This award is for an exploratory study of the feasibility of developing synthetic seismograms which more realistically account for the energy transferred from the ground into a structure, together with a more realistic representation of the structural response. As presently used, synthetic seismograms represent the dynamic structural response as a linear single degree of freedom system. The PI will investigate synthetic seismograms which account for the multi-modal non-linear response of the structure. In addition, these seismograms will encompass the features of an ensemble of real earthquake records which could conceivably be experienced at the site and during the design life of a particular facility.