Correlation of Arias intensity with amplitude, duration and cumulative intensity measures

This manuscript examines the correlation of Arias intensity (AI) with nine amplitude-, duration-, and cumulative-based ground motion intensity measures. The correlations are determined using ground motions from active shallow crustal earthquakes in the NGA-West1 database, and recently developed ground motion prediction equations (GMPEs). Multiple GMPE combinations and bootstrap sampling are used to explicitly consider correlation uncertainties due to model selection and finite sample effects, respectively. It is shown that AIAI is highly correlated with high-frequency amplitude-based intensity measures and negatively correlated with significant duration intensity measures. AIAI also has a strong, but not perfect, correlation with cumulative absolute velocity (CAVCAV), which is also a cumulative measure of ground motion severity. Particular attention is given to the physical interpretation of the observed correlations of AIAI and other intensity measures, often in comparison to those obtained with CAVCAV. Parametric equations are developed to enable the obtained correlations to be easily used in applications such as ground motion selection and vector hazard analysis.