Alternative Hybrid Empirical Ground Motion Model for Central and Eastern North America Using Hybrid Simulations and NGA West2 Models
Abstract An alternative hybrid empirical ground motion model for central and eastern North America (CENA) is proposed. The new ground motion model (GMM) is developed for the average horizontal components (RotD50) of peak ground acceleration, peak ground velocity, and 5% damped pseudospectral accelerations at 0.01 10 s spectral periods. Hybrid empirical estimates are derived using the regional modification factors between two regions (host and target) along with empirical GMMs from the host region. The regional adjustment factors are ratios of the intensity measures from the generated synthetics in the host (western North America [WNA] and target (CENA) regions. In this study, the recent updated empirical GMMs developed by the Pacific Earthquake Engineering Research Center for the Next Generation Attenuation West2 (NGA West2) project (Bozorgnia et al. 2014) are incorporated. We used a broadband simulation technique proposed by the authors (Shahjouei and Pezeshk, 2015a) to generate synthetics for both the WNA and CENA regions in which the high frequency and low frequency parts of synthetics are calculated through a stochastic finite fault method and kinematic source models along with the deterministic wave propagation, respectively. The updated seismological and geological parameters are deployed in simulations. The new ground motion model is developed, as part of the NGA East research project, considering multiple shaking scenarios that characterize the magnitude in the M 5.0 8.0 range. The proposed GMM represents the level of ground shaking in the distance range of 2 1000 km and are developed for the reference rock site condition with V S 30 =3 km/s in CENA. The results are compared with some other existing models in the region. In addition, a comprehensive residual analysis is performed using the recorded earthquakes available in the NGA East database.