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Reflection Tomography in 'Laterally Varying Media
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 3rd International Congress of the Brazilian Geophysical Society, Nov 1993, cp-324-00026
Abstract
In this paper, we will discuss a separate reconstruction of lateral velocity gradients and reflection Intorfaces using the method of reflection tomography. We will be limited by Inversion of traveltimes. As it Is known such inversion may suffer from a significant drawback: ambiguity. This ambiguity is referred to as depth/velocity ambiguity which is especially notable in the case of non-vertical angles of propagation. In tomographic experiments this ambiguity Is suppressed by finite angular aperture recording. The next problem is non-uniqueness. It will be shown that the lateral gradients of velocity and the depths to the reflection points can be uniquely recovered from surface seismic data in the reflection tomography experiments. Reflection data Inversion is done via an optimization process which can be formulated either in the physical space of seismic velocities or In the dual space of Lagrangian multipliers. We compare both methods and show the advantages of' the dual transform.