A new method to extract strong velocity pulse in a pulse-like ground motion

Ground motions occurred in the near-fault region may generate strong pulses in the velocity-time signals, imposing greater threats to structures. To accurately and effectively characterize these pulse-like ground motion (PGM) signals, a new method based on shock-waveform decomposition is introduced to quantitatively represent and extract the strong velocity pulse from a given ground motion signal. In this study, the proposed method is applied to 91 benchmark PGM signals selected from the PEER ground motion database and 26 PGM signals from 6 February 2023 M_w 7.8 Turkey earthquakes to demonstrate its potential to accurately locate pulse positions and provide accurate waveform representations of the identified pulses. The results show that the proposed method can effectively address common issues in the existing approaches, particularly the widely-adopted Wavelet-Transform-based methods. The pulse(s) in single-pulse and double-pulse PGM signals can be represented respectively by the first and the first and second decomposed signal component (s) obtained using the proposed method. The pulse period (T_P) can be directly determined by the frequency parameter of the decomposed component. The obtained T_P values are generally consistent with those derived from other established approaches.