Definitions of duration are reviewed, with emphasis on the one, which is used in most studies. In this definition, the duration is related to the rate of energy input into structures. Next, the physical parameters of the earthquake source and propagation path, and regional geologic and local soil characteristics, are discussed, as those influence the duration of strong motion. Finally, scaling models are illustrated, obtained from regression analyses of strong motion recordings in the western USA.
Keywords: Duration, Energy, Rupture, Path and Regional Effects