Moreover, a regional geological study focusing on the whole southern Latium territory allowed to make some hypotheses on the origin and availability of the raw materials which were utilized for road construction and maintenance over the centuries.

The geological survey of the Sant'Andrea Valley was led according to lithostratigraphic criteria and with a biostratihraphic characterization of the Cretaceous sequence featuring the carbonate slopes hosting the Appia route track. Several geological formations were identified and complex tectonic and structural settings were acknowledged which largely influenced conditions for the road construction. The geomorphological analysis was focussed on distinguishing between landscape features shaped by geological processes (erosion, gravity-driven events), tectonics and anthropogenic modifications such as quarries, slope cuts or reshaping, terraces (Figs. 1,2).

• Fig.1 Geological survey Fig.1 Geological survey
• Fig.2 Geological survey Fig.2 Geological survey
• Fig.3 Panoramic, lateral view Fig.3 Panoramic, lateral view
• Fig.4 Top view from RPA Fig.4 Top view from RPA
• Fig.5 Evidence of anthropogenic activity Fig.5 Evidence of anthropogenic activity
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A particular attention was dedicated to the geohazard analysis related to active rockfall processes from the steep carbonate cliffs featuring the western edge of the St. Andrea valley. They represent a serious risk for the preservation of the road track and safety of visitors. In collaboration with Nhazca s.r.l enterprise we use modern, integrated, analytical, techniques for the geometric characterization of those rock cliffs identified as possible source areas(Figs. 3,4). Then, after completing a probabilistic modelling of the rockfall process, a plane for hazard mitigation was defined, aimed to the site safeguard.

Local anthropogenic modifications were documented during jointed field surveys with the task group of the University of Campania L. Vanvitelli (Fig. 5), and also characterized in relation with the road construction (iV-III cen. BC) and main maintenance works (XVI and XIX cen AD).

Finally, by combining the analysis of both local and regional (Southern Latium) geological setting, some hypotheses were proposed about the provenance of raw materials.