A model for estimating amplification effects on seismic hazards and scenario ground motions in southern Ontario

Site amplification effects in southern Ontario are highly variable and strongly influence felt effects and damage potential. Site parameters such as shear-wave velocity in the top 30 metres of soil (V-S30), traditionally used to estimate site amplification, are not well known in this region. Thus, regional maps of shaking potential and seismic hazard are often overgeneralized. In this study, a site amplification model based on peak frequency (f(peak)) is compared to one based on V-S30, as given by the 2015 National Building Code of Canada (NBCC). Earthquakes and scenario events are used to estimate ground motions and shaking intensities. It is shown that both models generally predict similar felt intensities but show significant differences in their predicted amplification of ground motions as a function of frequency. The results of this study support the use of f(peak) as a site response variable for estimating amplification effects in southern Ontario.