ABSTRACT
The purpose of this paper is to develop a method to simulate the earthquake motion phase for simulating a design response compatible earthquake acceleration time history. A method is developed to calculate the earthquake motion phase as a function of the circular frequency without the unwrap procedure. Then the earthquake motion phase is decomposed into a linear delay and fluctuation parts. The fluctuation part of phase is named the phase throughout of this paper. First, a mean phase gradient is defined by dividing the phase difference with its circular frequency interval. The probability density characteristics of the mean phase gradient is discussed, and it is found that the mean phase gradient is obeyed the Levy-flight distribution. A new stochastic process is developed and named the fractional Levy-flight process to simulate the mean phase gradient.
