This paper concerns with the dynamics of G type seismic waves in homogeneous isotropic layer overlying a non homogeneous isotropic half space. In this paper we have represented the low-velocity layer by assuming the variation in rigidity and density in the lower inhomogeneous isotropic half space. The inhomogeneous parameters governing the wave propagation, i.e. the rigidity and the density, are assumed to be functions of depth. Condition for a large amount of energy to be confined near the surface is found which indicates that a large portion of energy can flow along the interface for horizontally polarized shear waves with group velocity lower than the shear wave velocity in the upper mantle. Dispersion equations and the displacement in the upper layer are obtained for inhomogeneity parameter. Dispersion curves are plotted for different variation in inhomogeneity parameter. Effect of inhomogeneity is distinctly marked in the graphs. Variation in group velocity against scaled wave number is shown. Finally surface plot of group velocity is drawn for wave number and depth parameter.
