WERNER ARRAY

The Wenner array consists of four collinear, equally spaced electrodes. The outer two electrodes are typically the current (source) electrodes and the inner two electrodes are the potential (receiver) electrodes. The array spacing expands about the array midpoint while maintaining an equivalent spacing between each electrode. [1] The advantages of the Wenner array are that the apparent resistivity is easily calculated in the field and the instrument sensitivity is not as crucial as with other array geometries. Relatively small current magnitudes are needed to produce measurable potential differences.[2] The disadvantages are that for each sounding, all of the electrodes have to be moved to a new position. In order to image deep into the earth, it is necessary to use longer current cables; handling the cables and electrodes between each measurement can be cumbersome, especially in difficult terrain. The Wenner array is also very sensitive to near surface inhomogeneities which may skew deeper electrical responses