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.

Estimation of the ground motion parameters is extremely important for engineers to make the structures safer and more economical, so it is one of the main issues of Earthquake Engineering. Peak values of the ground motions obtained either from existing records or with the help of attenuation relationships, have been used as a useful parameter to estimate the effect of an earthquake on a specific location. Peak Ground Velocities (PGV) of a ground motion is used extensively in the recent years as a measure of intensity and as the primary source of energy-related analysis of structures. Consequently, PGV values are used to construct emergency response systems like Shake Maps or to determine the deformation demands of structures. Despite the importance of the earthquakes for Turkey, there is a lack of suitable attenuation relationships for velocity developed specifically for the country. The aim of this study is to address this deficiency by developing an attenuation relationship for the Peak Ground Velocities of the chosen database based on the strong ground motion records of Turkey. A database is processed with the established techniques and corrected database for the chosen ground motions is formed. Five different forms of equations that were used in the previous studies are selected to be used as models and by using nonlinear regression analysis, best fitted mathematical relation for attenuation is obtained. The result of this study can be used as an effective tool for seismic hazard assessment studies for Turkey. Besides, being a by-product of this study, a corrected database of strong ground motion recordings of Turkey may prone to be a valuable source for the future researchers.

The purpose of this study is to develop probabilistic hazard maps for EskiSehir including &lsquo / Peak Ground Acceleration&rsquo / values for 10% probability of exceedance in 50-year and 100-year periods at different site classes. A seismotectonic map has been prepared in the Geographical Information Systems environment by compiling instrumental seismicity and neotectonic data for the study area. The seismic sources have been defined spatially in six areal zones, characterized by a commonly used recurrence law and a maximum magnitude value. Four attenuation relationships have been selected being one of them totaly developed from the strong-motion records of Turkey. After the implementation of a seismic hazard model by using SEISRISK software, the probabilistic seismic hazard curves and maps were developed based on the selected attenuation relationships, at &lsquo / rock&rsquo / and &lsquo / soil&rsquo / sites, with a probability of exceedance of 10% in 50-year and 100-year periods. At rock sites the highest levels of hazard were calculated based on the predictive relationship of Abrahamson and Silva (1996), whereas the lowest ones based on the one of Boore et al. (1996). On the other hand the highest hazard levels were determined at soil sites based on the attenuation relationship of Ambraseys et al. (1996), whereas the lowest ones based on the one of Boore et al. (1997). For EskiSehir, the peak ground acceleration values calculated based on attenuation relationship by Boore et al. (1997) were found to be applicable for 10% probability of exceedance in 50 and 100 years, taking into consideration the fact that a considerable portion of the city is founded over alluviums.