Abstract

This study proposed an alternative method to earthquake ground motion characterization based on composite-intensity index spectrum. It is a combination of spectral acceleration (Sa(T)), duration (D05-95) and peak ground velocity (PGV). The spectrum, considering the effect of three-component motions, was firstly introduced in the paper. It was established based on thirty-one three-component strong earthquake records that were collected worldwide. The index was further related to the modified Mercalli intensity scales to assign its damage potentials. The method revealed more meaningful interpretations of earthquake ground motion characterization than other procedures.