Seismic risk evaluation for building portfolio considering amplification characteristics of earthquake ground motion due to subsurface structure

This paper proposes a methodology for seismic risk evaluation of a building portfolio considering the amplification characteristics of earthquake ground motions due to subsurface structure. The main features of the methodology are the following: (1) The response spectrum method is used to calculate the maximum responses of buildings such that the period characteristics of both ground motion and building can be considered for seismic risk evaluation. (2) Considering that the variability of ground motions on the bedrock is not great, a probabilistic response spectral model with spatial correlation on the bedrock of each site is developed such that the amplification of ground motions at each site due to subsurface structure can be reflected into the seismic risk for a building portfolio. This paper also presents a case study for a building portfolio composed of twenty imaginary buildings in Sendai area to verify the features of the methodology.