A stable geotomography technique for refractive media

The application of tomographical techniques to geophysical monitoring and exploration has been extended to media where refraction and reflection effects may be significant. The result is an iterative refinement scheme which is unstable in its original formulation. This paper presents the stability improvements of selective smoothing and path elimination which enable the reconstruction process to converge to an accurate solution. By use of the objective error measures of Euclidean distance and boundary definition by minimum variance partitioning, tomograms produced by this improved technique are shown to be superior to those obtained by traditional straight-line geotomography. Guidelines for practical application are presented.