Verification of Soil Profiles Obtained from Experimental Rayleigh-wave Dispersion Inversion Using Synthetic Microtremors

An attempt to discuss and/or verify the suitability of subsoil velocity models estimated from Monte-Carlo inversion using synthetic microtremors is performed. In the last 2 decades, experimental Rayleigh dispersion curve from passive microtremor measurements has been explored as a tool for estimating subsoil velocity profiles. The Monte Carlo inversion is one of the most popular methods to estimate them. However, it is also known that the Monte Carlo method gives non-uniqueness solutions. In this paper, the suitability of one of the solutions (the bad case) of soil profiles estimated from experimental surface wave dispersion curves at one site is discussed using the simulation method proposed by the authors in 2009. The simulation is carried out by controlling the magnitude of input sources at the ground surface, through the parameter: ratio of forces RF. As case study, microtremor measurements from an Alpine site are analyzed and compared with the synthetic ones. The synthetic vertical/horizontal dispersion curves and the synthetic classical/modified H/V spectral ratios for certain values of RF are compared with the experimental one. According to this comparison, the tested subsoil profile should be discarded. The proposed method would be a promising tool to resolve the problem of non-uniqueness.