Abstract: A method and apparatus for locating and evaluating surface and subsurface anomalies by detecting, monitoring or measuring transient or local variations respectively which occur in an alternating component of a vertical current having a frequency characteristic which emanates from the earth'surface in the region being monitored or measured. For locating fixed anomalies, local variations which occur in the amplitude, frequency and frequency modulation of the alternating component of the vertical current are measured. For detecting the passage of moving or transient anomalies, a stationary detector is positioned to detect any change in the vertical alternating current leakage in the vicinity of the detector which is caused by a moving or transient anomaly such as a submerged submarine, seismic activity, or sustained severe wheather. For accuracy enhancement and redundancy, simultaneous measurements of the signal strength in multiple frequency bands may be used.

Abstract: A microwave system for determining the volume fraction of water in a fluid. In the described application, the fluid is crude oil, and the system is used to determine the volume fraction of water in the crude oil. A microwave beam having a frequency which varies with time is transmitted through the liquid, and absorption losses are calculated. The volume fraction of water is determined according to the absorption losses.

Abstract: A microwave system for determining the volume fraction of water in a fluid. In the described application, the fluid is crude oil, and the system is used to determine the volume fraction of water in the crude oil. First and second microwave beams, differing in frequency, reception location, or both, are transmitted through the liquid, and respective absorption losses are calculated. The volume fraction of water is determined according to the absorption losses. Different reception locations are used to detect the passage of a large slug of water.