TRUNCATION EFFECT

We can see that the slopes of the lines on Figure c correspond to the slopes corresponding to the last trace of the gather (Fig. d). It suggests that the lines are due to the truncation effect and that they are parabolas. If they are parabolas they should turn into straight lines in $(\tau^2,m)$-space. The result is shown in Figure b. In the upper right part of the figure are lines dipping less steeply. This is due to the fact that truncation at low times occurs at lower offset (Figure ).

A velocity stack made with half of the marine gather is shown in Figure a. The slope is less steep and corresponds to that in Figure b.