Depth of Investigation and Vertical Resolution of Surface Geoelectric Arrays

Abstract

Depth of investigation and vertical resolution values are determined and tabulated for 30 surface geoelectric arrays that have non-zero response, i.e., a depth of investigation characteristic (DIC) function due to a buried thin horizontal sheet. In accord with experience, results show a general reciprocal relationship between depth of investigation and vertical resolution. The most frequently used arrays in multi-electrode studies (i.e., Wenner-[Formula: see text], Wenner-[Formula: see text], Schlumberger, dipole-axial arrays and the pole-dipole array) offer reasonable compromises between depth of investigation and vertical resolution. Depth of investigation can be increased by using the pole-pole array; vertical resolution can be improved with, for example, the [Formula: see text] or [Formula: see text] arrays. Current focussing does not increase the depth of investigation for the horizontal thin-sheet model. The complete set of depth of investigation and vertical resolution values permits exact physical comparison of various geoelectric arrays and provides simple but useful rules for practical geoelectric applications, e.g., how to develop multi-electrode systems with higher vertical resolution, or how to select arrays to satisfy special exploration requirements.