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Improved 3D pole‐dipole resistivity surveys using radial measurement pairs
Author(s) -
Nyquist Jonathan E.,
Roth Mary J. S.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl024153
Subject(s) - equipotential , cartesian coordinate system , isotropy , dipole , electrode , anisotropy , voltage , electrode array , noise (video) , symmetry (geometry) , electrical resistivity and conductivity , physics , geometry , materials science , optics , computer science , mathematics , quantum mechanics , artificial intelligence , image (mathematics)
For convenience in the field, multielectrode arrays used to collect 3D resistivity data are typically laid out in a Cartesian grid with potential measurements made using electrode pairs oriented in the X and Y axis directions. The current flow away from a given injection electrode, however, has radial symmetry in the case of a homogeneous, isotropic half‐space, and near‐radial symmetry otherwise, unless the ground is extremely heterogeneous or anisotropic. Consequently, many of the voltage measurements made using standard electrode combinations are tangential or nearly‐tangential to the voltage equipotentials, resulting in a poor signal‐to‐noise ratio. We compare data collected using a standard pole‐dipole configuration with measurements made using the same Cartesian array, but choosing electrode pairs that lie along lines radiating away from the injection electrode. The remarkable improvement in data quality using a radial data acquisition pattern illustrates the importance of considering the potential gradient when designing resistivity data collection schemes.