Appraisal and safe fruition of an important geosite in the Northern Apennines: the Pietra di Bismantova cliff (Reggio Emilia province, Italy)

Among the geosites of regional and national importance in the Emilia Apennines, particular relevance is attributed to the Pietra di Bismantova cliff (1046 m a.s.l.). From a morpho-structural standpoint, the Pietra di Bismantova is an example of mesa, whose summit corresponds to a lithologic-structural surface, which developed in morphoclimatic conditions different from the present ones. The area surrounding the Pietra di Bismantova has been affected by considerable climatic changes since the end of the last glaciation to date, eventually leading to the development of vast landslides. This cliff is made up of a stratified calcareous rock type rich in mollusks and other fossilized remains typical of a tropical climate and overlies marly and clayey formations. Owing to its perpendicular rock faces, the Pietra di Bismantova has always attracted numerous rock climbers and hikers who, since the early 20th century, have opened many climbing ways and trails still in use today. Furthermore, its sheer calcareous slopes are favored sites for the nesting of rare birds, among which some species of raptors.Owing to all these characteristics, the Pietra di Bismantova is of geologic-geomorphologic, environmental, cultural and recreational interest. The appraisal of this important geosite and its geodiversity, however, must take into account the inevitably high human impact which on the one hand might accelerate the degradational processes affecting it and, on the other hand, pose serious risks for the safety of visitors. The area surrounding the cliff is, in fact, affected by various kinds of landslides. The goal of this research has been to identify the areas most prone to geomorphologic hazards and possible risk situations for the numerous tourists visiting this geosite. Investigations have been carried out by means of detailed geomorphologic observations and surveys aimed at the geomechanic characterization of the rock types making up the Bismantova cliff. The results have shown that the areas potentially most subject to landslides are the NE and the southern sectors, where safety measures should be introduced to guarantee safe fruition to all visitors.