The detection of lateral anisotropy of the ocean floor by electromagnetic methods

In a typical marine controlled-source electromagnetic (CSEM) experiment, one or more self-contained receivers capable of measuring small variations in the electromagnetic field are located in an array on the sea-floor. A remote horizontal electric dipole is towed close to the sea-floor by a surface vessel. Variations in the current through the dipole cause correlated variations in the electric and magnetic fields at the receivers. The variations contain information about the distribution of electrical conductivity of the subsurface rocks. The electrical conductivity is related to such critical physical parameters as porosity, temperature and fluid content.