Skip to main content
SpringerLink
Log in

Slowness and azimuth at the Uppsala array

Part 2: Structural Studies

  • Published:
pure and applied geophysics Aims and scope Submit manuscript

Summary

From the Uppsala tripartite array,dT/dΔ and azimuth are determined for 181P and 24PKP phases. Near-surface lateral inhomogeneity is found from azimuth deviations to be small, equivalent to <3° dip on the Moho. Slowness, corrected for this structure, is divided into two azimuthal groups: from an ‘Asian’ group are indicated higherP velocities in the lower mantle and a lowerP-velocity gradient in the uppermost mantle, probably a low-velocity layer; the remainingdT/dΔ, from N, W and S azimuths, indicate a more normal velocity profile. There is evidence for a narrow zone of rapid transition between these two structural groups along the Arctic-Soviet continental margin. The few core phases indicate aBolt, rather than aJeffreys, type of core model.

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. R. D. Adams andM. J. Randall,The fine structure of the Earth’s core, Bull. Seism. Soc. Am.54 (1964), 1299.

    Google Scholar 

  2. M. Båth,Methods to improve seismograph data, Scientia102 (1967), 304 (English), 146 (French).

    Google Scholar 

  3. M. Båth andA. Lopez Arroyo,Pa and Sa waves and the upper mantle, Geofisica Pura e Appl.56 (1963), 67.

    Article  Google Scholar 

  4. B. A. Bolt,The velocity of seismic waves near the Earth’s center, Bull. Seism. Soc. Am.54 (1964), 191.

    Google Scholar 

  5. B. A. Bolt,Estimation of PKP travel times, Bull. Seism. Soc. Am.58 (1968), 1305.

    Google Scholar 

  6. H. Borg andM. Båth,The Uppsala seismograph array station, Pure and Appl. Geophys.89 (1971), 19.

    Article  Google Scholar 

  7. R. J. Brown,Lateral inhomogeneity in the crust and upper mantle from P-wave amplitudes, Pure and Appl. Geophys. (in press, 1972).

  8. R. J. Brown,Azimuthally varying P-wave travel-time residuals in Fennoscandia and lateral inhomogeneity, Pure and Appl. Geophys. (in press, 1973).

  9. R. J. Brown,Slowness and azimuth at the Uppsala array, part 1: array calibration and event location, Pure and Appl. Geophys. (in press, 1973).

  10. R. J. Brown, H. Borg andM. Båth,Strike and dip of crustal boundaries—a method and its application, Pure and Appl. Geophys.88 (1971), 60.

    Article  Google Scholar 

  11. G. G. R. Buchbinder,Distance corrections for deep focus earthquakes, Geophys. J. R. Astr. Soc.17 (1969), 195.

    Google Scholar 

  12. M. A. Chinnery,Velocity anomalies in the lower mantle, Phys. Earth and Planet. Interiors2 (1969), 1.

    Article  Google Scholar 

  13. M. A. Chinnery andM. N. Toksöz,P-wave velocities in the mantle below 700 km, Bull. Seism. Soc. Am.57 (1967), 199.

    Google Scholar 

  14. J. R. Cleary, C. Wright andK. J. Muirhead,The effects of local structure upon measurements of the travel time gradient at the Warramunga seismic array, Geophys. J. R. Astr. Soc.16 (1968), 21.

    Google Scholar 

  15. D. J. Corbishley,Multiple array measurements of the P-wave travel-time derivative, Geophys. J. R. Astr. Soc.19 (1970), 1.

    Google Scholar 

  16. D. J. Corbishley,Structure under seismic arrays, Geophys. J. R. Astr. Soc.21 (1970), 415.

    Google Scholar 

  17. D. J. Doornbos andE. S. Husebye,Array analysis of PKP phases and their precursors, in a NORSAR report (in press, 1972).

  18. M. A. Enayatollah,Travel times of P-waves for the Swedish-Finnish seismograph network, Pure and Appl. Geophys.94 (1972), 101.

    Article  Google Scholar 

  19. M. A. Enayatollah,Continental-array measurements of P-wave velocities in the mantle, Pure and Appl. Geophys.94 (1972), 136.

    Article  Google Scholar 

  20. E. R. Engdahl andC. P. Felix,Nature of travel-time anomalies at Lasa, J. Geophys. Res.76 (1971), 2706.

    Article  Google Scholar 

  21. P. R. Farnham, R. L. Sax, E. F. Chiburis andE. A. Flinn,P-wave parameters measured at the Montana Lasa, Seismic Data Lab. Rep. 217, Teledyne, Inc., Alexandria, Va. (1968), 13 pp.

    Google Scholar 

  22. B. S. Gopalakrishnan,P wave velocities in the mantle below 700 km, Geophys. J. R. Astr. Soc.17 (1969), 405.

    Google Scholar 

  23. R. J. Greenfield andR. M. Sheppard,The Moho depth variations under the LASA and their effect on dt/dΔ measurements, Bull. Seism. Soc. Am.59 (1969), 409.

    Google Scholar 

  24. B. Gutenberg,The propagation of the longitudinal waves produced by the Long Beach earthquake, Gerl. Beitr. Geophys.41 (1934), 114.

    Google Scholar 

  25. A. L. Hales, J. R. Cleary andJ. L. Roberts,Velocity distribution in the lower mantle, Bull. Seism. Soc. Am.58 (1968), 1975.

    Google Scholar 

  26. E. Herrin, E. P. Arnold, B. A. Bolt, G. E. Clawson, E. R. Engdahl, H. W. Freedman, D. W. Gordon, A. L. Hales, J. L. Lobdell, O. Nuttli, C. Romney, J. Taggart andW. Tucker,1968 seismological tables for P phases, Bull. Seism. Soc. Am.58 (1968), 1193.

    Google Scholar 

  27. J. H. Hodgson andR. S. Storey,Tables extending Byerly’s fault-plane techniques to earthquakes of any focal depth, Bull. Seism. Soc. Am.43 (1953), 49.

    Google Scholar 

  28. E. S. Husebye,Correction analysis of Jeffreys-Bullen travel time tables, Bull. Seism. Soc. Am.55 (1965), 1023.

    Google Scholar 

  29. E. S. Husebye,Seismic arrays and seismology, Acta Univ. Ups., Abstr. Uppsala Dissert. Fac. Sci.223 (1972), 13 pp.

  30. E. S. Husebye, R. Kanestrøm andR. Rud,Observations of vertical and lateral P-velocity anomalies in the Earth’s mantle using the Fennoscandian continental array, Geophys. J. R. Astr. Soc.25 (1971), 3.

    Google Scholar 

  31. E. Husebye andR. Madariaga,The origin of precursors to core waves, Bull. Seism. Soc. Am.60 (1970), 939.

    Google Scholar 

  32. H. M. Iyer,Variation of apparent velocity of teleseismic P waves across the Large-Aperture Seismic Array, Montana, J. Geophys. Res.76 (1971), 8554.

    Article  Google Scholar 

  33. H. M. Iyer andJ. H. Healy,Teleseismic residuals at the LASA-USCGS extended array and their interpretation in terms of crust and upper mantle structure, J. Geophys. Res.77 (1972), 1503.

    Article  Google Scholar 

  34. H. Jeffreys,The times of the core waves, 2, Mon. Not. R. Astr. Soc., Geophys., Suppl.4 (1939), 594.

    Google Scholar 

  35. H. Jeffreys andK. E. Bullen,Seismological Tables, Brit. Assoc. Adv. Sci., Gray Milne Trust, London (1967), 50 pp.

  36. L. R. Johnson,Array measurements of P velocities in the upper mantle, J. Geophys. Res.72 (1967), 6309.

    Article  Google Scholar 

  37. L. R. Johnson,Array measurements of P velocities in the lower mantle, Bull. Seism. Soc. Am.59 (1969), 973.

    Google Scholar 

  38. H. Kanamori,Upper mantle structure from apparent velocities of P-waves recorded at Wakayama micro-earthquake observatory, Bull. Earthq. Res. Inst.45 (1967), 657.

    Google Scholar 

  39. R. Kanestrøm,Upper mantle structure of northern Europe from apparent velocities of P waves, Geophysica (Helsinki)11 (1971), 241.

    Google Scholar 

  40. R. Kanestrøm andK. Haugland,Crustal structure in southeastern Norway from seismic refraction measurements, Seism. Obs., Bergen, Sci. Rep. No. 5 (1971), 71 pp.

  41. M. Niazi andD. L. Anderson,Upper mantle structure of western North America from apparent velocities of P waves, J. Geophys. Res.70 (1965), 4633.

    Article  Google Scholar 

  42. G. Payo Subiza andM. Båth,Core phases and the inner core boundary, Geophys. J. R. Astr. Soc.8 (1964), 496.

    Google Scholar 

  43. M. Shimshoni,The times of PKP and their depth allowances, Geophys. J. R. Astr. Soc.13 (1967), 471.

    Google Scholar 

  44. D. W. Simpson, C. Wright andJ. R. Cleary,Double discontinuity in the upper mantle, Nature Phys. Sci.231 (1971), 201.

    Article  Google Scholar 

  45. M. N. Toksöz, M. A. Chinnery andD. L. Anderson,Inhomogeneities in the Earth’s mantle, Geophys. J. R. Astr. Soc.13 (1967), 31.

    Google Scholar 

  46. J. R. Truscott,The Eskdalemuir seismological station, Geophys. J. R. Astr. Soc.9 (1964), 59.

    Google Scholar 

  47. L. P. Vinnik, A. A. Lukk andA. V. Nikolaev,Inhomogeneities in the lower mantle, Phys. Earth and Planet. Interiors5 (1972), 328.

    Article  Google Scholar 

  48. L. P. Vinnik andA. V. Nikolayev (Nikolaev),The velocity profile of the lower mantle from direct measurements of dt/dΔ, Bull. (Izv.) Acad. Sci. USSR, Earth Phys.11 (1970), 699 (English), 24 (Russian).

    Google Scholar 

  49. D. H. Weichert,Upper mantle structure under the Churchill Province of the Canadian Shield, east of the Yellowknife seismic array, J. Phys. Earth16 (1968), 93.

    Google Scholar 

  50. C. Wright andJ. R. Cleary,P wave travel-time gradient measurements for the Warramunga seismic array and lower mantle structure, Phys. Earth and Planet. Interiors5 (1972), 213.

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Seismological Institute, Box 517, S-751 20, Uppsala 1, Sweden

    R. James Brown

Authors
  1. R. James Brown
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Brown, R.J. Slowness and azimuth at the Uppsala array. PAGEOPH 109, 1623–1637 (1973). https://doi.org/10.1007/BF00876089

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00876089

Keywords

Search

Navigation