A simulation method of earthquake ground motion in consideration of time-varying phase based on nonstationary spectrum theory

摘要

This paper presents a nonstationary simulation method of earthquake motion. The equation of simulation is derived from the evolutionary spectrum theory without an assumption of a modulationg function imposed on a conventional simulation method. As a result, this method includes a nonstationary phase that is named "time-varying phase" as a new parameter. Numerical results demonstrate that simulated earthquakes by this method agree with a based model more closely than those by the conventional method. In addition, the fluctuation of the time-varying phase is assessed using the concept of instantaneous frequency.