APPROXIMATE RULES FOR THE COMPOSITION OF APPARENT RESISTIVITY SECTIONS *

Consideration is given to the form of apparent resistivity sections obtained by varying electrode array position and spacing over two dimensional features.

Since basic solutions exist for horizontally layered media and for vertical or dipping single interfaces, simple rules are proposed whereby these solutions can be directly combined to give solutions for more complex sections. Substantial approximations may be involved as the rules do not fully allow for interactions between the constituents.

The range of error incurred in application of the rules is explored, with particular reference to the square array system of resistivity measurement. The two extremes‐ of orientation of the square array with respect to the line of section are separately considered in this survey.

Within appropriate limits, the rules appear extendable to a wide variety of simple structures for which rigorous solutions would be formidable. The rules are finally discussed in relation to practical applications.