GROUND-PENETRATING RADAR VELOCITY TOMOGRAPHY IN HETEROGENEOUS AND ANISOTROPIC MEDIA

A ray series solution for Maxwell's equations provides an efficient nu merical technique for calculating wavefronts and raypaths associated w ith electromagnetic waves in anisotropic media. Using this methodology and assuming weak anisotropy, we show that a perturbation of the anis otropic structure may be related linearly to a variation in the travel time of an electromagnetic wave. Thus, it is possible to infer lateral variations in the dielectric permittivity and magnetic permeability m atrices. The perturbation approach is used to analyze a series of cros swell ground-penetrating radar surveys conducted at the Idaho National Engineering Laboratory. Several important geological features are ima ged, including a rubble zone at the interface between two basalt hows. Linear low-velocity anomalies are imaged clearly and are continuous a cross well pairs.