1887
  1. Home
  2. A-Z Publications
  3. Geophysical Prospecting
  4. Volume 53, Issue 4
  5. Article
Volume 53, Issue 4
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

We analyse the problem of radiation of seismic waves by a vibroseis source when the baseplate is subject to flexure. A theoretical model is proposed to account for baseplate flexure, generalizing the well‐known model of the vibroseis source of Sallas and Weber, which was developed for a rigid plate. Using the model proposed, we analyse the effect of flexure on the properties of seismic waves. We show that the flexure does not contribute to the far‐field and mainly affects the readings of the reference accelerometer that is used to measure the force applied to the ground; these readings generally become dependent on the location of the sensor on the plate. For muddy and sandy soils, the effect of flexure on baseplate‐acceleration measurements is nonetheless pronounced at the high end of the vibroseis frequency band only (∼100 Hz), and is negligible at all frequencies for stiffer soils. The corresponding phase lags introduced by the flexural vibrations at high frequencies lead to errors in the traveltime measurements (through the cross‐correlation function) of up to 0.6 ms for muddy soils and less for denser soils. We show the existence of an optimal position of the reference sensor on the baseplate and also propose a general method of eliminating the phase lag due to the baseplate flexure in acceleration measurements.

Loading

Article metrics loading...

/content/journals/10.1111/j.1365-2478.2005.00492.x
2005-06-24
2024-04-25

  • From This Site

    /content/journals/10.1111/j.1365-2478.2005.00492.x
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. BaetenG. and ZiolkowskiA.1990. The Vibroseis Source . Elsevier Science Publishing Co.
     [Google Scholar]
  2. BycroftG.N.1956. Forced vibrations of a rigid circular plate on a semi‐infinite elastic space and on an elastic stratum. Philosophical Transactions of the Royal Society of LondonA248, 327–368.
    [Google Scholar]
  3. GladwellG.M.1968. The calculation of mechanical impedances relating to an indenter vibrating on the surface of semi‐infinite elastic body. Journal of Sound and Vibration8, 215–228.
    [Google Scholar]
  4. JohnsonK.L.1985. Contact Mechanics . Cambridge University Press.
    [Google Scholar]
  5. JungerM.C. and FeitD.1986. Sound, Structures and Their Interaction , 2nd edn.MIT Press, Cambridge , MA .
    [Google Scholar]
  6. KornG.A. and KornT.M.1968. Mathematical Handbook for Scientists and Engineers , 2nd edn.McGraw–Hill Book Co.
     [Google Scholar]
  7. LandauL.D. and LifshitzE.M.1959. Theory of Elasticity . Pergamon Press, Inc.
     [Google Scholar]
  8. LandauL.D. and LifshitzE.M.1976. Mechanics , 3rd edn.Pergamon Press, Inc.
     [Google Scholar]
  9. LebedevA.V. and BeresnevI.A.2004. Nonlinear distortion of signals radiated by vibroseis sources. Geophysics69, 968–977.
    [Google Scholar]
  10. LebedevA.V. and SutinA.M.1996. Excitation of seismic waves by an underwater sound projector. Acoustical Physics42, 716–722.
    [Google Scholar]
  11. LerwillW.E.1981. The amplitude and phase response of a seismic vibrator. Geophysical Prospecting29, 503–528.
    [Google Scholar]
  12. MartinJ.E. and JackI.G.1990. The behaviour of a seismic vibrator using different phase control methods and drive level. First Break8, 404–414.
    [Google Scholar]
  13. MillerG.F. and PurseyH.1954. The field and radiation impedance of mechanical radiators on the free surface of a semi‐infinite isotropic solid. Proceedings of the Royal Society (London)A223, 521–541.
    [Google Scholar]
  14. MorseP.M. and FeshbachH.1953. Methods of Theoretical Physics . McGraw–Hill Book Co.
     [Google Scholar]
  15. RobertsonI.A.1966. Forced vertical vibration of a rigid circular disc on a semi‐infinite solid. Proceedings of the Cambridge Philosophical Society: Mathematical Physics62, 547–553.
    [Google Scholar]
  16. SafarM.H.1984. On the determination of the downgoing P‐waves radiated by the vertical seismic vibrator. Geophysical Prospecting32, 392–405.
    [Google Scholar]
  17. SallasJ.J.1984. Seismic vibrator control and the downgoing P‐wave. Geophysics49, 732–740.
    [Google Scholar]
  18. SallasJ.J. and WeberR.M.1982. Comments on ‘The amplitude and phase response of a seismic vibrator’ by W.E. Lerwill. Geophysical Prospecting30, 935–938.
    [Google Scholar]
  19. SkudrzykE.1968. Simple and Complex Vibratory Systems . The Pennsylvania State University Press.
    [Google Scholar]
  20. TimoshenkoS. and Woinowsky‐KriegerS.1959. Theory of Plates and Shells , 2nd edn.McGraw–Hill Book Co.
     [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/j.1365-2478.2005.00492.x
Loading
Radiation from flexural vibrations of the baseplate and their effect on the accuracy of traveltime measurements
Geophysical Prospecting 53, 543 (2005); https://doi.org/10.1111/j.1365-2478.2005.00492.x
/content/journals/10.1111/j.1365-2478.2005.00492.x
/content/journals/10.1111/j.1365-2478.2005.00492.x
Loading

Data & Media loading...

  • Article Type: Research Article

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