Absolutely all migration algorithms can be considered to do one or the other of the processes described in this section. Which method we choose to use to explain observed events on imaged sections is pretty much a matter of choice. Diffracting amplitudes over specific curves or smiles is by far the most popular. Nevertheless, it is sometimes helpful to understand the alternative frown-based method. Before this frown-based approach can be fully appreciated, it is necessary to consider the geometrical aspects of data synthesis or seismic modeling. Chapter 3 reviews seismic modeling. Since seismic modeling must of course acquire data in some sense equivalent to normal acquisition procedures, Chapter 4 reviews how seismic data is acquired today.
