Synthetic Test

Using the same synthetic model, and starting with a constant velocity 10% less than the background model velocity, we get a systematic bias in our best focusing $\gamma$, Figure 5 shows the same three CMP locations as Figures 3 and 4. In each case the best focusing $\gamma$ is significantly lower than when we started with the correct background velocity.

 

layer.wrong.vel
Figure 5 The best focusing $\gamma$at same 3 CMP locations. Left panel (CMP 8), focuses at 1.06, center panel (CMP 7) at .85, and right (CMP 6) at .93.