Stationary source for marine electromagnetic surveying

Disclosed are methods and systems for using electromagnetic sources that are substantially stationary in a body of water while electromagnetic field signals are detected with electromagnetic sensors towed through the body of water. An embodiment discloses an apparatus comprising: a vessel; a first electromagnetic source coupled to the vessel and configured to have a dipole moment oriented in a first direction; and a second electromagnetic source coupled to the vessel and configured to have a dipole moment oriented in a second direction, wherein the second direction is generally orthogonal to the first direction. Another embodiment discloses a system comprising: a sensor streamer configured for towing in a body of water, wherein the sensor streamer comprises a plurality of electromagnetic sensors disposed at spaced apart positions; and an electromagnetic source assembly configured for deployment at a substantially stationary position in the body of water.