A Horizontal Vector Approach to 3d Electrical Resistivity Tomography

Electrical resistivity tomography (ERT) is commonly implemented with collinear electrode arrays that measure only electric field components along the survey line, neglecting horizontal variations in other directions. This limitation is acceptable in two-dimensional (2D) ERT but can be significant in three-dimensional (3D) settings with complex geometry and strong resistivity contrasts. We propose measuring horizontal vector components of electric field variations, allowing determination of both magnitude and direction of surface electric field changes. Although full inversion tests are not included, incorporating such measurements into inversion frameworks may improve the resolution and reliability of 3D ERT. This concept may provide a new perspective on data acquisition and inversion parameterization.