First I show that equation (5) and (4)
are numerically equivalent and produce identical results, as predicted
analytically. Figure illustrates a wave field propagating
in the model that shows a step discontinuity but
is otherwise homogeneous.
The elastic wave propagates across a
discontinuity in *v*_{p} and *v*_{s}.
Figure shows a comparison of two
modeling responses. One result was calculated using equation (5)
and one result was obtained using equation (4).
For comparison I extract a single
trace from the recorded wave fields, as shown in Figure .
There is no noticeable difference between the two curves
for each of the two components. For both components the resulting responses
overlie each other perfectly and indicate that both modeling equations
are also numerically equivalent.

Figure 1

Figure 2

11/17/1997