Abstract: A method for determining orientation of an electromagnetic survey sensor includes deploying the sensor at a selected position on the bottom of a body of water. An electromagnetic field is generated at a selected position in the body of water. A portion of the electromagnetic field is detected along at least two orthogonal directions at the sensor. A portion of the detected electromagnetic field is selected as having traveled only in a vertical plane which includes both source position and sensor position. The polarization direction of the selected portion of the electromagnetic field is determined from the selected portion. The determined polarization direction is used to determine the sensor orientation.

Abstract: A method for determining orientation of an electromagnetic survey sensor includes deploying the sensor at a selected position on the bottom of a body of water. An electromagnetic field is generated at a selected position in the body of water. A portion of the electromagnetic field is detected along at least two orthogonal directions at the sensor. A portion of the detected electromagnetic field is selected as having traveled only in a vertical plane which includes both source position and sensor position. The polarization direction of the selected portion of the electromagnetic field is determined from the selected portion. The determined polarization direction is used to determine the sensor orientation.

Abstract: A method for identifying features in the Earth's subsurface below a body of water using transient controlled source electromagnetic measurements includes acquiring a plurality of transient controlled source electromagnetic measurements. Each measurement represents a different value of an acquisition parameter. Each measurement is indexed with respect to a time at which an electric measuring current source is switched. The plurality of measurements is processed in a seismic trace display format, in which each trace corresponds to the measurement acquired for a value of the acquisition parameter. A subsurface feature is identified from the processed measurements.