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** Up:** Appendix A: Downward Continuation-Migration
** Previous:** Forward operator: Migration

Equation (A-8) enables us to compute the image
corresponding to a given velocity field from data measured at the
surface of the earth, that is, to migrate the data. The operation
adjoint to migration, modeling, can be derived from the same equation
using the adjoint state system
| |
(18) |

where
- is the modeled data, computed for a given
velocity field.

Therefore, we can obtain the modeled data () from the
reflectivity image () by writing

| |
(19) |

** Next:** Appendix B: First-order Born
** Up:** Appendix A: Downward Continuation-Migration
** Previous:** Forward operator: Migration
Stanford Exploration Project

6/1/1999