Abstract
THE so-called precursors to PKP consist of a train of arrivals preceding the core phase PKIKP, of small but variable amplitude, and commonly observed in the distance range 125° to 143°. Interpretations of this phenomenon have included dispersion near the boundary of the inner core1,2, diffraction from the PKP caustic3, sharp upward refraction within one or more transition layers surrounding the inner core4–6 and reflexions from small discontinuities at the boundaries of such transition layers7,8. In order to take account of certain unexplained features of the observations, Haddon9 recently advanced the alternative hypothesis that precursors are the result of scattering of PKP waves from irregularities in the vicinity of the core-mantle boundary. We examine the scattering hypothesis in more detail, and present evidence in its favour.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Gutenberg, B., Geophys. J., 1, 238 (1958).
Hai, N., Ann. Geophys., 19, 285 (1963).
Bullen, K. E., and Burke-Gaffney, T. N., Geophys. J., 1, 9 (1958).
Bolt, B. A., Bull. Seism. Soc. Amer., 54, 191 (1964).
Adams, R. D., and Randall, M. J., Bull. Seism. Soc. Amer., 54, 1299 (1964).
Ergin, K., J. Geophys. Res., 72, 3669 (1967).
Sacks, I. S., and Saa, G., Carnegie Institution Year Book 69, 419 (Washington, 1970).
Buchbinder, G., Bull. Seism. Soc. Amer., 61, 429 (1971).
Haddon, R. A. W., Trans. AGU, 53, 600 (1972).
Chernov, L. A., Wave Propagation in a Random Medium (trans. by Silverman, R. A.) (McGraw-Hill, New York, 1960).
Bullen, K. E., An Introduction to the Theory of Seismology, 222 (Cambridge Univ. Press, 1963).
Engdahl, E. R., thesis, Saint Louis Univ. (1968).
Subiza, G. P., and Bath, M., Geophys. J., 8, 496 (1963).
Hannon, W. J., and Kovach, R. L., Bull. Seism. Soc. Amer., 56, 441 (1966).
Husebye, E., and Madariaga, R., Bull. Seism. Soc. Amer., 60, 939 (1970).
Kovach, R. L., and Glover, P., Geophys. J., 15, 367 (1968).
Gogna, M. L., Geophys. J., 16, 489 (1968).
Bolt, B. A., O'Neill, M., and Qamar, A., Geophys. J., 16, 475 (1968).
Qamar, A., thesis, Univ. California at Berkeley (1971).
Wright, C., and Muirhead, K. J., J. Geophys. Res., 74, 2034 (1969).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
CLEARY, J., HADDON, R. Seismic Wave Scattering near the Core-Mantle Boundary: a New Interpretation of Precursors to PKP. Nature 240, 549–551 (1972). https://doi.org/10.1038/240549a0
Received:
Issue Date:
DOI: https://doi.org/10.1038/240549a0
This article is cited by
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
