Slope instability induced by climate changes on the UNESCO Etruscan necropolis of Monterozzi (Tarquinia, Italy)

The Necropolis of Monterozzi (Tarquinia, Central Italy), with hundreds of painted rock cut tombs of VII-II centuries B.C., is a unique evidence of the Etruscan vanished culture. During year 2017, in the northern side of the necropolis, near the edge of the hill where the site stands, several tombs began to be affected by wall cracks. After the request of intervention from the local Soprintendenza, ISPRA (Geological Survey of Italy Dept.) and University of Bologna (DICAM) started to analyse the stability of the most threaten tombs. First step was the understanding of the climatic, geologic, geomorphologic and geotechnical setting, to verify the overall stability conditions and the landslide hazard possibly induced by climate changes. In fact, year 2017 registered minimum rainfall of last 40 years and high temperatures. Some tombs were equipped with a crack gauge system to monitor the deformation pattern. The biogenic calcarenite (Macco formation) in which the tombs are carved out was tested in the laboratory to define its physical–mechanical properties. Finally, a 3D model was generated from a detail topographic survey, combined with more precise surveys (Terrestrial Laser Scan and UAV modelling), to carry out stability analysis of both slope and tombs. The study achieved the preliminary identification of low impact mitigation and conservation measures for the safeguard of the site against climate changes related slope instability.