A hybrid procedure for the assessment of design basis earthquake ground motions for near-fault conditions

Near-fault ground motions are strongly influenced by the earthquake faultin g mechanism exhibiting distinct long period pulses with amplitudes dependin g on the orientation of the site with respect to the rupture direction. Thi s paper describes a hybrid procedure developed for the assessment of the de sign-basis ground motion for important engineering structures near major fa ults. The procedure relies on the combination of the deterministically obta ined low frequency (DC-1 Hz) ground motion with stochastically simulated hi gh frequency components. A descriptive example, produced as part of a 1997 study of the seismic hazard assessment of a port facility in Izmit Bay area , is provided to illustrate the application of this procedure. The results have been compared with the near-field strong ground motion data obtained d uring the 17 August 1999, Kocaeli, Turkey earthquake (M-w = 7.4), which str uck the very same area where this study had been conducted. (C) 2001 Publis hed by Elsevier Science Ltd.