Use of the linear grid array in 2D resistivity tomography

In resistivity tomography, the choice of a particular array rather than another can bring substantial differences in results, also depending on the geometry and esistivity of investigated structures. Main differences regard spatial resolution, production of artefacts in the images as well as deviation from the true model resistivity. Recently, some multi-channel acquisition systems promoted using new array configurations, in addition to the “classical” ones, that enable many simultaneous measurements for each current injection dipole, thus reducing the field-work time significantly. Examples of this kind of arrays are the moving gradient array and the midpoint-potential-referred array (Dahlin and Zhou 2004). A 2D simplification of a multi-polar array previously optimized for a multi-channel acquisition (Cosentino and Martorana, 2003), is here tested and compared with other classical and efficient arrays (Wenner-Schlumberger and Dipole-Dipole), using numerical simulations and appropriate resistivity models.