Under previous NSF funding we conducted a novel experiment to study the internal structure of what appears to be the central uplift region of a fossil meteor crater near Kentland, Indiana. We request funds to analyze these data to refine our knowledge of their structure using three tools. (1) Analysis of 8 miles of reversed and split refraction data using conventional methods to resolve structural details around the edges of 1.5 by 2 mile rectangular study area. (2) Application of a new technique called fan shot geotomography that can be used to invert for lateral velocity variations on a two dimensional slice through the earth at the depth of the refracting layer. (3) Development and application of a new wavefield migration technique for imaging laterally reflected head waves. With this technique we hope to image major lateral discontinuties along a horizontal slice through the earth with a resolution comparable to normal incidence reflection data images of subsurface layering. The later two techniques require some additional technical development. With further development these techniques may prove valuable for application to future large scale investigations of lithospheric structure.
