COMPUTER DATA PROCESSING AND QUANTITATIVE INTERPRETATION OF AIRBORNE RESISTIVITY SURVEYS

The recently constructed airborne electromagnetic system called E-Phase measures the intensity of the vertical and horizontal electric fields. Standard broadcasting, VLF, and LF navigation aid transmitters are used as sources of the primary EM field. A system of this kind responds best to horizontal layers of large extent and therefore is suitable for geologic mapping and for the detection of resistive materials such as gravel and permafrost. A successful application of the system would not have been possible without digital recording of the data and subsequent computer processing. An efficient algorithm consisting of three processing cost and provides for two intermediate data checks. Final outputs are printer plots of apparent resistivity for all flight lines and maps of stacked profiles or contours. Quantitative interpretation was made possible by the simultaneous recording of the data at three transmitter frequencies and by the availability of theoretical solutions for layered media. Instead of generating an atlas of type curves, an interactive program was written which enables the geophysicist to rapidly obtain apparent resistivities assuming a three-layer model. A close match with the measured data is easy to achieve when a reasonable estimate of two of the parameters (resistivities, thicknesses) can be made initially. The interpretation procedure is demonstrated on a case history, a 1973 survey conducted near Wadena, Saskatchewan. /Author/

  • Corporate Authors:

    Society of Exploration Geophysicists

    Shell Building, P. O. Box 3098
    Tulsa, OK  USA  74101
  • Authors:
    • Palacky, G J
    • Jagodits, F L
  • Publication Date: 1975-10

Media Info

  • Features: Figures; References;
  • Pagination: p. 818-830
  • Serial:
    • Geophysics
    • Volume: 40
    • Issue Number: 5
    • Publisher: Society of Exploration Geophysicists

Subject/Index Terms

Filing Info

  • Accession Number: 00127250
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Nov 18 1975 12:00AM