1887
Volume 32 Number 4
  • E-ISSN: 1365-2478

Abstract

A

The dynamic finite‐element method allows frequency‐dependent reflection and transmission coefficients to be computed for Love waves scattered by two‐dimensional inhomogeneities in coal seams.

Clean faults of zero hade angle show a throw‐dependent cross‐over frequency in reflection spectra, and throw‐dependent conversion from fundamental to first higher mode energy in transmission spectra. Oblique faults show mode conversion in reflection spectra which is relatable to the fault hade angle by simple Huygens‐theory models. Thin fracture zones or dykes normal to the seam show a reflection maximum when thickness of the zone is of order one quarter of the seam wave wavelength.

Published field data from two known faults and a dyke are compared with the modeling results and support the belief that broad‐band seam‐wave data are capable of characterizing a seam discontinuity (throw, hade angle, dyke thickness) as well as locating it. Development of such procedures will require extensions to existing field practice and processing.

This research was funded in part by the National Energy Research Development and Demonstration Council of Australia. The authors thank The Broken Hill Proprietary Company Limited for permission to quote from company case histories.

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References

  1. Asten, M. W.1982, Geophysical borehole logging and the prediction of static‐load rock strength, in Workshop on Geotechnical Logging of Boreholes, Australian Geomechanics Society and Institution of Engineers, Parkville , Victoria , Australia .
    [Google Scholar]
  2. Buchanan, D. J., Davis, R., Jackson, P. J. and Taylor, P. M.1981a, Fault location by channel wave seismology in United Kingdom coal seams, Geophysics46, 994–1003.
    [Google Scholar]
  3. Buchanan, D. J., Davis, R., Jackson, P. J. and Taylor, P. M.1981b, Fault detection in coal by channel wave seismology: some case histories, Bulletin of the Australian Society of Exploration Geophysicists12, 13–19.
    [Google Scholar]
  4. Crampin, S.1975, Distinctive particle motion of surface waves as a diagnostic of anistropic layering, Geophysical Journal of the Royal Astronomical Society40, 177–186.
    [Google Scholar]
  5. Drake, L. A. and Bolt, B. A.1980, Love waves normally incident at a continental boundary, Bulletin of the Seismology Society of America70, 1103–1123.
    [Google Scholar]
  6. Drake, L. A.
    and Asten, M. W. 1982, Wave propagation in irregular coal seams, in Finite Element Methods in Engineering—Proceedings of the Fourth International Conference in Australia on Finite Element methods (eds P. J.Hoadley and L. K.Stevens ) Dept of Civil Engineering, University of Melbourne, Parkville , Victoria .
    [Google Scholar]
  7. Evison, F. F.1955, A coal seam as a guide for seismic energy, Nature (London)176, 1224–1225.
    [Google Scholar]
  8. Freystätter, S. and Dresen, L.1977, Propagation of Rayleigh channel waves in coal seams—model seismic investigations, Journal of Geophysics43, 807–828 (English abstract, German text).
    [Google Scholar]
  9. Freystätter, S. and Dresen, L.1978, The influence of obliquely dipping discontinuities on the use of Rayleigh channel waves for the in‐seam seismic reflection method, Geophysical Prospecting26, 1–15.
    [Google Scholar]
  10. Guu, J. Y.1975, Studies of seismic guided waves: the continuity of coal seams, PhD Thesis, Colorado School of Mines, Denver .
  11. Klinge, U. J., Arnetzl, H. H., Krey, Th and Rüter, H.1981, Trends in the detection of coal seam discontinuities by in‐seam seismic techniques, in Third International Coal Exploration Symposium, Calgary ( G. O.Argall ), pp. 172–194, Miller Freeman, San Francisco .
    [Google Scholar]
  12. Korn, M. and Stöckl, H.1982, Reflection and transmission of Love channel waves at coal seam discontinuities computed with a finite difference method, Journal of Geophysics50, 171–176.
    [Google Scholar]
  13. Krey, T. C.1963, Channel waves as a tool of applied geophysics in coal mining, Geophysics28, 701–714.
    [Google Scholar]
  14. Lysmer, J. and Drake, L. A.1972, A finite element method for seismology in Methods of Computational Physics vol. 11 ( B. A.Bolt ), pp. 181–216, Academic Press, London .
    [Google Scholar]
  15. Mason, I. M., Buchanan, D. J. and Booer, A. K.1980, Fault location by underground seismic survey, Proceedings of the Institute of Electrical Engineers, 127F, 322–336.
    [Google Scholar]
  16. Millahn, K. O. and Marschall, R.1980, Two‐component in‐seam seismics. Paper presented at 50th Annual Meeting of Society of Exploration Geophysicists, Houston , 1980 November.
    [Google Scholar]
  17. Rüter, H.
    and Schepers, R. 1979, In‐seam seismic methods for the detection of discontinuities applied to West German coal deposits in Coal Exploration vol. 2 (ed. ( G. O., Argall ), Proceedings of the 2nd International Coal Exploration Symposium, Denver 1978, Miller Freeman, San Francisco .
    [Google Scholar]
  18. Su, F.C.1976, Seismic effects of faulting in coal seams: numerical modeling, PhD Thesis, Colorado School of Mines, Denver .
  19. Wilson, R.G. and Buchanan, D.J.1982, British in‐seam seismic methods for detection of faults in Australian coal mines. Paper B1, 6th International Committee of Coal Research Conference, Barbicon Centre, London 4–8 October 1982.
    [Google Scholar]
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