Accounting for the uncertainties in the estimation of average shear wave velocity using VS-N correlations

Site-specific seismic hazard analysis is crucial for designing earthquake resistance structures, particularly in seismically active regions. Shear wave velocity ( V S ) is a key parameter in such analysis, although the economy and other factors restrict its direct field measurement in many cases. Various V S -SPT- N correlations are routinely incorporated in seismic hazard analysis to estimate the value of V S . However, many uncertainties question the reliability of these estimated V S values. This paper comes up with a statistical approach to take care of such uncertainties involved in V S calculations. The measured SPT- N values from all the critical boreholes were converted into statistical parameters and passed through various correlations to estimate V S at different depths. The effect of different soil layers in the boreholes on the V S estimation was also taken into account. Further, the average shear wave velocity of the top 30 m soil cover ( V S30 ) is estimated after accounting for various epistemic and aleatoric uncertainties. The scattering nature of the V S values estimated using different V S - N correlations was reduced significantly with the application of the methodology. Study results further clearly demonstrated the potential of the approach to eliminate various uncertainties involved in the estimation of V S30 using general and soil-specific correlations.