We propose a quantitative phase model to predict element waves of adjacent element faults to simulate ground motion using the stochastic Green's function method. We paired seismic records under the specified conditions of near-identical magnitude and hypocenter depth. To model the acceleration waveform similarities of the seismic record pair, a relationship between the mean value of Fourier amplitudes and an absolute value of Fourier phase difference was represented using a beta distribution. We then derived a regression formula of beta-distribution shape parameters with respect to the distance between the two hypocenters of each pair. Based on the proposed model, a seismic wave was synthesized, along with a calculated RMS error in acceleration response spectra between the synthesized wave and the observed record of the 2016 Kumamoto earthquake. It was confirmed that the proposed model decreased the error successfully.