S-waves profiles from noise cross correlation at small scale

Cross correlations of ambient seismic noise recordings are studied to infer shear-wave velocities (VS) profiles versus depth. Experiments are performed, over inter-station distances ranging from 60 m to about 400 m, in the crowded and noisy historical centre of Napoli, where the conditions for the use of active (controlled source) seismic spreadings are prohibitive, even for just one receiver. From the noise cross correlation, group velocity dispersion curves are extracted, with FTAN method, and their non-linear inversion supplies VS profiles versus depth. The information of nearby stratigraphies and the range of VS variability for samples of Neapolitan soils and rocks confirms the validity and reliability of the results obtained with our expeditious procedure. If successfully tested in other geological settings, the proposed approach is a low cost methodology to get reliable VS velocity profiles versus depth.