The model configuration in Figure 13 describes a finite bounded area in two dimensions. When a propagated wave arrives in the neighborhood of the boundary, we must consider the effects of the reflected wave. Are reflected waves wanted? Is a reflected wave a physical phenomenon, or is it an artifact? What are the consequences of the finite nature of the model? What are the directions of the arriving waves, and is the numerical method sufficiently robust to eliminate the reflected waves? We will assume the model is sufficient in size to include all significant reflection events within the time recording window. The actual geological structure which is being modeled might be quite large compared with the area of the computational model of Figure 13.

Figure 13: Geological Model.