A Simulated earthquake ground motion f(t) is usually generated by using FFT. To generate f(t) using FFT, results in the problem of control of its characteristics based on the operation in frequency domain, by which the characteristics of f(t) are determined. Nonstationary characteristics of frequency and amplitude of f(t) are most important ones, and generally they are not discussed considering local shape of f(t). Local shape of f(t) gives a significant effect on the hysteretic response of structures. But this has not been actively considered in generating simulated earthquake ground motions. In this paper it is clarified that local shape of f(t) is closely related to φ^+(0) (see Fig. 1), generally some, _0φ_i (see Eqs. (13), (14) and Fig. 3), the values of Fourier phase spectrum. Actually simulated earthquake ground motions are generated considering φ^+(0) and some _0φ_i and it is demonstrated possible to control local shape of f(t) by selecting φ^+(0) and some _0φ_i corresponding to the shape.
