A procedure for stable electrical measurements on a rock sample against high contact resistance as a prerequisite for electrical tomography

Earth, Planets and Space

Table 7 Measurement results for the high-resistivity plastic sample (AS R11)

Sample	Pair of potential electrodes	Mean and standard deviation		Estimated sample resistivity (Ω m)
Sample	Pair of potential electrodes	Injected current (nA)	Potential difference (V)	Estimated sample resistivity (Ω m)
AS R11	P₂–P₃	29.5 ± 0.1	6.64 ± 0.01	1.35 × 10⁷
	P₅–P₃		3.15 ± 0.01	1.28 × 10⁷
	P₄–P₁		3.28 ± 0.01	1.33 × 10⁷
	P₄–P₆		2.45 ± 0.01	1.26 × 10⁷