Experiment setup

The numerical experiment uses a highly realistic velocity model composed of stratigraphically plausible succession of reflectors superimposed over a linearly increasing background velocity. Figure displays some properties of the velocity model.

 

velomod Figure 1 Left: Background velocity; Right: Histogram of velocity deviation from the background, in percentages, for a random number of samples in a certain region of the model.

The velocity variations are sufficiently abrupt to cause massive multiple internal reflections when modeled with a two-way propagation algorithm. Figure shows both multiple-free data created with a one-way algorithm (split-step with three reference velocities) and multiple-affected data created with a finite-difference algorithm. Vertical streaks of high-amplitude focusing are visible, especially in the multiple-free panel.

 

zoff
Figure 2 Zero-offset data. Left: without multiples; Right: with multiples.