Implications of surface wave data measurement uncertainty on seismic ground response analysis

Reply on “Implications of surface wave data measurement uncertainty on seismic ground response analysis”

“…Seismic response analyses of these selected profiles are showing considerable variations in the spectral parameters. This clearly illustrates the influence of data measurement uncertainty on seismic ground response analysis justifying the conclusions of Jakka et al [8].…”

“…In our analysis (Fig. 7b, Jakka et al [8]), near about 90% of the selected velocity profiles are having maximum penetration depth only up to 17 m, while halfspace starts after 20 m for profiles little over 4%. More than 96% of profiles' half space starts below 20 m.…”

“…But the profiles are leading to very high variations in the spectral parameters after 1D ground response analysis as shown in our original article (Figs. 17a,b, Jakka et al [8]). So it is very much obvious from these observations that 'the Discussers' claim ('one of our variations in the spectral parameters is mainly because of the consequences of discrepancies in equivalent profiles') does not hold good.…”

“…Selection of equivalent profiles in Jakka et al [8] is based on limiting value of misfit. The limiting value of misfit is calculated from the upper and lower bound curves passing through the extreme points of the standard deviation plot.…”

Characterization of site conditions (soil class, VS30, velocity profiles) for 33 stations from the French permanent accelerometric network (RAP) using surface-wave methods

“…They attribute this to surface wave depth resolution issues, non-uniqueness of the inversion procedures and/or the energy content of the signals used. The consequences of the uncertainties related to nonuniqueness of site responses have been a matter of discussion in recent years Foti et al 2009;Socco et al 2012;Boaga et al 2013;Jakka et al 2014;Comina and Foti 2015;Griffiths et al 2016;Cox and Teague 2016), with some authors claiming that the great uncertainty in Vs profiles leads to high variability of the site responses, although others do not agree. However, considering that the bedrock velocity is well known (e.g., through large arrays or other indirect information) and the velocity profiles are coherent with other indicators (e.g., the ambient vibration H/V frequency peak), the impact of nonuniqueness on site responses remains acceptable.…”