Microtremor measurements interpretations at the BVG station of the Italian accelerometric network

Abstract

In the last decades, researchers focused their attention on using inverse analysis of empirical surface‐waves dispersion curves from microtremor measurements since it allows to keep the cost of investigation relatively low and to avoid the use of active sources that might be prohibitive in urban areas. In this study we reports the results and interpretations of the passive measurements carried out at a test site in Bevagna (Italy) near the BVG station of the Italian Accelerometric Network (RAN) within the framework of the DPC‐INGV S4 Project (2007‐2009). Using two independent approaches, Rayleigh and Love wave dispersion characteristics were reproduced through two different inversion methods. At this site a cross‐hole test made nearby the seismic station offers the opportunity to compare the subsoil velocity profiles derived by seismic noise array data with independent geophysical information. The results obtained from the separated Love waves and Rayleigh wave inversions analyses showed that the two procedure provide consistent shear wave velocity profiles for the shallow part of the model in good agreement with the results of the nearby cross‐hole test. This case history shows the capabilities of surface wave analyses from passive source to adequately retrieve the S‐wave subsoil structure and suggests that more efforts should be devoted in exploiting the potential of coupled analysis of Rayleigh and Love waves from microtremor array measurements for site characterization