Method for 2D and 3D electromagnetic field measurements using a towed marine electromagnetic survey system

A method for acquiring electromagnetic data in at least two dimensions, comprising:

• towing a first streamer cable behind a vessel in a body of water, the first streamer cable comprising:
• a reference line extending substantially along the entire length of the cable;
• a plurality of spaced apart measuring electrodes disposed along the cable and electrically insulated from the reference line;
• and
• a plurality of voltage measuring circuits functionally coupled between each measuring electrode and the reference line;
• towing at least a second streamer cable behind the vessel at corresponding distance from the vessel as the first streamer cable, the second streamer cable configured substantially as the first streamer cable, the second streamer cable displaced from the first streamer cable in one of a horizontal plane and a vertical plane;
• at selected times, imparting an electromagnetic field in the body of water;
• measuring voltage difference at each measuring electrode with respect to the reference line;
• and
• determining a difference between voltages measured at least one electrode on each of the first and second streamer cables.