9870509 Zerva A POWRE award will support for one year the conduct of research by PI at California Institute of Technology, where she will collaborate with Prof. J.L. Beck. The joint study will combine the PI's expertise in identifying the causes of spatial variability in seismic ground motions with Dr. Beck's expertise in statistical system identification. The spatial variation of ground motions may affect the response of lifelines, such as bridges and pipelines, beyond the loads expected from uniform motions. Existing models are based, generally, on regression analyses of data recorded at a single site and for a single event. Thus, they cannot readily be applied to different sites and events, which limits their usefulness. In order to overcome this limitation the present study will incorporate physical parameters in the spatial variability model, parameters which are estimated, where necessary, using system identification. The approach will embed the system identification scheme in a statistical frame work, that accounts for uncertainties in the model parameters and in the predictions from the model itself. A Bayesian scheme will be used, allowing the predictive probabilities to be updated with additional information from various sites and events, until the models stabilize or converge. The project will enhance the PI's career by broadening her research horizons, specifically in the areas of statistical system identification, reliability-based optimal design and robust structural control. She expects to apply this knowledge in future research related to the safety and reliability of the older and decaying infrastructure of the East Coast, where her home institution is located. ***
