Intermediate and Deep Properties of the Earth's Crust, a Possible Electromagnetic Wave Guide

  1. John G. Heacock
  1. John G. Heacock

Published Online: 15 MAR 2013

DOI: 10.1029/GM014p0001

The Structure and Physical Properties of the Earth's Crust

The Structure and Physical Properties of the Earth's Crust

How to Cite

Heacock, J. G. (1971) Intermediate and Deep Properties of the Earth's Crust, a Possible Electromagnetic Wave Guide, in The Structure and Physical Properties of the Earth's Crust (ed J. G. Heacock), American Geophysical Union, Washington D. C.. doi: 10.1029/GM014p0001

Author Information

  1. Earth Physics Program Office of Naval Research, Arlington, Virginia 22217

Publication History

  1. Published Online: 15 MAR 2013
  2. Published Print: 1 JAN 1971

ISBN Information

Print ISBN: 9780875900148

Online ISBN: 9781118664049

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Keywords:

  • Crustal environment;
  • Crustal wave guides;
  • Earth's crust;
  • Electromagnetic wave;
  • Lithospheric wave;
  • Resistivity;
  • Seismic low-velocity zones;
  • Sialic low-velocity zones

Summary

The idea that an eiectromagnetic wave guide may exist in the earth was postulated some 10 years ago on the assumption that conductive, wet surface layers and conductive, hot mantle layers enclose a resistive zone ot dry ‘basement’ rocks. Little is known in detail about the precise nature of the materials and physical properties of the deeper parts of the earth's crust, where, the resistive ‘basement’ rocks were presumed to exist. If a zone of sufficiently resistive rocks exists in the deeper continental crust. the case is argued on the basis of evidence from seismic data that continuous zones of resistive rocks may exist and may continue beneath tectonic belts and geologic province boundaries relatively undisturbed. Recent studies of crustal resistivities suggest that, at least in stable continental areas, magnitudes. of 106 to 107 ohm-m may exist; the latter value is high enough to give attenuations of less than 0.1 db/km in wave guide propagation. The need for conducting laboratory studies in coordination with geophysical field programs in order to interpret the materials, processes, and physical properties in the deeper parts of the earth's crust is emphasized. Major benefits to mankind can result for a variety of reasons from an improved understanding of this part of our environment.