Magnetics: Anomalies and Sensor Types

  • The magnetic anomaly can be reconstructed by approximating the subsurface target as a magnetic dipole with induced polarization parallel to the Earth’s magnetic field. Superposition of both fields defines the anomaly.

  • The magnetic anomaly shape depends on latitude. It typically has a bipolar shape with positive, negative excursions.

  • Sensor types are differentiated between measurements of the total field (proton precession) or individual field components (flux gate) magnetometers. The sensitivty is typically smaller than nT.

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Anomaly of induced magnetic dipole in northern Hemisphere