|Imaging in shot-geophone space|
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 -space into -space is lateral velocity variation . In this chapter, we will see how migration can be performed in the presence of by going to -space.
Unfortunately, this chapter has no prescription for finding , although we will see how the problem manifests itself even in apparently stratified regions. We will also see why, in practice, amplitudes are dangerous.