Geophysical surveys for the dynamic characterization of a cultural heritage building and its subsoil: The S. Michele Arcangelo Church (Acireale, eastern Sicily)

Geophysical surveys are useful tools to characterize the buildings making up the cultural heritage and to monitor the subsoil features on which they are constructed. The information obtained is necessary for planning future restoration work. The aim of this study is to characterize the dynamic features of both the San Michele Arcangelo Church and of the area where it is located. Non-invasive geophysical surveys, including electromagnetic and seismic surveys, were performed to acquire this information. Such techniques enabled us to highlight the seismic wave velocity distribution in the subsoil, and the presence of electromagnetic reflectors probably linked to the existence of remains belonging to the old edifice. The comparison and integration of different methods allowed us to validate the results. Moreover, ambient seismic noise measurements were carried out outside and inside the church to obtain information on the site resonance frequency and to assess the vibration frequencies of the church. The results do not point out any site amplifications in the vibration frequency range of the church. It is therefore unlikely that soil-to-structure resonance phenomena can take place.