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Next: TOMOGRAPY OF REFLECTION DATA Up: Reproducible Documents

Imaging in shot-geophone space

Jon Claerbout

Till now, we have limited our data processing to midpoint-offset space. We have not analyzed reflection data directly in shot-geophone space. In practice this is often satisfactory. Sometimes it is not. The principal factor that drives us away from $(y,h)$-space into $(s,g)$-space is lateral velocity variation $v(x,z) \ne v(z)$. In this chapter, we will see how migration can be performed in the presence of $v(x,z)$ by going to $(s,g)$-space.

Unfortunately, this chapter has no prescription for finding $v(x,z)$, although we will see how the problem manifests itself even in apparently stratified regions. We will also see why, in practice, amplitudes are dangerous.