Abstract
For studying non-stationary seismic ground response subjected to a strong earthquake motion, a new method is proposed. The method is time-frequency domain analysis using a fast wavelet transform, and non-stationary variation of shear stiffness and damping ratio are determined by dissipation energy and maximum shear strain amplitude. Most valuable point of the method is that the deterioration of shear stiffness can be obtained explicitly as a result of analysis. Applicability of the method to practical problem is studied by the case history of the seisimic array observation site of Kobe Port Island in the 1995 Kobe earthquake.
