Empirical attenuation relationship for Arias Intensity

Arias Intensity is a ground motion parameter that captures the potential destructiveness of an earthquake as the integral of the square of the acceleration-time history. It correlates well with several commonly used demand measures of structural performance, liquefaction, and seismic slope stability. A new empirical relationship is developed to estimate Arias Intensity as a function of magnitude, distance, fault mechanism, and site category based on 1208 recorded ground motion data from 75 earthquakes in active plate-margins. Its functional form is derived from the point-source model, and the coefficients are determined through non-linear regression analyses using a random-effects model. The results show that for large magnitude earthquakes (M > 7) Arias Intensity was significantly overestimated by previous relationships while it was underestimated for smaller magnitude events (M < 6). The average horizontal Arias Intensity is not significantly affected by forward rupture directivity in the near-fault region. The aleatory variability associated with Arias Intensity is larger than that of most other ground motion parameters such as spectral acceleration. However, it may be useful in assessing the potential seismic performance of stiff engineering systems whose response is dominated by the short-period characteristics of ground motions. Copyright (C) 2003 John Wiley Sons, Ltd.