Impact of site classification on deriving empirical ground-motion prediction equations : application to the West Eurasia dataset
Congress title :AFPS'07 7ème Colloque National
Congress town :Châtenay-Malabry
Congress date :04/07/2007
We classify sites based on theirpredominantperiod computed using average horizontal-to-vertical (H/V) response spectral ratios and examine the impact of this classification scheme on empirical ground-motion models. We apply this classification scheme to the database of Fukushima et al. (2003), for which stations were originally classified as simply rock or soil. The calculation of average H/V response spectral ratios permits the majority of sites in the database to be unambiguously classified. Soft soil conditions are clearly apparent using this technique. Ground-motion prediction equations are then computed using this alternative classification scheme. The aleatoric variability of these equations (measured by their standard deviations) is slightly lower than those derived using only soil and rock classes. However, perhaps more importantly, predicted response spectra are radically different to those predicted using the soil/rock classification. In addition, since the H/V response spectral ratios were used to classify stations the predicted spectra for different sites show clear separation.