A PC-based tool for 2D resistivity/IP modelling and field data inversion

Indueed Polarization (lP) surveys allows the eharacterization of subsurface materials in terms of two electrical parameters: resistivity (p) and chargeability (m). This has numerous interesting applications in exploration geophysics when resistivity alone is not diagnostic enough to solve a given task. For example lP has been successfully used for the exploration of disseminated base metal sulfides deposits, resistive silicified massive base metal sulfides deposits and disseminated pyrite and arsenopyrite associated with gold mineralization. lP is also used for the characterization of sand/clay sequences for groundwater investigations and for environmental assessment applications. One of the most common way of implementing the lP technique on the ground surface is through 'sounding/profiling' surveys where standard (ABMN) electrodes arrays are used with multiple electrode separations to realize the sounding function while the array is moved longitudinally along the profile; common arrays are identified as 'pole-dipole', 'dipole-dipole' etc. The results of such surveys have been, very often, presented as pseudo-sections where the displayed pseudo-depth of the observed readings is a simple function of the electrodes' separation. Such pseudo-sections however display a considerably distorted and misleading view of the spatial distribution of each physical property values (p & m) at least for the untrained observer. This problem is eliminated with the generation of imaging cross-sections displaying with acceptable accuracy the true spatial distribution ofthe p & mvalues. This is the purpose ofthis PC-based 2D modelling tooI.