The seismic quality factor, Q, is generally treated as frequency-independent, yet theory and field evidence suggest it may not be. We measure constant-Q and frequency-dependent Q(f), from downgoing direct-P arrivals in VSP data, over a 1000 m-thick granite interval in Cornwall, SW England, and a 700 m-thick interbedded shale-carbonate sequence in the Barents Sea, and find two significant results.

First, we obtain consistent constant-Q and Q(f) values, although Q(f) values vary smoothly, with frequency-specific ‘attenuation peaks’. In the granite, over 25–90Hz, constant-Q=7547, and Q(f)=35–100. For the sediments, over 15–110Hz, constant-Q=15240, and Q(f)=70–200. We conclude that our Q(f) workflow (using logarithmic decrement of individual frequencies’ amplitudes after geometric spreading corrections, so not imposing an analytic Q(f) form) is workable.

Second, attenuation in this granite is comparably high to that in these sediments. The granite has only naturally-occurring fractures, but they appear sufficient to increase attenuation above an intuitively-expected level. Well-log-based predictions of 1-D scattering contributions to attenuation, for both datasets, could clarify the origins of our measured Q(f).

Overall, we urge that more Q(f) measurements are made, to support of studies of subsurface petrophysical properties and application of signal-processing tools that account for attenuation in seismic imaging.


Article metrics loading...

Loading full text...

Full text loading...


  1. Bath, M.
    [1974] Spectral Analysis in Geophysics. Developments in Solid Earth Geophysics. Elservier, Amsterdam.
    [Google Scholar]
  2. Beckwith, J., Clark, R.A. and Hodgson, L.
    [2016a] The estimation of spectra from time-frequency transforms for use in attenuation studies. Geophysical Prospecting, 65(1), 204–220.
    [Google Scholar]
  3. [2016b] Estimating frequency-dependent attenuation quality factor values from pre-stack surface seismic data. Geophysics, 82(1), O11–O22.
    [Google Scholar]
  4. Gamar-Sadat, F., Janot, L., Carotti, D., Morante Gout, J., Mascomere, J.P. and Mikkelsen, G.
    [2016] Image Quality Enhancement Using Volumetric Q- tomography and Q-PSDM - Martin Linge Case Study. 78th EAGE Conference & Exhibition, Extended abstract.
    [Google Scholar]
  5. Jeng, Y., Tsai, J.Y. and Chen, S.H.
    [1999] An improved method of determining near-surface Q. Geophysics, 64(5), 1608–1617.
    [Google Scholar]
  6. Mangriotis, M.-D., RectorIII, J.W., Herkenhoff, E.F. and Neu, J.C.
    [2013] Scattering versus intrinsic attenuation in the vadose zone: A VSP experiment. Geophysics, 78(2), B49–B63.
    [Google Scholar]
  7. Maultzsch, S., Chapman, M., Liu, E. and Li, X-Y.
    (2003) Modelling frequency-dependent seismic anisotropy in fluid-saturated rock with aligned fractures: implication of fracture size estimation from anisotropic measurements. Geophysical Prospecting, 51, 381–392.
    [Google Scholar]
  8. [2007] Modelling and analysis of attenuation anisotropy in multi-azimuth VSP data from the Clair field. Geophysical Prospecting, 55, 627–642.
    [Google Scholar]
  9. Muller, T.M., Gurevich, B. and Lebedev, M.
    [2010] Seismic wave attenuation and dispersion resulting from wave-induced flow in porous rocks — A review. Geophysics, 75(5), 147–164.
    [Google Scholar]
  10. O’Doherty, R.F. and Anstey, N.A.
    [1971] Reflections on Amplitudes. Geophysical Prospecting, 19(3), 430–458.
    [Google Scholar]
  11. Pride, S.R., Harris, J.M., Johnson, D.L., Mateeva, A., Nihei, K.T., Nowack, R.L., Rector, J.W., Spetzler, H., Wu, R., Yamomoto, T., Berryman, J.G. and Fehler, M.
    [2003] Permeability dependence of seismic amplitudes. The Leading Edge, 22(6), 518–525.
    [Google Scholar]
  12. Sams, M.S., Neep, J.P., Worthington, M.H. and King, M.S.
    [1997] The measurement of velocity dispersion and frequency-dependent intrinsic attenuation in sedimentary rocks. Geophysics, 62(5), 1456–1464.
    [Google Scholar]
  13. Schoenberger, M. and Levin, F.K.
    [1974] Apparent Attenuation due to intrabed Multiples, Geophysics, 39(3), 278–291.
    [Google Scholar]
  14. Shapiro, S.A. and Hubral, P.
    [1999] Elastic Waves in Random Media: fundamentals of seismic stratigraphic filtering. Springer, Berlin.
    [Google Scholar]
  15. Ville, J.
    [1948] Théorie et applications de la notion de signal analytique. Cables et transmission, 2(1), 61–74.
    [Google Scholar]
  16. Wang, Y.
    [2006] Inverse Q-filter for seismic resolution enhancement. Geophysics, 71(3), V51–V60.
    [Google Scholar]

Data & Media loading...

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