianca Fm. together with a part of the basal portion of the Scaglia Rossa Fm. is totally absent [27]. The western side of the Mt. Conero anticline is gently dipping (around 25 deg) and affected in the inner part by N-S right-lateral transtensive strike-slip faults with an offset of hundreds of meters. The eastern, coastward flank of the Conero asymmetric anticline is strongly inclined and is intersected by several transversal left-transtensive faults with an average E-W direction and offset a few km (Figure 1). The shear zones are characterized by cataclastic deformation, often with calcite veins and a thickness up to a few meters. The joint pattern is well developed in the rock masses with three prevalent directions NE-SW, NW-SE, and E-W. A pervasive cleavage with subvertical SW dipping planes is observable especially in the Maiolica and in the calcareous Scaglia Rossa bedding. Subhorizontal diagenetic stylolites are quite common in the Maiolica Fm. Subvertical joints are developed mainly in the Scaglia Rossa Fm., with systems striking NW-SE and ENE-WSW, associated with brecias in related shear zones and systematic calcite veins. The morphogenesis along the coastal slope is mainly conditioned by gravity-induced and marine processes, with the corresponding landforms and deposits (Figures 1 and 2). Landslides of different typologies, size, and state of activity are widespread in the area and principally characterize the entire coastal slope morphodynamics (Figure 1). Among the main mass movements, the landslides occurring in the northern coastal sector, at Portonovo and La Vela, are the largest ones (Figures 1 and 3A) [29].