Endangered historic sites: the case study of Santa Croce in Ravenna (Italy)

The city of Ravenna (Italy) is worldwide famous for the well-preserved late Roman and Byzantine architecture with eight buildings protected by UNESCO as part of the World Heritage Site “Early Christian Monuments of Ravenna”. Climate change effects have increased the site vulnerability to natural hazards, in particular flooding and subsidence, two phenomena often strictly interrelated. The topic has been addressed with reference to the complex of Santa Croce in Ravenna (Italy), an emblematic case of the main hydrogeological and water-related threats affecting the city monuments. A recent geotechnical campaign and a new piezometric monitoring system helped to gain information on the local subsoil and on the drainage system, permanently operating in the area in order to maintain it dry; the 3D geometry of the complex was obtained by integrated geomatic techniques (mainly laser scanning and photogrammetry). The paper aims at presenting the main geotechnical issues affecting the site stability and its long-term preservation