We discuss a study on the effect of surface wave solution non-uniqueness on 1D seismic site response analysis. The 1D ground response approach used in the considered paper may lead to an overestimation of the variations in amplification spectrum. We also address the numerical simulation of seismic site response. We apply a consistent framework to one real record of the same earthquake to show that, contrary to what is claimed in the considered study, the solution nonuniqueness has negligible effect in amplification and acceleration response spectra.Comment Roy et al. (2013) study the impact of solution non-uniqueness of surface wave inversion on seismic site response of soil column using near-source and far-source earthquake records.They refer to a previous study (Foti et al., 2009) in which it was shown that the impact of solution non-uniqueness on seismic response simulations is negligible for profile having high impedance contrast. They also refer to another study (Boaga et al., 2011) in which it was reported that, in the case of a gradual velocity increase with depth, solution non-uniqueness deeply affects the accuracy of seismic response analyses: for low impedance contrast the effect is much more pronounced than for high impedance contrast, for which the equivalent solutions have a very little influence. The latter was already discussed by Socco et al. (2012), highlighting the importance of a correct procedure in ground response analysis: errors in the selection and application of input motions in seismic response simulation can indeed affect the obtained results.Roy et al. claim that the inversion uncertainty has a pronounced effect on the 1D ground response analysis particularly for the far-field earthquake scenarios: this can mislead the calculations for design ground motions if these uncertainties are not properly addressed.

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