Geophysical surveying of the ancient walls of the town of Cagliari, Italy, by means of refraction and up‐hole seismic tomography techniques

The ancient walls of Santa Croce in the town of Cagliari (Sardinia, Italy), date back to the Middle Age and have had, until the nineteenth century, several interventions with superpositions and modifications. Beyond the historical and archaeological interest, the study of the structure of the ancient walls became necessary in view of building an underground car parking just at the base of the walls itself. With this purpose, in addition to classical archaeological surveys a geophysical non‐destructive survey with seismic techniques has been carried out, namely two refraction tomographies aimed at characterizing the rocks at the base of the walls, and four up‐hole tomographies across the walls itself. These geophysical surveys provide good geotechnical information on the foundation condition, the problematic feasibility of the underground parking and, along with the archaeological procedures, on the heterogeneous structure of the walls.