pure and applied geophysics

, Volume 109, Issue 1, pp 1623–1637 | Cite as

Slowness and azimuth at the Uppsala array

Part 2: Structural Studies
  • R. James Brown


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.


Azimuth Lower Mantle Apparent Velocity Uppermost Mantle Mantle Structure 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. [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. [2]
    M. Båth,Methods to improve seismograph data, Scientia102 (1967), 304 (English), 146 (French).Google Scholar
  3. [3]
    M. Båth andA. Lopez Arroyo,Pa and Sa waves and the upper mantle, Geofisica Pura e Appl.56 (1963), 67.CrossRefGoogle Scholar
  4. [4]
    B. A. Bolt,The velocity of seismic waves near the Earth’s center, Bull. Seism. Soc. Am.54 (1964), 191.Google Scholar
  5. [5]
    B. A. Bolt,Estimation of PKP travel times, Bull. Seism. Soc. Am.58 (1968), 1305.Google Scholar
  6. [6]
    H. Borg andM. Båth,The Uppsala seismograph array station, Pure and Appl. Geophys.89 (1971), 19.CrossRefGoogle Scholar
  7. [7]
    R. J. Brown,Lateral inhomogeneity in the crust and upper mantle from P-wave amplitudes, Pure and Appl. Geophys. (in press, 1972).Google Scholar
  8. [8]
    R. J. Brown,Azimuthally varying P-wave travel-time residuals in Fennoscandia and lateral inhomogeneity, Pure and Appl. Geophys. (in press, 1973).Google Scholar
  9. [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).Google Scholar
  10. [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.CrossRefGoogle Scholar
  11. [11]
    G. G. R. Buchbinder,Distance corrections for deep focus earthquakes, Geophys. J. R. Astr. Soc.17 (1969), 195.Google Scholar
  12. [12]
    M. A. Chinnery,Velocity anomalies in the lower mantle, Phys. Earth and Planet. Interiors2 (1969), 1.CrossRefGoogle Scholar
  13. [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. [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. [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. [16]
    D. J. Corbishley,Structure under seismic arrays, Geophys. J. R. Astr. Soc.21 (1970), 415.Google Scholar
  17. [17]
    D. J. Doornbos andE. S. Husebye,Array analysis of PKP phases and their precursors, in a NORSAR report (in press, 1972).Google Scholar
  18. [18]
    M. A. Enayatollah,Travel times of P-waves for the Swedish-Finnish seismograph network, Pure and Appl. Geophys.94 (1972), 101.CrossRefGoogle Scholar
  19. [19]
    M. A. Enayatollah,Continental-array measurements of P-wave velocities in the mantle, Pure and Appl. Geophys.94 (1972), 136.CrossRefGoogle Scholar
  20. [20]
    E. R. Engdahl andC. P. Felix,Nature of travel-time anomalies at Lasa, J. Geophys. Res.76 (1971), 2706.CrossRefGoogle Scholar
  21. [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. [22]
    B. S. Gopalakrishnan,P wave velocities in the mantle below 700 km, Geophys. J. R. Astr. Soc.17 (1969), 405.Google Scholar
  23. [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. [24]
    B. Gutenberg,The propagation of the longitudinal waves produced by the Long Beach earthquake, Gerl. Beitr. Geophys.41 (1934), 114.Google Scholar
  25. [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. [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. [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. [28]
    E. S. Husebye,Correction analysis of Jeffreys-Bullen travel time tables, Bull. Seism. Soc. Am.55 (1965), 1023.Google Scholar
  29. [29]
    E. S. Husebye,Seismic arrays and seismology, Acta Univ. Ups., Abstr. Uppsala Dissert. Fac. Sci.223 (1972), 13 pp.Google Scholar
  30. [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. [31]
    E. Husebye andR. Madariaga,The origin of precursors to core waves, Bull. Seism. Soc. Am.60 (1970), 939.Google Scholar
  32. [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.CrossRefGoogle Scholar
  33. [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.CrossRefGoogle Scholar
  34. [34]
    H. Jeffreys,The times of the core waves, 2, Mon. Not. R. Astr. Soc., Geophys., Suppl.4 (1939), 594.Google Scholar
  35. [35]
    H. Jeffreys andK. E. Bullen,Seismological Tables, Brit. Assoc. Adv. Sci., Gray Milne Trust, London (1967), 50 pp.Google Scholar
  36. [36]
    L. R. Johnson,Array measurements of P velocities in the upper mantle, J. Geophys. Res.72 (1967), 6309.CrossRefGoogle Scholar
  37. [37]
    L. R. Johnson,Array measurements of P velocities in the lower mantle, Bull. Seism. Soc. Am.59 (1969), 973.Google Scholar
  38. [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. [39]
    R. Kanestrøm,Upper mantle structure of northern Europe from apparent velocities of P waves, Geophysica (Helsinki)11 (1971), 241.Google Scholar
  40. [40]
    R. Kanestrøm andK. Haugland,Crustal structure in southeastern Norway from seismic refraction measurements, Seism. Obs., Bergen, Sci. Rep. No. 5 (1971), 71 pp.Google Scholar
  41. [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.CrossRefGoogle Scholar
  42. [42]
    G. Payo Subiza andM. Båth,Core phases and the inner core boundary, Geophys. J. R. Astr. Soc.8 (1964), 496.Google Scholar
  43. [43]
    M. Shimshoni,The times of PKP and their depth allowances, Geophys. J. R. Astr. Soc.13 (1967), 471.Google Scholar
  44. [44]
    D. W. Simpson, C. Wright andJ. R. Cleary,Double discontinuity in the upper mantle, Nature Phys. Sci.231 (1971), 201.CrossRefGoogle Scholar
  45. [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. [46]
    J. R. Truscott,The Eskdalemuir seismological station, Geophys. J. R. Astr. Soc.9 (1964), 59.Google Scholar
  47. [47]
    L. P. Vinnik, A. A. Lukk andA. V. Nikolaev,Inhomogeneities in the lower mantle, Phys. Earth and Planet. Interiors5 (1972), 328.CrossRefGoogle Scholar
  48. [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. [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. [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.CrossRefGoogle Scholar

Copyright information

© Birkhäuser-Verlag 1973

Authors and Affiliations

  • R. James Brown
    • 1
  1. 1.Seismological InstituteUppsala 1Sweden

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