UCLA Civil and Environmental Engineering

Results of 1D ground response analyses are typically not incorporated into probabilistic seismic hazard analyses (PSHA) in a statistically robust way. Often ground response is incorporated into PSHA using deterministic amplification factors. This simplistic method generates results that are intrinsically arbitrary and often unconservative. The main problem in probabilistically linking PSHA and ground response lies in quantifying the dispersion that is appropriate for use with ground response analysis results. We review two alternative procedures for quantifying this uncertainty and illustrate their differences with respect to dispersion values of spectral acceleration at the surface for various site conditions.