Geophysical Diffraction Tomography: Theory Implementation and Results
Final rept. 18 Aug 1988-1 Oct 1991
OAK RIDGE NATIONAL LAB TN
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Geophysical diffraction tomography GDT is a high resolution technique for quantitative subsurface imaging. The method is based on the analysis of data acquired from the propagation of scalar waves from an array of source positions to an array of receiver positions. Images of spatial variations in refractive index are produced by a procedure which propagates the received signal backwards through a subsurface cross-section. This is conceptually similar to the elements of optical holography. An acoustic-based GDT imaging procedure has been implemented using a specially developed data acquisition system employing a source deployed on the ground surface and an array of 29 hydrophones that are emplaced in a borehole. Confirmatory field studies have demonstrated that GDT can successfully image naturally-occurring and man-made buried features.