Method and system for seafloor geological survey using vertical electric field measurement

A system for modeling electrical conductivity of the seafloor, the system comprising a plurality of units deployed on the seafloor, each unit comprising:

• a frame adapted for deployment to the seafloor;
• a pair of horizontal dipoles extending from the frame in an orthogonal orientation relative to each other for generating a pair of first electric field signals;
• a pair of electrodes extending vertically from the frame and vertically displaced relative to each other to form a vertical dipole for generating a second electric field signal;
• at least one first amplifier in electrical communication with the horizontal and vertical dipoles for amplifying each of the first and second electric field signals, the first amplifier having a low input impedance and high gain;
• a data logging processor in electrical communication with each of the first amplifier for receiving amplified electric field signals and storing data representative thereof
• a clocking device for synchronizing operation of the data logging processor with other data logging processors on other units within the system;
• a power supply in electrical communication with the data logging processor, the clocking device and the first and second amplifiers;
• at least one housing for enclosing the data logging processor, the clocking device, the first amplifier and the power supply, the at least one housing adapted for corrosion and pressure resistance in seawater;
• means for deploying the unit to the seafloor;
• and
• means for retrieving the unit from the seafloor.

A method for modeling seafloor conductivity, comprising:

• deploying a plurality of units at different locations in an area of interest on the seafloor, wherein each unit includes:
• an assembly including a frame for supporting a plurality of electrodes, the assembly configured for resting on the seafloor;
• a first pair of electrodes, mounted in relation to the frame in vertical displacement from one another, to form a first vertical dipole, wherein each electrode of the dipole is in electrical communication with an output providing a signal that is induced by vertical electric fields present near the seafloor;
• using the units, sensing horizontal and vertical electric fields over a pre-selected spectrum;
• collecting data corresponding to the sensed electric fields from each of the plurality of units;
• and
• generating a model of resistivity using the collected data.