Based on the Maxwell equation, the occurrences of
fractured zones are studied through the galvanic method. The
electrical and magnetic fields are first derived in the spatial
domain. To simplify the calculations, the computational formulas
of the electrical fields in the spatial domain are transformed into
the wavenumber domain by Fourier transform. The basic solution
of the electromagnetic field can thus be easily solved in the
wavenumber domain. According to the boundary conditions, a
recursive relationship between the different layers is established.
The electromagnetic fields are obtained through the recursive
relationships with the bottom-last layer. Finally, the apparent
resistivity is calculated using the surface electric field. A typical
goaf model is used for the numerical simulation. Based on the
modeling results the effectiveness of this method is determined.
The modeling results indicate that the galvanic method is very
effective for detecting the electrical anisotropic characters.