Tomographic analysis of crosshole seismic measurements

Seismic tomography is a new method to determine the properties of a rock volume. In Phase 2 of the Stripa programme seismic crosshole methods have been developed for measurements at up to 1 km distance. The work has been aimed at problems which are specific for seismic tomography, e.g. the fact that the field geometries will not in general allow a complete ray sampling of the area under study. This means that the usual so called transform methods of reconstruction, developed for medical tomography, are not applicable. However, the CG-algorithm applied to a quadratic functional is shown to give viable results