Applicability of Site Amplification Models for Hard Rock Site Conditions

Site effects are typically modeled with a single parameter, the shear wave velocity at the uppermost 30 m (VS30), representing the soil profile's overall seismic response. VS30-based site amplification models may be used as standalone tools to determine the site amplification factors or implemented in ground motion models for various soil conditions. Nevertheless, the accuracy of the empirical site amplification models for stiff soil and rock sites is debatable due to a limited number of empirical recordings from stiff site conditions. This study aims to test the applicability of recent site amplification models with the amplification factors estimated from selected strong ground motion stations of the Turkish Disaster and Emergency Management Presidency, AFAD. To calculate the site amplification factors, recorded ground motions at the surface were deconvolved to deeper and stiffer soil layers by one-dimensional equivalent-linear response analysis. Estimated site amplification factors are compared with the recent site-amplification model proposed by Stewart et al. and Hashash et al.. Analysis results showed that the estimated amplification factors are generally in good agreement with the models in terms of amplitude. Still, significant differences are observed in the peaks of the amplification factors concerning frequency.