Earthquake ground motions are needed to evaluate the seismic performance of new and existing structures and facilities. In seismically active regions the strong ground motion recordings database is usually sufficiently large to physically constrain the earthquake estimation for seismic risk assessment. However, in areas of low seismicity rate, particularly in the Central and Eastern United States, the estimation of strong ground motions for a specified magnitude, distance, and site conditions represents a significant issue. The only available approach for ground motion estimation in this region is numerical simulation.

In this study, earthquake ground motions have been generated for the Upper Mississippi Embayment using a numerical wave propagation formulation. The effects of epistemic and aleatory uncertainties in the earthquake source, path, and site processes, the effect of non-linear soil behavior, and the effects of the geometry of the Embayment have been incorporated. The ground motions are intended to better characterize the seismic hazard in the Upper Mississippi Embayment by representing the amplitude and variability that might be observed in real earthquakes and to provide resources to evaluate the seismic risk in the region.