Correlation of Significant Duration with Amplitude and Cumulative Intensity Measures and Its Use in Ground Motion Selection

Abstract

This manuscript examines, and develops parametric equations for, the correlation of significant duration with several amplitude- and cumulative-based ground motion intensity measures. The correlations are determined using ground motions from active shallow crustal earthquakes in the Next Generation Attenuation database, and recently developed ground motion prediction equations. It is found that significant durations tend to be negatively correlated with high-frequency amplitude-based intensity measures, weakly negatively correlated with moderate-frequency amplitude-based intensity measures, and weakly positively correlated with low-frequency amplitude-based intensity measures and cumulative absolute velocity. Particular attenuation is given to the physical interpretation of the observed correlations, which can largely be explained as a result of: (a) the 5–75% significant duration () representing approximately the duration of body wave arrivals; and (b) the limited amount of energy contained in a ground motion time history. Finally, the practical application of the developed correlation equations in determining conditional distributions of ground motion duration for use in ground motion selection is demonstrated.