1887
Volume 64, Issue 3
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

When a seismic source is placed in the water at a height less than a wavelength from the water–solid interface, a prominent S‐wave arrival can be observed. It travels kinematically as if it was excited at the projection point of the source on the interface. This non‐geometric S‐wave has been investigated before, mainly for a free‐surface configuration. However, as was shown in a field experiment, the non‐geometric S‐wave can also be excited at a fluid–solid configuration if the S‐wave speed in the solid is less than the sound speed in the water. The amplitude of this wave exponentially decreases when the source is moved away from the interface revealing its evanescent character in the fluid. In the solid, this particular converted mode is propagating as an ordinary S‐wave and can be transmitted and reflected as such. There is a specific region of horizontal slownesses where this non‐geometric wave exists, depending on the ratio of the S‐wave velocity and the sound speed of water. Only for ratios smaller than 1, this wave appears. Lower ratios result in a wider region of appearance. Due to this property, this particular P‐S converted mode can be identified and filtered from other events in the Radon domain.

Loading

Article metrics loading...

/content/journals/10.1111/1365-2478.12287
2015-09-09
2024-03-29
Loading full text...

Full text loading...

References

  1. AkiK. and RichardsP.G.2002. Quantitative seismology, 2nd ed. University Science Books.
    [Google Scholar]
  2. AlloucheN., DrijkoningenG.G., VersteegW. and GhoseR.2011. Converted waves in a shallow marine environment: experimental and modeling studies. Geophysics76(1), T1–T11.
    [Google Scholar]
  3. BrekhovskikhL.M.1960. Waves in Layered Media. Academic Press: New York, NY.
    [Google Scholar]
  4. ChapmanC.2004. Fundamentals of Seismic Wave Propagation. Cambridge University Press.
    [Google Scholar]
  5. DaleyP.F. and HronF.1983. Nongeometric arrivals due to highly concentrated sources adjacent to plane interfaces. Geophysical Journal International73, 1655–1671.
    [Google Scholar]
  6. DaleyP.F. and HronF.1988. A non‐geometrical SH‐arrival. Bulletin of the Seismological Society of America36, 430–445.
    [Google Scholar]
  7. de HoopA.T. and van der HijdenJ.H.M.T.1983. Generation of acoustic waves by impulsive line source in a fluid/solid configuration with a plane boundary. Journal of the Acoustic Society of America74, 333–342.
    [Google Scholar]
  8. DeansD.R.1983. The Radon Transform and Some of its Applications. John Wiley and Sons: New York, NY.
    [Google Scholar]
  9. DrijkoningenG.G. and ChapmanC.H.1988. Tunneling rays using the Cagniard‐de Hoop method. Bulletin of the Seismological Society of America78, 898–907.
    [Google Scholar]
  10. FuchsK. and MúllerG.1971. Computation of synthetic seismograms with the reflectivity method and comparison with observations. Geophysical Journal of the Royal Astronomical Society23, 417–433.
    [Google Scholar]
  11. GutowskiP.R., HronF., WagnerD.E. and TreitelS.1984. S*. Bulletin of the Seismological Society of America74, 61–78.
    [Google Scholar]
  12. HongT.L. and HelmbergerD.V.1977. Generalized ray theory for dipping structure. Bulletin of the Seismological Society of America67, 995–1008.
    [Google Scholar]
  13. HronF. and MikhailenkoB.G.1980. Discovery of a new nongeometrical S* arrival generated at a free interface. In Proceedings of the 17th Assembly of the European Seismological Commission, pp. 293–297.
  14. HronF. and MikhailenkoB.G.1981. Numerical modeling of nongeometrical effects by theAlekseev‐Mikhailenko method. Bulletin of the Seismological Society of America71, 1011–1029.
    [Google Scholar]
  15. RothM. and HolligerK.2000. The non‐geometric PS wave in high‐resolution seismic data: observations and modelling studies. Geophysical Journal International140, F5–F11.
    [Google Scholar]
  16. SchmidtH.1988. SAFARI User's Guide. SACLANT Undersea Research Centre: La Spezia, Italy.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/1365-2478.12287
Loading
/content/journals/10.1111/1365-2478.12287
Loading

Data & Media loading...

  • Article Type: Research Article
Keyword(s): Non‐geometric waves; Radon transform; S‐waves

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