Mapping subsurface fractures by radio-frequency holography: a simulation

Abstract

SUMMARY A computer simulation shows that radio‐frequency holography could probably be used for mapping fractures in otherwise fairly homogeneous low‐conductivity rock or salt. According to in situ measurements of the attenuation of electromagnetic waves in a variety of media, and according to our simulation, it should be possible to image fractures up to distances of 150 or 200 m, with a good resolution. One application is the selection of sites suitable for the storage of radioactive waste. Another is the prediction of earthquakes. Our simulation involves image reconstruction by Fourier optics, from noisy synthetic data that we assume to be taken down a single deep borehole. The computer code is available from the author.

Ground Penetrating Radar Attenuation Expressions in Shallow Groundwater Research

“…For instance, Lorrain (1991) investigated the radiofrequency holography technique for mapping of fractures in low-conductivity media and provided an in situ attenuation database for different geological materials. Turner and Siggins (1994) defined attenuation vs. frequency linear functions to deduce the attenuation of radio-waves over typical GPR bandwidths of certain geological materials.…”

Ray‐based synthesis of bistatic ground‐penetrating radar profiles

“…For a spherical wave (assuming a point dipole source), the amplitude in a homogeneous medium decreases as r-1 (e.g., Lorrain, 1991). In a medium in which the dielectric permittivity [and hence the propagation velocity, equation (1)] varies in space, the geometrical spreading effects may be calculated by integration along the raypath.…”