Synthetic data in Figure 7 shows the result of convolution before and after NMO. An event labeled ``G" marks the tail-end of the source signature.
Figure 7 Example of convolution before and after NMO. The raw data shows a uniform primary-to-tail interval, while the NMO'ed data shows uniform multiple reverberation. The letters F, G, and V are adjustable parameters in the interactive program controlling water depth, signature tail, and velocity.
The main idea illustrated by the figure is that some events are equally spaced before NMO, while other events are equally spaced after NMO. We will see that proper deconvolution requires a delicious mixture of NMO and deconvolution principles.
Figure 7 happens to have a short time constant with the signature and a longer one with the reverberation. The time constants would be reversed in water shallow compared with the gun's quieting time. This is shown in Figure 8.
Figure 8 Model in water shallow compared to gun quieting time.
This figure shows an interesting interference pattern that could also show up in amplitude versus offset studies.