Soil-building resonance effect in the urban area of Villa d’Agri town (southern Italy)

This study aims to evaluate the possible increase of seismic effects due to the interaction between near surface eology and buildings in the urban area of the Villa d’Agri town (Basilicata, south Italy). 190 single-station seismic ambient noise measurements were performed, 105 on urban soils and 85 on the overlaying buildings. These measurements, analysed based on the Horizontal-to-Vertical Spectral Ratio technique, together with the detailed geological map allowed to reconstruct isofrequency and isoamplitude maps for the whole urban area as well as the relationship between the first vibrational period T(s) and the corresponding height (H) of the measured buildings. Finally, the frequencies of all buildings (659) estimated on the basis of their height have been compared to the frequency of the underlying soil thus enabling us to assess where the soil-building double resonance effect could more likely occur in case of future shaking.