Electromagnetic geophysical survey systems and methods employing electric potential mapping

A geophysical survey system for mapping an electric potential field. There is an electromagnetic (EM) source (15A,15B) and geophysical survey cables (16) that each include electrodes (18) spaced apart along the geophysical survey cables, and data acquisition units (20) that obtain measurements of an electric potential between two electrodes. A modeling module (1013, Fig. 10) calculates a reference potential at a selected electrode for each of the geophysical survey cables, and a calculation module (1009, Fig. 10) to combine signals representative of the measurements to produce signals indicative of the electric potential of each electrode relative to the reference potential. There is a tracking module that monitors a position of each selected electrode relative to the EM source for each of the plurality of geophysical survey cables. There is a method associated with using the system. Each reference potential may be calculated by the modeling module based on the tracked position of the electrode. There is preferably a presentation module (1011, Fig. 10) that presents a geophysical survey map to a user based on the measurements. The calculation module may combine the measurements to formulate an electric potential map from which a mapping module may generate the geophysical survey map.