What is Schlumberger array in 2D ERT survey?
This array is applicable for fixed cross section scan measurement; electrode arrangement and movement are as follows.
The measured pseudo-section is an inverted trapezoid (above).
First, AM=MN=NB is fixed distance/spacing between electrodes. System moves electrodes A, B, M, N rightwards point by point, and thus get the first profile. Then system increases the distance between the AM, NB by one electrode spacing, electrode M, N keeps one electrode spacing, system moves electrodes A, B, M, N rightwards point by point, and we get another profile; continue scan measuring like this, and finally we get a pseudo-section in inverted trapezoid.