The problem of transmission of an elastic wave through a homogeneous layer sandwiched between two homogeneous half spaces has been considered. The exact solution has been obtained and the results are shown graphically.
Viscoelastic theory developed in the past is historically examined and it is shown that the constancy of Q observed in the wide range of frequency is only an apparent phenomenon and there is no need of employing a nonlinear theory. Based on the linear theory it is proved that the dispersion and the dissipation of waves cannot be independent phenomena but are closely connected with each other. A simple calculation is presented with regard to Rayleigh and Love waves and then a method is suggested with which we can calculate the distribution of Q in the vertical direction within the earth.