A numerical method is presented for computing ground surface displacements induced by a buried vertical point source in a three-dimensional layered elastic half-space. On the basis of parametric studies, the effects of source depth on the contribution of Rayleigh and body waves to the ground displacement are examined for two-layered media. It is shown that, when the source is in the surface layer, Rayleigh waves always dominate, except when the contrast between two layers are high and the normalized frequency is close to one. If the source is in the base layer, on the contrary, body waves tend to dominate in the frequency range slightly less than cutoff frequencies of higher Rayleigh modes.