The new “Maximum Yield Grid” (MYG) Array in Full 3D Resistivity Tomography

Over the past few years geoelectrical prospecting has experienced many innovations, ranging from instrumental refinements to improvement of data interpretation. The consequence of this has been a strong increase in the method s resolution power and, therefore, its field of application has broadened. Nevertheless, the diffusion of 3D surveys in electrical resistivity tomography has been very much limited by the long acquisition time required by this kind of investigation, as compared to 2D ERT or other geophysical exploration methods like GPR. However, 3D ERT has a great advantage in terms of resolution power, that is very important in many applications, such as archeological or cultural heritage surveys. Furthermore, the applicability of DC electrical resistivity tomography to media with precious and vulnerable exposed surfaces in the field of cultural heritage, has also been limited by the invasivity of geoelectrical prospecting: in fact it is usually necessary to insert the electrodes for current injections into small perforations on the acquisition surface. To overcome these limitations a new 3D array, named MYG, has been developed to minimize acquisition time (40 times smaller than that of classical arrays) and the invasivity of 3D ERT, and to enlarge its field of application in geophysical prospecting.