A tunnel resolution investigation using an automated resistivity tank analog
J. Karwatowski and G.M. Habberjam
Journal name: Geophysical Prospecting
Issue: Vol 29, No 6, December 1981 pp. 891 - 905
Info: Article, PDF ( 993.01Kb )
The examination of apparent resistivity space sections over two-dimensional targets requires the accumulation of large amounts of data, if the resistivity field is to be adequately described.
Whilst such data may be obtained from an intensive sounding traverse in the field, it is desirable for interpretation purposes to be able to generate such space sections for a range of model variations.
Within their limitations, tank analogs can be used to provide such interpretation material, but the collection of data can itself be time-consuming. In this paper, an account is given of the development of an automated tank analog, where an entire space section can be scanned and the output obtained in paper tape format for later processing on a digital computer. The resistance measurement accuracy attained is comparable with normal field measurement accuracy.
A practical example of the use of this analog in investigating the problem of resolving and discriminating between two horizontal cylindrical tunnels is given. This problem is basic to an understanding of the minimum size and disposition of targets which can be observed on a space section. The square array has been used in this example because of its good resolution properties in general prospecting rather than its particular suitability for the targets investigated. The directional response of the array is also illustrated and discussed.