Source

A device that emits a controlled electromagnetic signal with a frequency distribution and waveform designed to meet the needs of each survey

The source is towed above the seabed during electromagnetic surveys or at the sea surface for shallow water surveys. An electromagnetic field is generated by the source and propagates as a function of the resistivity of the surroundings. Controlled-source electromagnetic surveying methods measure and map contrasts in subsurface resistivity, for example, between hydrocarbon and non-hydrocarbon bearing sediments.