An electromagnetic method of mapping subsurface geological conditions which can produce a more accurate reading with fewer drill holes than conventional techniques is being developed. Called high-frequency electromagnetic probing, the system relies on transmitters and receivers that are lowered into drilled holes. Geologic anomalies such as tunnels, caverns or sudden changes in rock formations can be detected because they alter the intensity of radio waves passing through them. Spacing of the holes depends on the geologic conditions and purpose of the mapping; signals have been sent between holes 3,200 ft. apart. A variation of the technique could be used in site selection for dams and waste disposal areas and for oil exploration. For these applications, a liquid whose electrical conductivity is different from that of the surrounding rock is injected into an area, and its path is tracked by monitoring radio signals received in various bore holes.

  • Availability:
  • Corporate Authors:

    McGraw-Hill, Incorporated

    330 West 42nd Street
    New York, NY  United States  10036
  • Publication Date: 1977-7-7

Media Info

  • Features: Photos;
  • Pagination: p. 11
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00158151
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 8 1977 12:00AM