Investigation on site-specific seismic response analysis for Bucharest (Romania)

Abstract

In this study, the nonlinear seismic response analysis of five sites with deep boreholes in Bucharest (Romania) is performed. A ground motion database consisting of recordings obtained during several Vrancea intermediate-depth earthquakes is compiled for the analyses. The results of the nonlinear site response analysis show that significant long-period spectral amplifications occur for all five sites and that the level on input peak ground acceleration influences in a significant manner the spectral amplifications, both as median value and variability. In addition, the differences in terms of site amplification factors between the five analysed sites also increase with the level of the input peak ground acceleration levels. The median site amplifications decrease with the increase of the peak ground acceleration for spectral periods of up to 2.0 s, while for longer periods the median site amplifications increase. The results of the nonlinear site response analysis were also validated by using real ground motions recorded in the same area during recent Vrancea intermediate-depth earthquakes.