GPR and Ultrasonic investigations to study the degradation of the Auriga statue (Mozia island, Sicily)

The archaeological museum of the Giuseppe Whitaker Foundation (Mozia island, Sicily), exhibits the Greek statue of the Auriga, which has been the subject of geophysical investigations to evaluate the degradation of the marble. In particular, a 3D ultrasonic tomography (UST) and some georadar investigations were performed. For the UST 114 measurement points were used, selected on the surface of the statue. The results of the US tomography show an average velocity of the marble equal to about 4700 m/s, which indicates a good mechanical resistance of the marble. There are widespread areas with lower velocity (around 3000 m/s), which however fall within the range of variability of the material. A comparison was made with ultrasound data acquired in January 2012, during a previous diagnostic campaign. Georadar profiles were performed to highlight any internal discontinuity surfaces, which can be interpreted with the presence of fractures and/or lesions. In all the georadar profiles acquired, the internal signal of the material shows a general homogeneity, which allows to exclude the presence of fracturing surfaces and/or internal lesions.