Skip to main content
SpringerLink
Log in

TheSa phase from the Hindu Kush earthquake of July 6, 1962

  • Published:
Pure and Applied Geophysics PAGEOPH Aims and scope Submit manuscript

Summary

The Hindu Kush earthquake of July 6, 1962 produced anSa phase (vertical component or Rayleight type) which was clearly recorded at stations in North America in the distance range 90° to 110°. The propagation of this phase is studied in detail, both by the usual method of measuring velocity of first arrival and also by determining group velocities from the derivative of the phase of the Fourier transform (in the period range 20 to 80 seconds). The energy in theSa phase propagates in a manner intermediate between that of a single ray and that of a single isolated mode. The expected interference effects which vary as a function of distance are observed and complicate a straight-forward measurement of group velocities. The results are most reliable if only the group velocities corresponding to parts of the spectra with relatively high amplitudes are used.

The results show a regional variation in the velocity of the Rayleigh typeSa for continental areas, being higher under shield areas than under areas of more recent tectonic activity. The results are compared with theoretical calculations for the Gutenberg, Jeffreys-Bullen and Canadian Shield models of the Earth and the results indicate regional variations in shear velocity in the upper mantle extending to depths of several hundred km under continents.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Don L. Anderson andM. N. Toksöz,Surface waves on a spherical earth I. Upper mantle structure from Love waves, J. Geophys. Res.68, 11 (1963), 3483.

    Article  Google Scholar 

  2. M. Båth andA. L. Arroyo,Pa and Sa waves and the upper mantle, Geofis. Pura e Appl.56 (1963), 67.

    Article  Google Scholar 

  3. A. Ben-Menahem,Mode Ray Duality, Bull. Seismol. Soc. Am.45 (1964), 1315.

    Google Scholar 

  4. B. A. Bolt andJ. Dorman,Phase and group velocities of Rayleigh waves in a spherical, gravitating earth, J. Geophys. Res.66, (1961), 2965.

    Article  Google Scholar 

  5. J. N. Brune,Travel times, body waves and dispersion in the earth, Abstracts of papers submitted to the Annual Meeting of the Seismol. Soc. of Am., Seattle, Washington, Mar. 27–28 (1964).

  6. J. N. Brune,Travel times, body waves and normal modes of the earth, Bull. Seismol. Soc. Am.54 (1964), 2099.

    Google Scholar 

  7. J. N. Brune andN. J. Dorman,Seismic weavs and earth structure in the Canadian shield, Bull. Seismol. Soc. Am.53 (1963), 167.

    Google Scholar 

  8. P. Caloi,Onde longitudinali e transversali guidate dall'astenosfera, Rendiconti dell'Accademia Nazionale dei Lincei, serie VIII, XV, fasc,6 (1953), 352.

    Google Scholar 

  9. I. Lehmann,On the travel times of P as determined from nuclear explosions, Bull. Seismol. Soc. Am.54 (1964), 123.

    Google Scholar 

  10. R. L. Kovach andD. L. Anderson,Higher mode surface waves and their bearing on the structure of the earth's mantle, Bull. Seismol. Soc. Am.54 (1964), 161.

    Google Scholar 

  11. F. Press andM. Ewing,Waves with Pn and Sn velocity at great distances, Proc. Natl. Acad. Sci. U.S.41 (1955), 24.

    Article  Google Scholar 

  12. H. Takeuchi, M. Saito andN. Kobayashi,Theoretical dispersion curves of second mode mantle Rayleigh and Love waves for five earth models. Geophysical Notes, Geophysical Inst., Faculty of Sci., Univ. Tokyo16 (1963), 106.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. U.S.C.G.S., Lamont Geological Observatory, Palisades, N.Y.

    James N. Brune (Formerly Geophysicist)

  2. California Institute of Technology, Pasadena, California

    James N. Brune (Formerly Geophysicist)

Authors
  1. James N. Brune
    View author publications

    You can also search for this author in PubMed Google Scholar

Additional information

Lamont Geological Observatory, Contribution No. 883. Division of Geological Sciences, California Institute of Technology, Pasadena, Contribution No. 1378.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Brune, J.N. TheSa phase from the Hindu Kush earthquake of July 6, 1962. PAGEOPH 62, 81–95 (1965). https://doi.org/10.1007/BF00875289

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00875289

Keywords

Search

Navigation