Simulation of Near-Fault Ground Motions Using Frequency-Domain Discretization

Methods for stochastic modeling and simulation of ground motions have been of increasing interest in recent years, particularly in connection with performance-based earthquake engineering. Rezaeian and Der Kiureghian (2008) introduced a new fully non-stationary stochastic model for strong ground motions with separable temporal and spectral non-stationarities. The model employs a parameterized stochastic model, which is based on a modulated Gaussian white noise simulated in the time domain. In the first part of this paper, an extension of this model in the frequency domain is formulated. More recently, Dabaghi and Der Kiureghian (2011) developed a stochastic model for simulating near-fault ground motions. The model is based on decomposition of the velocity record into a velocity pulse and a residual motion. The velocity pulse is modeled with a modified version of the Mavroeidis and Papageorgiou (2003) pulse model, while the residual is modeled with the Rezaeian Der Kiureghian approach with a modified modulating function. The present study uses a frequency-domain discretization to describe the velocity pulse as a narrowband process. Thus, it can be considered as a "free-shape" pulse. The residual is simulated with the frequency-domain version of the Rezaeian and Der Kiureghian model. The combined model produces simulations that favorably compare with recorded near-fault ground motions.