1887
Volume 40, Issue 1
  • ISSN: 0812-3985
  • E-ISSN: 1834-7533

Abstract

The tau-p inversion algorithm is widely employed to generate starting models with most computer programs, which implement refraction tomography. This algorithm emphasises the vertical resolution of many layers, and as a result, it frequently fails to detect even large lateral variations in seismic velocities, such as the decreases which are indicative of shear zones. This study demonstrates the failure of the tau-p inversion algorithm to detect or define a major shear zone which is 50 m or 10 stations wide. Furthermore, the majority of refraction tomography programs parameterise the seismic velocities within each layer with vertical velocity gradients.

By contrast, the Generalized Reciprocal Method (GRM) inversion algorithms emphasise the lateral resolution of individual layers. This study demonstrates the successful detection and definition of the 50 m wide shear zone with the GRM inversion algorithms. The existence of the shear zone is confirmed by a 2D analysis of the head wave amplitudes and by numerous closely spaced orthogonal seismic profiles carried out as part of a later 3D refraction investigation. Furthermore, an analysis of the shot record amplitudes indicates that a reversal in the seismic velocities, rather than vertical velocity gradients, occurs in the weathered layers.

The major conclusion reached in this study is that while all seismic refraction operations should aim to provide as accurate depth estimates as is practical, those which emphasise the lateral resolution of individual layers generate more useful results for geotechnical and environmental applications. The advantages of the improved lateral resolution are obtained with 2D traverses in which the structural features can be recognised from the magnitudes of the variations in the seismic velocities. Furthermore, the spatial patterns obtained with 3D investigations facilitate the recognition of structural features such as faults which do not display any intrinsic variation or ‘signature’ in seismic velocities.

© 2009 ASEG
Loading

Article metrics loading...

/content/journals/10.1071/EG08119
2009-03-01
2026-01-13

  • From This Site

    /content/journals/10.1071/EG08119
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. Aki K. , and Richards P. G. 2002, Quantitative Seismology: University Science Books.
  2. Barton R. Barker N. 2003 Velocity imaging by tau-p transformation of refracted traveltimes: Geophysical Prospecting 51195 203 doi:10.1046/j.1365-2478.2003.00365.x
    [Google Scholar]
  3. Berry M. J. 1971 Depth uncertainties from seismic first arrival studies: Journal of Geophysical Research 766464 6468 doi:10.1029/JB076i026p06464
    [Google Scholar]
  4. Červený V. , and Ravindra R. 1971, Theory of Seismic Head Waves. University of Toronto Press.
  5. Chopra S. , and Marfurt K. J. 2007, Seismic Attributes for Prospect Identification and Reservoir Characterization. Geophysical Developments No. 11, SEG, Tulsa.
  6. de Franco R. 2005 Multi-refractor imaging with stacked refraction convolution section: Geophysical Prospecting 53335 348 doi:10.1111/j.1365-2478.2005.00478.x
    [Google Scholar]
  7. Domzalski W. 1956 Some problems of shallow refraction investigations: Geophysical Prospecting 4140 166 doi:10.1111/j.1365-2478.1956.tb01401.x
    [Google Scholar]
  8. Drijkoningen G. G. 2000 The usefulness of geophone ground-coupling experiments to seismic data: Geophysics 651780 1787 doi:10.1190/1.1444862
    [Google Scholar]
  9. Hagedoorn J. G. 1955 Templates for fitting smooth velocity functions to seismic refraction and reflection data: Geophysical Prospecting 3325 338 doi:10.1111/j.1365-2478.1955.tb01379.x
    [Google Scholar]
  10. Hagedoorn J. G. 1959 The plus-minus method of interpreting seismic refraction sections: Geophysical Prospecting 7158 182 doi:10.1111/j.1365-2478.1959.tb01460.x
    [Google Scholar]
  11. Hagiwara T. Omote S. 1939 Land creep at Mt Tyausu-Yama (Determination of slip plane by seismic prospecting): Tokyo University Earthquake Research Institute Bulletin 17118 137
     [Google Scholar]
  12. Hawkins L. V. 1961 The reciprocal method of routine shallow seismic refraction investigations: Geophysics 26806 819 doi:10.1190/1.1438961
    [Google Scholar]
  13. Healy J. H. 1963 Crustal structure along the coast of California from seismic-refraction measurements: Journal of Geophysical Research 685777 5787
     [Google Scholar]
  14. Ivanov J. Miller R. D. Xia J. Steeples D. Park C. B. 2005 a The inverse problem of refraction travel times, part I; types of geophysical nonuniqueness through minimization: Pure and Applied Geophysics 162447 459 doi:10.1007/s00024-004-2615-1
    [Google Scholar]
  15. Ivanov J. Miller R. D. Xia J. Steeples D. 2005 b The inverse problem of refraction travel times, part II; quantifying refraction nonuniqueness using a three-layer model: Pure and Applied Geophysics 162461 477 doi:10.1007/s00024-004-2616-0
    [Google Scholar]
  16. Lanz E. Maurer H. Green A. G. 1998 Refraction tomography over a buried waste disposal site: Geophysics 631414 1433 doi:10.1190/1.1444443
    [Google Scholar]
  17. Merrick N. P. Odins J. A. Greenhalgh S. A. 1978 A blind zone solution to the problem of hidden layers within a sequence of horizontal or dipping refractors: Geophysical Prospecting 26703 721 doi:10.1111/j.1365-2478.1978.tb01630.x
    [Google Scholar]
  18. Nettleton L. L. , 1940, Geophysical prospecting for oil. McGraw-Hill Book Company.
  19. Oldenburg D.W. 1984 An introduction to linear inverse theory: Trans IEEE Geoscience and Remote Sensing GE-22665 674
     [Google Scholar]
  20. Palmer D. 1980, The generalized reciprocal method of seismic refraction interpretation Society of Exploration Geophysicists, 104 pp.
  21. Palmer D. 1986, Refraction seismics: the lateral resolution of structure and seismic velocity Geophysical Press.
  22. Palmer D. 1991 The resolution of narrow low-velocity zones with the generalized reciprocal method: Geophysical Prospecting 391031 1060 doi:10.1111/j.1365-2478.1991.tb00358.x
    [Google Scholar]
  23. Palmer D. 1992 Is forward modeling as efficacious as minimum variance for refraction inversion? Exploration Geophysics 23261 266; 521 doi:10.1071/EG992261
    [Google Scholar]
  24. Palmer D. 2001 a Imaging refractors with the convolution section: Geophysics 661582 1589 doi:10.1190/1.1487103
    [Google Scholar]
  25. Palmer D. 2001 b Resolving refractor ambiguities with amplitudes: Geophysics 661590 1593 doi:10.1190/1.1487104
    [Google Scholar]
  26. Palmer D. 2001 c Measurement of rock fabric in shallow refraction seismology: Exploration Geophysics 32307 314 doi:10.1071/EG01307
    [Google Scholar]
  27. Palmer D. 2003, Application of amplitudes in shallow seismic refraction inversion 16th ASEG Conference and Exhibition, Adelaide (Abstract).
  28. Palmer D. 2006 Refraction traveltime and amplitude corrections for very near-surface inhomogeneities: Geophysical Prospecting 54589 604
     [Google Scholar]
  29. Palmer D. 2007, Is it time to re-engineer geotechnical seismic refraction methods? 19th ASEG Conference and Exhibition, Perth (Extended Abstract).
  30. Palmer D. 2008 Is it time to re-engineer geotechnical seismic refraction methods? First Break 2669 77 doi:10.1002/9780470432723
    [Google Scholar]
  31. Palmer D. 2009, Integrating short and long wavelength time and amplitude statics (preprint).
  32. Palmer D. Nikrouz R. Spyrou A. 2005 Statics corrections for shallow seismic refraction data: Exploration Geophysics 367 17 doi:10.1071/EG05007
    [Google Scholar]
  33. Palmer D. Jones L. 2005 A simple approach to refraction statics with the generalized reciprocal method and the refraction convolution section: Exploration Geophysics 3618 25 doi:10.1071/EG05018
    [Google Scholar]
  34. Palmer D. Shadlow J. 2008 Integrating long and short wavelength statics with the generalized reciprocal method and the refraction convolution section: Exploration Geophysics 39139 147 doi:10.1071/EG08019
    [Google Scholar]
  35. Ruijtenberg P. A. , Buchanan R. , and Marke P. 1992, Three-dimensional data improve reservoir mapping In Sheriff, R.E. ed., Reservoir Geophysics. SEG, Tulsa, 122–130.
  36. Schuster G. T. Quintus-Bosz A. 1993 Wavepath eikonal traveltime inversion: theory: Geophysics 581314 1323 doi:10.1190/1.1443514
    [Google Scholar]
  37. Sjögren B. 2000 A brief study of the generalized reciprocal method and some limitations of the method: Geophysical Prospecting 48815 834 doi:10.1046/j.1365-2478.2000.00223.x
    [Google Scholar]
  38. Slichter L. B. 1932 Theory of the interpretation of seismic travel-time curves in horizontal structures: Physics 3273 295 doi:10.1063/1.1745133
    [Google Scholar]
  39. Stefani J. P. 1995 Turning-ray tomography: Geophysics 601917 1929 doi:10.1190/1.1443923
    [Google Scholar]
  40. Treitel S. Lines L. 1988 Geophysical examples of inversion (with a grain of salt): Leading Edge 732 35 doi:10.1190/1.1439464
    [Google Scholar]
  41. Whiteley R. J. 1986, Electrical and seismic response of shallow volcanogenic massive sulphide ore deposits Ph D Thesis, University of New South Wales, 393 pp.
  42. Whiteley R. J. Greenhalgh S. A. 1979 Velocity inversion and the shallow seismic refraction method: Geoexploration 17125 141 doi:10.1016/0016-7142(79)90036-X
    [Google Scholar]
  43. Zhang J. Toksöz M. N. 1998 Nonlinear refraction traveltime tomography: Geophysics 631726 1737 doi:10.1190/1.1444468
    [Google Scholar]
  44. Zhu X. Sixta D. P. Andstman B. G. 1992 Tomostatics: turning-ray tomography + static corrections: Leading Edge 1115 23 doi:10.1190/1.1436864
    [Google Scholar]
/content/journals/10.1071/EG08119
Loading
Maximising the lateral resolution of near-surface seismic refraction methods FN1
Exploration Geophysics 40, 85 (2009); https://doi.org/10.1071/EG08119
/content/journals/10.1071/EG08119
/content/journals/10.1071/EG08119
Loading

Data & Media loading...

  • Article Type: Research Article
Keyword(s): 2D; 3D; GRM; near-surface; RCS; resolution; seismic refraction

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error