Seismic Characterisation of a Site in the Alps

This study concerns the dynamic characterisation devoted to seismic response analysis of an Alpine test site. We show how integration and combination of different seismic techniques allow a comprehensive characterisation of the site leading to a reliable 2D model for site amplification studies. For the evaluation of the deep structure and the location of the seismic bedrock, combined seismic reflection-refraction tests are used while the shear wave velocity profile is obtained by down-hole measurements and surface wave tests, performed integrating passive and active data to increase the depth of penetration without loosing in resolution of shallow layers. The ground roll affecting reflection-refraction seismic data is also used to reconstruct lateral variation of the shear wave velocity in the soil deposit by means of an innovative inversion approach based on the integration of Monte Carlo and Laterally Constrained Inversion, in which the Vs profiles obtained from the others seismic techniques are used as constrains to improve the reliability of the final solution. Moreover an estimation of the quality factor (Q) is performed from records acquired for surface wave analysis. The use of the same seismic records for different and independent analysis optimize the cost effectiveness of the whole survey.