Quantitative identification of pulse-like ground motions based on intrinsic time-scale decomposition technique

Pulse-like earthquake ground motions may cause great seismic demands in engineering structures, and identifying these ground motions is significant in earthquake engineering. The intrinsic time-scale decomposition (ITD) is a self-adaptive time-frequency decompaction method that decomposes signals into proper rotation components. The instantaneous frequency and amplitude of the components are well defined, and the temporal information of frequency and amplitude has the exact resolution with the time-scale of extreme of the original signal. ITD was introduced in this study to decompose the non-stationary earthquake ground motion signals. A procedure for filtering and extracting the low-frequency pulses was constructed, and a quantitative criterion for classifying the pulse-like ground motions was proposed. The proposed method was tested on many ground motions and compared with the existing classification methods. The proposed method was demonstrated as an effective way to identify the pulse-like ground motion records, which can be readily implemented in earthquake engineering practices.