Design and construction of a resistivity meter for shallow investigation

Abstract

The cost of brand new resistivity meters (Scintrex, Bison, ABEM) has gone up astronomically. Consequently many institutions that need this equipment for teaching and research purposes cannot afford the price. This predicament compelled the authors to look for electronic components that are available in local markets and shops to fabricate this meter. This simple resistivity meter was then designed and constructed using components purchased locally. It measures current and voltage separately. The resistance is then computed from these readings. A comparison test was conducted with this meter using the ABEM Terrameter SAS 300 as the standard meter. The field testing exercise was conducted on an open field with a flat terrain. The results / data from the two instruments are very comparable; almost the same for a spread of /= 100m. Beyond this spread, the difference in readings is much. Hence, the use of this system is limited to shallow investigations where the target depth is not more than fifty metres (50m). Efforts are being made to improve on its performance.

Keywords: Design and construction, resistivity meter and field testing.

Nigerian Journal of Physics Vol. 18 (2) 2006: pp. 261-270