The alternative to wave equation methods is a numerical damping zone, as in Figure 16, which reduces the wave strength over a grid region near the boundary. The idea is to slowly and smoothly apply a weight which will be effective in the aggregate. The product , , is computed to a small factor with the property of certain smoothness at both edges. The smoothness is required to reduce the unwanted reflections.

Figure 16: Computational Model Damping Zone.

Figure 17: Geological Model.

Figure 18: Model Boundary Damping Nodes, Left Side.