3-D imaging of large scale buried structure by 1-D inversion of very earlytime electromagnetic (VETEM) data

A simple and efficient method for large scale three-dimensional (3-D) subsu rface imaging of inhomogeneous background is presented. One-dimensional (1- D) multifrequency distorted Born iterative method (DBIM) is employed in the inversion. Simulation results utilizing synthetic scattering data are give n. Calibration of the very early time electromagnetic (VETEM) experimental waveforms is detailed along with major problems encountered in practice and their solutions. This discussion is followed by the results of a large sca le application of the method to the experimental data provided by the VETEM : system of the U,S, Geological Survey. The method is shown to have a compu tational complexity that is promising for on-site inversion.