Influence of a Near-Surface Structure on Seismic Wave Fields and Multiple Suppression

The hybrid ray-reflectivity method is applied to the numerical modelliog of seismic wave fields in laterally varying layered models containing a thin near-surface low-velocity layer. The computatioos within the laterally varying layered model are performed by the ray method, but the thin near surface layer is attacked locally by the matrix methods. The thin layer need not be homogeneous, it may include arbitrary inner layeriog and it may lightly vary laterally. All multiples within the layer are automatically taken into account. Numerical examples of hybrid ray-reflectivity seismograms for two models of the thin near-surface layer are presented. An inverse algorithm to remove the effects of a thin near-surface layer from seismograms recorded at the Earth's surface is proposed.