Ground-motion determination for analysis and design of engineering structures is a shared, interdisciplinary task involving geologists, seismologists, geophysicists, geotechnical engineers, and earthquake engineers. Considerations in developing ground motions representing all of these disciplines are presented beginning with a current assessment of geologic and seismic hazard on an overall or regional scale and continuing with discussions on; local site effects measurement of strong ground motion, seismologic characterization of ground motion, determination of laboratory and in-situ properties to enhance analysis of ground-motion transmission, practical development of ground motion for structural analysis, and ending with an analysis of the effects of strong ground motion and large deformation.