Reverse Time Migration of up and down going signal for ocean bottom data

Artifacts in Ocean-Bottom RTM

The two artifacts that appear in Figure 5(a) can be identified when migrating with only up-energy and with only down-energy. The deeper artifact ($\approx$ 1300 m) appears in Figure 5(b) while the 1200 m artifact appears in figure 5(c). These artifacts do not appear in streamer RTM. When injecting the down-going data into the finite difference grid, the signal actually spreads both upward and downward in the computation grid. This creates spurious events when correlating, because down-going energy should only travel upward in reverse time. Similarly, up-going data should only traverse downward when injected in reverse time to the finite-difference grid. To alleviate this problem, we propose a joint inversion scheme. Such a scheme not only addresses the artifacts problem, it also provides a way to constructively combine up- and down-going migration results.

Reverse Time Migration of up and down going signal for ocean bottom data