GNGTS 2019 - Atti del 38° Convegno Nazionale

668 GNGTS 2019 S essione 3.2 nine radargrams were collected using different directions in other key-points. The acquisition parameters of the SEG-Y data included a time window of 100 ns, 1024 samples and a sampling time of 0,098 ns. The data processing, as well as the acquisition, was done using the Prism Software, and included a conventional flow. This flow included: a manual amplitude recovery function; a bandpass filter (100/175/750/1000MHz) to remove low and high frequency noise components; a background removal filter to remove horizontal ringing signals; a time-to-depth conversion done after a velocity analysis that provided an average em velocity value of 11,7 m/ns (ε r = 6,5). Preliminary results are obtained by processing some most representative radargrams chosen within the entire dataset. The processed data allow us to visualize several GPR anomalies in the subsurface close to the Fig. 2 - GPR acquisition and processing information; a) GPR grid used during the data collection at the Piccinino square; b) processed GPR profile displaying numerous diffractions and reflections generated by buried voids. Fig. 3 - Preliminary interpretation results: the map reports the numerous deep GPR anomalies (red) detected along the processed radargrams. The possible tunnel visible within the Estruscan Well (inset image, modified after Stopponi, 1973) doesn’t have a clear GPR signature in the inferred direction. Two possible alternative paths (blue) are currently proposed.