1D Vs characterization by Ambient Vibration Array measurement (AVA)

The case study presented in this article demonstrates the effectiveness of the Ambient Vibration Array (AVA) method for characterizing a 1D profile of S-wave velocities (Vs) in near surface. Ambient seismic noise was acquired simultaneously on three circular arrays with diameters of 30, 90, and 270 m, respectively, using 31 three-component nodes. To obtain dispersion curves over the widest possible frequency range, the circles were processed individually. The three-component recording allowed the use of the latest developments of the GEOPSY software, to jointly reconstruct and inverse the dispersion curves of the fundamental and first upper modes of Rayleigh waves and Love waves, as well as the ellipticity of the Rayleigh waves. The resulting 1D model enabled the characterization of Vs down to a depth of 150 m.