Electrical Tomography AC
Till this moment the use of Electrical Resistivity Tomography (ERT) for geology has always been basically the same since its debut, based on the original vertical Electrical Soundings (VES) principles: applying a continuous current to two stakes inserted into the ground and measuring the corresponding voltage between other two. The applied current and thus the relative tension have always been continuous, with an inversion in polarity for each measure. The new tool POLARES uses an alternate current, instead, sinusoidal type, with an adjustable frequency. Advantages of the new POLARES system: Considering the higher complexity of the device, the alternating current stimulation has shown particular advantages with regard to the faster implementation of the measures with the same quality of results. This higher speed can reduce the time required to perform a set of field measurements by a factor of at least 10 (or 20 in most cases!) in respect to traditional system. Moreover, the measure of the relationship between the detected voltage and the injected current, in sinusoidal state, both as form and as a phase (delay of a signal over the other), these two pieces of information, with only one measure, allow the simultaneous detection of the resistivity and the induced polarization of the ground.