A new reconfigurable stepped frequency GPR system, possibilities and issues; applications to two different Cultural Heritage Resources

This paper describes a geophysical investigation conducted in two important churches, namely the Cathedral of Santa Maria Assunta and the church Santa Croce, both placed in Gravina in Puglia (close to Bari, southern Italy). The church of Santa Croce, now deconsecrated, lies below the Cathedral. Therefore, indeed the two churches constitute a unique building body. Moreover, below the church of Santa Croce there are several crypts, only partially known. The prospecting was performed both with a pulsed commercial GPR system and with a prototypal reconfigurable stepped frequency system. The aim was twofold, namely to achieve some information about the monument and to test the prototypal system. The GPR measurements have been also integrated with an IRT investigation performed on part of the vaulted ceiling of the church of Santa Croce, in order to confirm or deny a possible interpretation of some GPR results.