| Abstract: | It is shown how to interpret, without curve-matching, Schlumberger resistivity soundings carried out with the array parallel to the surface trace of a vertical boundary plane separating two media with different resistivities (the vertical fault problem). To this end, it is demonstrated that the apparent resistivity function can be expressed as an Hankel-transformable integral that allows to invert the apparent resistivity curve into an associated resistivity transform curve. The study of the asymptotical properties of this function and of some mathematical properties of a related reduced transform function allows to realize a simple procedure for deriving the parameters of the model. In practice, this procedure consists in fitting a straight-line to a semi-logarithmic plot of the reduced transform function and in evaluating the intercept along the vertical axis and the slope. |
