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An investigation was undertaken at St. Agata la Vetere church in Catania, dating back to 333 D.C, in order to obtain essential information for the planned restoration works. In fact, the 1693 earthquake totally destroyed both the church and the adjoining monastery, which when rebuilt changed their original appearance enormously. As a preliminary step, a mineralogic petrographic characterization of the materials was carried out. Optical Microscopy (OM), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Thermo-Gravimetric (TG) analyses were performed on samples of bricks, plasters and mortars. At the same time, ground penetrating radar (GPR) investigations allowed a series of anomalies in the soils to be discovered which can be attributed to the presence of buried structures under the pavement of the church. Lastly, by collecting and collectively interpreting all the results obtained by in situ drillings and tomographic prospections, it was possible to reproduce the substratum behaviour and to localise areas with electric anomalies confirming the existence of hidden structures. [Copyright &y& Elsevier]

Abstract: A geophysical survey was performed at the Roman Amphitheatre of Catania with the aim to study the lithological features of the foundation subsoil of the Amphitheatre and to identify possible underground voids, buried crypts and other heterogeneities. The survey consisted of a number of georadar prospections and of three mechanical drillings. In addition it was experimented a non-invasive technique (passive seismic stratigraphy), which allows to retrieve information on subsoil stratigraphy and on possible seismic site effects. The survey allowed to establish 1) the presence of clays below superficial lava layers in the foundation soil of the Amphitheatre, 2) the presence of 2-D structures below the external ambulatory and 3) the natural resonance frequencies of the structure and of the subsoil in the area of investigation. [Copyright &y& Elsevier]