Rapid and non-invasive structural characterization of the Roman Arena in Verona, Italy, through geophysical prospecting

The current Italian guidelines dedicated to monumental assets do not delve into issues related to the characterization of the overall above-soil system and the enhancement of archaeological structures buried below the monumental asset. Furthermore, the guidelines for seismic microzonation focus only on seismotectonic, lithostratigraphic and geotechnical characterization of surface soils, completely neglecting the presence of the built environment. Ground motion and structural response of built environment are treated separately. This aspect can be significantly limiting in historic centres, where heritage buildings rest on numerous subsurface layers of buried structures in an extensively modified subsoil. In this context, the Italian NEW AGE project (PRIN 2022 “NEW integrated approach for seismic protection and valorisation of heritAGE buildings on historical soil deposits”) aims to fill some gaps; during this project, we adopted a multiscale and multi-resolution geophysical approach to investigate geological sub-surfaces, soil/foundations environments and cultural heritage structures and their interactions with each other as a single complex soil-building system by adopting a holistic view. We have tested this approach on two monumental assets of inestimable value, such as the Roman Arena of Verona (Northern Italy) and the Santa Sofia bell tower in Benevento (Southern Italy).

Here we report the first results of MASW, ESAC, of 60 single-station and 9 array seismic prospecting conducted on both the soil and in the Arena. The investigations conducted on the foundation soil and on surrounding the Arena allowed for the mechanical and seismo-stratigraphic characterization of the subsoil, while the surveys carried out within the Arena enabled the estimation of the main structural parameters (vibrational modes, modal shapes, and seismic noise wave propagation velocities) at multiple points of the structure. The main advantages of these surveys are the ease of execution and total non-invasiveness, which makes it possible to characterize even large monumental properties and to carry out the surveys at any time of the day, even during tourist visits.