Studies of large-scale earth potentials across oceanic distances

• Published in: AT&T Technical Journal 1995-05, Vol.74 (3), p.73-84
• Main Authors: Lanzerotti, Louis J., Medford, Lester V., Maclennan, Carol G., Thomson, David J.
• Format: Article
• Language: English
• Subjects: Control systems; Earth; Geology; Magnetism; Q1
• ISSN: 8756-2324; 2376-676X; 1538-7305
• DOI: 10.1002/j.1538-7305.1995.tb00185.x

This paper describes some ongoing research to characterize and understand the large-scale (on the order of several thousand kilometers) geoelectric potentials that can be induced within the Earth by fluctuations of the geomagnetic field. An understanding of these induced potentials can be important for carrying out some geophysical investigations, as well as for solving numerous engineering problems related to the design and deployment of long, conducting installations on the Earth's surface. Such installations include the systems used to power long-distance cables, electrical power distribution networks, and pipeline corrosion-control systems. The magnitude of the induced potentials fluctuates significantly in time and in spatial extent. It reflects both the highly variable nature of the Earth's space plasma environment that produces the geomagnetic fluctuations and the heterogeneous nature of the geological structure of the Earth's surface and upper mantle. Present-day models of Earth's magnetic fluctuations are insufficient to predict the geopotentials reliably, particularly the extreme geopotentials that might be experienced on a specific long route. Thus, such geopotential measurements as those described in this paper on AT&T cables in the Atlantic and Pacific Oceans can contribute important knowledge of the Earth's geophysical environment, as well as new geopotential information for engineering design.