valencia@sep.stanford.edu

## ABSTRACTA complex velocity model can cause shadow zones in an image computed by migration due to poor illumination. These shadow zones may contain weak signals masked by artifacts. To reduce artifacts and recover the real signal, a target-oriented wave-equation inversion scheme can be developed that uses an explicitly computed least squares inversion Hessian. To solve the otherwise ill-conditioned inversion problem a model regularization needs to be added. One choice for regularization is to use the customary damping in the image space, another is to penalize the energy in the image not focused at zero subsurface-offset. To apply the second, the subsurface-offset Hessian needs to be computed by using the adjoint of migration as the modeling operator. Results on Sigsbee model show encouraging results. |

- Introduction
- Linear least-squares inversion
- Numerical results: Sigsbee model
- Conclusions
- Acknowledgments
- REFERENCES
- About this document ...

5/6/2007