Model | In-line dip () | X-line dip () | Layer velocity (km/s) |

A | (0.0,5.0,10.0) | (0.0, 0.0, 0.0) | (1.5, 2.0, 2.5) |

B | (0.0,5.0,10.0) | (0.0, -5.0, 5.0) | (1.5, 2.0, 2.5) |

Table 1: Model parameters of Models A and B

Model | (m) | (m) | (m) |

A | 20 | 20 | 100 |

B | 20 | 20 | 50 |

Table 2: Acquisition parameters of Models A and B

Model A is designed so that the shotline and streamers
are deployed along the in-line dip direction. Therefore, there is no
approximation error in our approach. With 11 streamers covering from -500*m*
to +500*m* and a 100*m* streamer interval in the cross-line direction,
this is a wide azimuth survey.

For a given shot location, Figure 8 shows the ideal
multiple gather and the predicted one. Each 3-D MCG cube in this
example is first stacked along the in-line direction into a 2-D PSMCG
containing at most 11 traces sampled at intervals of 100*m*. The 2-D PSMCG
is then interpolated in the cross-line direction to be sampled at 25*m*
intervals. The interpolated PSMCG is further stacked into a trace.

Figure 8

Model B is a relatively narrow azimuth survey that still contains 11
streamers covering from -250*m* to +250*m* at 50*m* streamer intervals
in the cross-line direction. The bottom two reflectors in the model
have the opposite cross-line angles, which inevitably introduce
approximation error into the estimation. However, as shown in Figure
9, as long as the cross-line dips have no dominant
direction, the error can possibly be compensated for in the subtraction step.

Figure 9

4/20/1999