Characteristics of Simulated and Recorded Ground Motions for Bucharest

Abstract

A dataset consisting of more than 400 ground motions recorded during Vrancea intermediate-depth earthquakes that occurred in the period 1977–2013 was compiled in the BIGSEES project financed by the Romanian National Authority for Scientific Research. The analysis of the frequency characteristics of the existing ground motions recorded in the Bucharest area shows that the long-period spectral ordinates increase with the level of the peak ground acceleration, thus denoting possible nonlinear soil effects. The analyses also reveal the fact that the spectral displacement demands imposed by the ground motion recorded during the Vrancea 1977 earthquake at INCERC station shows much larger values as compared to the spectral displacement demands imposed by the ground motions recorded in the Santiago (Chile) area during the Maule 2010 earthquake or in the Wellington (New Zealand) area during the Kaikoura 2016 seismic event. The predictive models proposed for the control periods T C and T D highlight the fact that the values of the two periods increase with the earthquake magnitude, while the maximum ratio between spectral acceleration SA and peak ground acceleration PGA decreases with the earthquake magnitude.