Consequences of Solution Non-Uniqueness in Surface Wave Tests for Seismic Response Studies

Surface wave tests are based on the solution of an inverse problem for soil profile identification from the experimentally measured dispersion curve. Most criticism for this testing methodology arises from the non-uniqueness of the solution, i.e. several sets of model parameters can give very similar dispersion curves. In this paper some implications of solution non-uniqueness in seismic response studies are investigated using both synthetic numerical simulations and experimental data. Adopting a Monte Carlo approach for the inverse problem, possible solutions of the inversion process are selected such that they can be considered equally good with respect to the experimental data. This set of soil profiles is subsequently used to evaluate the seismic response of the site. It is shown that equivalent profiles with respect to surface wave testing are equivalent also with respect to site amplification and V_S,30 determination.