Identification of near-fault multi-pulse ground motion

The near-fault pulse-like ground motion is of practical importance since it tends to cause severer damage to structures than ordinary ground motion in engineering and helps char-acterize the seismic source and the kinematic characteristics of the geological fault in seis-mology. However, previous investigations mainly focus on single-pulse ground motion. As one of the particular seismic records in the near-fault earthquake, the multi-pulse ground motion is rarely considered caused by the absence of an effective identification method. Hence, a generalized continuous wavelet transform (GCWT) method is proposed by com-bining convolution analysis with evaluation parameters to facilitate wider studies on multi -pulse ground motion. In identification, the proposed method requires each pulse in the multi-pulse ground motion to satisfy the same criteria and excludes the effects of attenu-ation component. In methodology, the proposed method overcomes the limitations of the classical CWT method that requires a wavelet basis and provides a workable and flexible framework for pulse-like ground motion identification. Based on the method, single-and multi-pulse ground motions from two typical near-fault earthquakes on the PEER NGA-West2 database were identified. The effects of the pulse model and ground motion orien-tation on identification are discussed. Besides, the 5% damped spectral velocity of multi -pulse ground motions potentially contain multiple peaks in the high-period range. This phenomenon implies that the risk would be underestimated for the response spectrum -based seismic hazards and risk analysis if the multi-pulse features are not, or are insuffi-ciently taken into account. (c) 2023 Elsevier Inc. All rights reserved.