Underground Tomogram from Cross-Borehole Measurements

Abstract

Cross-borehole multifrequency continuous-wave radar measures the amplitudes and phases of the transmitted fields. This makes it possible to calculate the permittivity and conductivity averaged along the line connecting two receiving antennas with the transmitting antenna in the boreholes. Backprojections of these line-averaged parameters in the parallel and offset measurements give stable and smooth tomograms of subsurface permittivities and conductivities, except for isolated high-contrast objects such as the air tunnel. (C) 1998 John Wiley & Sons, Inc.