Seismic loading Engineering characterization of seismic ground motion and key controling factors

This paper presents the main ground motion parameters which are used in earthquake engineering to characterize the seismic loading, as well as the key phyisclal phenomena that control their value and their variability. A first section shortly outlines the principles of strong motion measurement and the main networks and databases. The next section describes in detail the main strong motion parameters that are routinely used in earthquake engineering, i.e., peak time domain values and spectral characterizatons (response spectra and Fourier spectra) together with a few additional quantities originally introduced to improve the correlation with actual damage. The last section outlines the sensitivity of these ground motion parameters to the macroscopic factors used to describe the physics of the source (moment magnitude, stress drop, etc.) and of wave propagation at regional and local scales.