Geomagnetic noise reduction from sea surface, high sensitivity magnetic signals using horizontal and vertical gradients

Beside the Earth's magnetic field, the most important magnetic field in the sea is the field created by remanant and induced magnetization in the rocks and sediments of the sea bottom. But the geomagnetic induction originating from the Earth's external magnetic field constitutes an anomalous noise when mapping the geologic field, specially in coastal areas where the so called coast effect enhances the geomagnetic perturbation. A method for eliminating most of the geomagnetic noise from the recorded signals has been set up by treatment of measured gradients at the sea surface.