1887

Abstract

Summary

A highly localized and extremely low Q is detected through multiple measurements from seismic datasets acquired for mineral exploration in the Athabasca Basin, Canada. Q estimation methods used are time-domain amplitude decay, frequency-domain spectrum ratio, and velocity dispersion. The results confirm that locally Q can be smaller than 10, which is lower than all the values reported for marine and land seismic exploration datasets associated with either gas anomalies or volcanic studies. The very strong attenuation of seismic waves in the Athabasca Basin was previously assumed to occur because of the overburden. However, low Q observed over the entire borehole extent indicates it reflects deep rock anelastic properties. We have also discovered an azimuth-dependent nature of both the velocity and Q through the analyses of the manually picked first break traveltimes and waveforms from the surface data. Variations of velocity appear to be primarily affected by the local topography while behaviours of Q reflect deeper features such as fault zones and fault associated alterations. Such environments are challenging for seismic imaging as the signal-to-noise ratio is strongly reduced. However, low-Q zones may be footprint indicator.

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/content/papers/10.3997/2214-4609.201601397
2016-05-30
2024-04-26
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References

  1. Bath, M.
    , 1974. Spectral analysis in geophysics. Developments in Solid Earth Geophysics, M.Bath (ed.), Vol. 7. Elsevier Science Publishing Co.
    [Google Scholar]
  2. Cavalca, M., Moore, I., Zhang, L., Ng, S.L., Fletcher, R.P. and Bayly, M.P.
    , 2011, May. Ray-based tomography for Q estimation and Q compensation in complex media. In 73rd EAGE Conference & Exhibition.
    [Google Scholar]
  3. Futterman, W.I.
    , 1962. Dispersive body waves. Journal of Geophysical Research, 67(13), pp.5279–5291.
    [Google Scholar]
  4. Hale, D.
    , 1981. An inverse Q-filter. Stanford Exploration Project, 26, pp.231–244.
    [Google Scholar]
  5. Juhojuntti, N., Wood, G., Juhlin, C., O’Dowd, C., Dueck, P. and Cosma, C.
    , 2012. 3D seismic survey at the Millennium uranium deposit, Saskatchewan, Canada: Mapping depth to basement and imaging post-Athabasca structure near the orebody. Geophysics, 77(5), pp.WC245–WC258.
    [Google Scholar]
  6. Liu, H.P., Anderson, D.L. and Kanamori, H.
    , 1976. Velocity dispersion due to anelasticity; implications for seismology and mantle composition. Geophysical Journal International, 47(1), pp.41–58.
    [Google Scholar]
  7. Liu, X., Zhao, D. and Li, S.
    , 2014. Seismic attenuation tomography of the Northeast Japan arc: insight into the 2011 Tohoku earthquake (Mw 9.0) and subduction dynamics. Journal of Geophysical Research: Solid Earth, 119(2), pp.1094–1118.
    [Google Scholar]
  8. Malehmir, A., Durrheim, R., Bellefleur, G., Urosevic, M., Juhlin, C., White, D.J., Milkereit, B. and Campbell, G.
    , 2012. Seismic methods in mineral exploration and mine planning: A general overview of past and present case histories and a look into the future. Geophysics, 77(5), pp.WC173–WC190.
    [Google Scholar]
  9. Margrave, G.F.
    , 1998. Theory of nonstationary linear filtering in the Fourier domain with application to time-variant filtering. Geophysics, 63(1), pp.244–259.
    [Google Scholar]
  10. Shen, Y., Biondi, B. and Clapp, R.
    , 2015, December. Wave-Equation Based Q Tomography From Angle-Domain Common Image Gathers. In 2015 SEG Annual Meeting. Society of Exploration Geophysicists.
    [Google Scholar]
  11. Sun, L.F., Milkereit, B. and Schmitt, D.R.
    , 2009. Measuring velocity dispersion and attenuation in the exploration seismic frequency band. Geophysics, 74(2), pp.WA113–WA122.
    [Google Scholar]
  12. Tonn, R.
    , 1991. The determination of the seismic quality factor Q from VSP data: A comparison of different computational methods. Geophysical Prospecting, 39(1), pp.1–27.
    [Google Scholar]
  13. Wood, G., O’Dowd, C., Cosma, C. and Enescu, N.
    , 2012. An interpretation of surface and borehole seismic surveys for mine planning at the Millennium uranium deposit, northern Saskatchewan, Canada. Geophysics, 77(5), pp.WC203–WC212.
    [Google Scholar]
  14. Zhou, J., Wu, X., Teng, K., Xie, Y., Lefeuvre, F., Anstey, I. and Sirgue, L.
    , 2014, June. FWI-guided Q Tomography for Imaging in the Presence of Complex Gas Clouds. In 76th EAGE Conference and Exhibition 2014.
    [Google Scholar]
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