Zero-offset migration

Kirchhoff migration of field data

Figure 5.12 shows migrated field data.

The on-line movie behind the figure shows the migration before and after amplitude gain with time. You can get a bad result if you gain up the data, say with automatic gain or with $t^2$, for display before doing the migration. What happens is that the hyperbola flanks are then included incorrectly with too much strength.

The proper approach is to gain it first with $\sqrt{t}$ which converts it from 3-D wavefields to 2-D. Then migrate it with a 2-D migration like kirchfast(), and finally gain it further for display (because deep reflectors are usually weaker).

wgkirch
Figure 12. Kirchhoff migration of Figure .

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Zero-offset migration