Volume 26 Number 4
  • E-ISSN: 1365-2478



In seismic refraction surveys, in particular those using first arrival recording techniques, the hidden layer problem occurs where energy from a refractor of higher velocity arrives at the surface before energy from an overlying refractor. The maximum thickness of the hidden layer is referred to as the blind zone.

Hypothetically, every recorded refractor has an associated blind zone which may or may not contain a hidden layer. For an assumed earth model of plane constant‐velocity layers and stepwise increase of velocity with depth, the effect of a blind zone on an interpreted depth section may be evaluated by defining an intercept time for a blind zone of assumed or known velocity and by using standard time‐term equations for layer thicknesses and depths.

The treatment covers an arbitrary number of blind zones embedded within a multilayer sequence of horizontal or dipping refractors. Model calculations affirm the benefits of this approach compared with previous methods which, in general, have been restricted to the case of two horizontal layers with one intermediate blind zone.


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  1. Banerjee, B., and Gupta, S. K., 1975. The hidden layer problem in seismic refraction work, Geoph. Prosp.23, 642–652.
    [Google Scholar]
  2. Green, R., 1962. The hidden layer problem, Geoph. Prosp.10, 166–170.
    [Google Scholar]
  3. Hawkins, L. V., 1961. The reciprocal method of routine shallow seismic refraction investigations, Geophysics26, 806–819.
    [Google Scholar]
  4. Hawkins, L. V., and Maggs, D., 1961. Nomograms for determining maximum errors and limiting conditions in seismic refraction surveys with a blind‐zone problem, Geoph. Prosp.9, 526–532.
    [Google Scholar]
  5. Hawkins, L. V., 1962. Discussion on the problem of the hidden layer within the blind zone, Geoph. Prosp.10, 548.
    [Google Scholar]
  6. Kaila, K. L., and Narain, H., 1970. Interpretation of seismic refraction data and the solution of the hidden layer problem, Geophysics35, 613–623.
    [Google Scholar]
  7. Knox, W. A., 1967. Multilayer near‐surface refraction computations, in Seismic refraction prospecting, edited by A. W.Musgrave , Society of Exploration Geophysicists Tulsa , Oklahoma , 197–216.
    [Google Scholar]
  8. Maillet, R., and Bazerque, J., 1931. La prospection seismique du sous-sol, Annales des Mines20, 314.
    [Google Scholar]
  9. Mooney, H. M., 1973. Handbook of Engineering Seismology, Bison Instruments Inc., Minneapolis, Minnesota, Chapter 9.
  10. Morgan, N. A., 1967. The use of the continuous seismic profiler to solve hidden layer problems, Geoph. Prosp.15, 35–43.
    [Google Scholar]
  11. Mota, L., 1954. Determination of dips and depths of geological layers by the seismic refraction method, Geoph. Prosp.19, 242–254.
    [Google Scholar]
  12. Odins, J. A., 1975. The application of seismic refraction to groundwater studies of unconsolidated sediments, Unpublished M.Sc. thesis, University of New South Wales, Kensington, 221 p.
  13. Puzyrev, N. N., 1972. On conditions for omission of layers during registration of the first arrivals, Academy of Sciences, Ukrainian S.S.R., GeophysicsVolume 48, 17–30 (in Russian).
    [Google Scholar]
  14. Soske, J. L., 1959. The blind zone problem in engineering geophysics, Geophysics24, 359–365.
    [Google Scholar]
  15. Stulken, E. J., 1967. Constructions, graphs and nomograms for refraction computations, in Seismic refraction prospecting, edited by A. W.Musgrave , Society of Exploration Geophysicists, Tulsa, Oklahoma, 312–314.
  • Article Type: Research Article
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