In this paper, the coherence functions and transfer functions between the Fourier amplitudes, those between the Fourier phases of seismic waves recorded at several observation points in Higashimatsuyama instrument array were estimated by use of statistical methods proposed on the base of the least square variance technique. The relationship between the coherency and the estimated propagate transfer function of waves were derived. The following results are obrained; 1) The coherency of the Fourier amplitude between seismic waves is higher than that of the Fourier phase. 2) The coherency of the propagation transfer functions between seismic waves is dependent on that of the Fourier phase. These results indicated that the uncorrelated waves as noise exert the greater influence on the Fourier phase of seismic waves than on the Fourier amplitude. Those uncorrelated waves can be attributed to the scattering waves caused by irregularities of the soil structure.
