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pure and applied geophysics

, Volume 132, Issue 1–2, pp 331–362 | Cite as

Q measurements for PhaseX overtones

  • Emile A. Okal
  • Bong-Gon Jo
Article

Abstract

Linear stacking procedures are used to retrieve the attenuation of 91 modes belonging to the 3rd, 4th and 5th Rayleigh overtones branches in the 80–160 s period range, and contributing to the so-called “PhaseX” wave group. Our data show in general slightly less attenuation than expected from available models. Data space inversion shows that, when combined with previously measured fundamental modeQ's, this new dataset improves resolution significantly in the 1000–2000 km depth range. Based on this remark, we carry out a number of parameter space inversions. Our results suggest a narrow (80–200 km) zone of high attenuation (Qμ=75–90), low attenuation in the intermediate mantle (670–1500 km); (Qμ≈350), and lower values in the deeper mantle (Qμ≈200).

Key words

Mantle attenuation spheroidal overtones 

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References

  1. Aki,K., andRichards, P. G.,Quantitative Seismology (San Francisco, W. H. Freeman and Co. 1980), 932 pp.Google Scholar
  2. Alsop, L. E., Sutton, G. H., andEwing, M. (1961),Measurement of Q for Very Long Period Free Oscillations, J. Geophys. Res.66, 2911–2915.Google Scholar
  3. Anderson, D. L., andHart, R. S. (1978),Attenuation Models of the Earth, Phys. Earth Planet. Inter.16, 289–306.Google Scholar
  4. Backus, G., andGilbert, J. F. (1967),Numerical Applications of a Formalism for Geophysical Inverse Problems, Geophys. J. Roy. Astr. Soc.13, 247–276.Google Scholar
  5. Backus, G., andGilbert, J. F. (1968),The Resolving Power of Gross Earth Data, Geophys. J. Roy. Astr. Soc.16, 169–205.Google Scholar
  6. Buland, R. P., andGilbert, J. F. (1978),Improved Resolution of Complex Eigenfrequencies in Analytically Continued Seismic Spectra, Geophys., J. Roy. Astr. Soc.52, 457–470.Google Scholar
  7. Dahlen, F. A. (1975),The Correction of Great-circular Surface Wave Phase Velocity Measurements for the Rotation and Ellipticity of the Earth, J. Geophys. Res.80, 4895–4903.Google Scholar
  8. Dahlen, F. A. (1979),The Spectra of Unresolved Split Normal Mode Multiplets, Geophys. J. Roy. Astr. Soc.58, 1–33, 1979.Google Scholar
  9. Ding, X.-Y., andGrand, S. P. (1987),Q as a Function of Depth Beneath a Tectonically Active Area, Eos. Trans. Am. Geophys. Un.68, 1376 [abstract].Google Scholar
  10. Dratler, J., Farrell, W. E., Block, B., andGilbert, J. F. (1971),High-Q Overtone Modes of the Earth. Geophys. J. Roy. Astr. Soc.23, 399–410.Google Scholar
  11. Dziewonski, A. M., andAnderson, D. L. (1981),Preliminary Reference Earth Model, Phys. Earth Planet. Inter.25, 297–356.Google Scholar
  12. Dziewonski, A. M., andGilbert, J. F. (1973),Observations of Normal Modes from 84 Recordings of the Alaskan Earthquake of 1964 March 28.—II.: Further Remarks Based on New Spheroidal Overtone Data, Geophys. J. Roy. Astr. Soc.35, 401–437.Google Scholar
  13. Dziewonski, A. M., Friedman, A., Giardini, D., andWoodhouse, J. H. (1983a),Global Seismicity of 1982: Centroid-moment Tensor Solutions for 308 Earthquakes, Phys. Earth Planet. Inter.33, 76–90.Google Scholar
  14. Dziewonski, A. M., Franzen, J. E., andWoodhouse, J. H. (1983b),Centroid-moment Tensor Solutions for April–June, 1983, Phys. Earth Planet. Inter.33, 243–249.Google Scholar
  15. Fukao, Y., andSuda, N. (1987),Detection of Core Modes from the Earth's Free Oscillation and Structure of the Inner Core. Proc. XIXth Gen. Assemb. Intl. Un. Geod. Geophys., Vancouver, B.C., August 9–22, 1987.V.1, p. 5 [abstract].Google Scholar
  16. Geller, R. J., andStein, S. (1978),Time Domain Measurements of Attenuation of Fundamental Modes(oS6-oS28) for the 1977 Indonesian Earthquake, Bull. Seismol. Soc. Am.69, 1671–1691.Google Scholar
  17. Gilbert, J. F. (1971),Ranking and Winnowing Gross Earth Data for Inversion and Resolution, Geophys. J. Roy. Astr. Soc.23, 125–128, 1971.Google Scholar
  18. Hansen, R. A., andBolt, B. A. (1980),Variations Between Q Values Estimated from Damped Terrestrial Eigenvibrations, J. Geophys. Res.85, 5237–5243.Google Scholar
  19. Jo, B.-G.,Dispersion and Attenuation of Mantle Rayleigh Rayleigh Overtones, Ph.D. Dissertation (Yale University, New Haven 1986).Google Scholar
  20. Jobert, N. (1978),Contribution of Some Particularities in the Dispersion Curves to Numerical Seismograms Computed by Normal Modes. J. Comput. Phys.29, 404–411.Google Scholar
  21. Jobert, N., andRoult, G. (1976),Periods and Damping of Free Oscillations Observed in France after Sixteen Earthquakes, Geophys. J. Roy. Astr. Soc.45, 155–176.Google Scholar
  22. Jobert, N., Gaulon, R., Dieulin, A., andRoult, G. (1977),Sur des ondes à très longue période, caractéristiques du manteau supérieur, C. R. Acad. Sci. Paris, Sér. B285, 49–52.Google Scholar
  23. Kanamori, H., andAnderson, D. L. (1977),Importance of Physical Dispersion in Surface Wave and Free Oscillation Problems: Review, Rev. Geophys. Space Phys.15, 105–112.Google Scholar
  24. Kanamori, H., andCipar, J. J. (1974),Focal Process of the Great Chilean Earthquake, May 22, 1960, Phys. Earth Planet. Inter.9, 128–136.Google Scholar
  25. Kanamori, H., andGiven, J. W. (1982),Use of Long-period Surface Waves for Fast Determination of Earthquake Source Parameters; 2. Preliminary Determination of Source Mechanism of Large Earthquakes(Ms≥6.5) in 1980, Phys. Earth Planet. Inter.30, 260–268.Google Scholar
  26. Kanamori, H., andMiyamura, S. (1970),Seismometrical Re-evaluation of the Great Kanto Earthquake of September 1, 1923, Bull. Earthq. Res. Inst. Tokyo Univ.48, 115–125.Google Scholar
  27. Lanczos, C. Linear Differential Operators (Van Nostrand, London 1961).Google Scholar
  28. Masters, G., andGilbert, J. F. (1981),Structure of the Inner Core Inferred from Observations of its Spheroidal Shear Modes, Geophys. Res. Letts.8, 569–571.Google Scholar
  29. Masters, T. G., andGilbert, F. (1983),Attenuation in the Earth at Low Frequencies, Phil. Trans. Roy. Soc. London308A, 479–522.Google Scholar
  30. Mendiguren, J. A. (1973),Identification of Free Oscillation Spectral Peaks for the 1970 July 31, Colombian Deep Shock Using the Excitation Criterion, Geophys. J. Roy. Astr. Soc.33, 281–321.Google Scholar
  31. Mills, J. M., Jr., andHales, A. L. (1977),Great Circle Rayleigh Wave Attenuation and Group Velocity, Part I: Observations for Periods between 150 and 600 Seconds for 7 Great Circle Paths, Phys. Earth Planet. Inter.14, 109–119.Google Scholar
  32. Mills, J. M., Jr., andHales, A. L. (1978),Great Circle Rayleigh Wave Attenuation and Group Velocity. Part II: Observations for Periods between 50 and 200 Seconds for 9 Great Circle Paths, and Global Averages for Periods of 50 to 600 Seconds, Phys. Earth Planet. Inter.17, 209–231.Google Scholar
  33. Nakanishi, I. (1979),Attenuation of Multiple ScS Beneath the Japanese Arc, Phys. Earth Planet. Inter.19, 337–347.Google Scholar
  34. Nakanishi, I. (1981),Shear Velocity and Shear Attenuation Models Inverted from the World-wide and Pare-path Average Data of Mantle Rayleigh waves(0S25 to0S80) and Fundamental Spheroidal Modes (0S2-0S24), Geophys. J. Roy. Astr. Soc.66, 83–130.Google Scholar
  35. Ness, N. F., Harrison, J. C., andSlichter, L. B. (1961),Observations of the Free Oscillations of the Earth, J. Geophys. Res.66, 621–629.Google Scholar
  36. Nowroozi, A. A. (1974),Characteristic Periods and Q for Oscillations of the Earth Following an Intermediate Focus Earthquake, J. Phys. Earth22, 1–23.Google Scholar
  37. Okal, E. A. (1978),A Physical Calssification of the Earth's Spheroidal Modes, J. Phys. Earth26, 75–103.Google Scholar
  38. Okal, E. A. (1980),Overtone Q's from the IDA Network, Eos, Trans. Am. Geophys. Un.61, 1043 [abstract].Google Scholar
  39. Okal, E. A., andJo, B.-G. (1985),Stacking Investigations of Higher-order Mantle Rayleigh Waves, Geophys. Res. Letts.12, 421–424.Google Scholar
  40. Okal, E. A., andJo, B.-G. (1987),Stacking Investigations of the Dispersion of Higher Order Mantle Rayleigh Waves and Normal Modes, Phys. Earth Planet. Inter.47, 188–204.Google Scholar
  41. Okal, E. A., andStein, S. (1981),Measurement and Inversion of Overtones Spheroidal Q's from IDA Records, Eos, Trans. Am. Geophys. Un.62, 947 [abstract].Google Scholar
  42. Rees, B. A., andOkal, E. A. (1987),The Depth of the Deepest Historical Earthquakes, Pure Appl. Geophys.125, 699–715.Google Scholar
  43. Romanowicz, B. A., andGuillemant, P. (1984),An Experiment in the Retrieval of Depth and Source Mechanism of Large Earthquakes Using Very Long-period Wave Data, Bull. Seismol. Soc. Am.74, 417–437.Google Scholar
  44. Roult, G. (1974),Atténuation des ondes sismiques de très basse fréquence, Ann. Géophys.30, 141–167.Google Scholar
  45. Roult, G. (1975),Attenuation of Seismic Waves of Very Low Frequency, Phys. Earth Planet. Inter.10, 159–166.Google Scholar
  46. Sailor, R. V., andDziewonski, A. M. (1978),Measurements and Interpretation of Normal Mode Attenuation, Geophys. J. Roy. Astr. Soc.53, 559–581.Google Scholar
  47. Silver, P. G., andJordan, T. H. (1981),Fundamental Spheroidal Mode Observations of Aspherical Heterogeneity, Geophys. J. Roy. Astr. Soc.64, 605–634.Google Scholar
  48. Sipkin, S. A., andJordan, T. H. (1980),Regional Variation of Q ScS, Bull. Seismol. Soc. Am.70, 1071–1102.Google Scholar
  49. Sleep, N. H., Geller, R. J., andStein, S. (1981),A Constraint on the Earth's Lateral Heterogeneity from the Scattering of Spheroidal Mode Q−1 Measurements Bull. Seismol. Soc. Am.71, 183–197.Google Scholar
  50. Smith, S. W. (1972),The Anelasticity of the Mantle, Tectonophysics13, 601–622.Google Scholar
  51. Stein, S., andGeller, R. J. (1978),Attenuation Measurements of Split Normal Modes for the 1960 Chilean and 1964 Alaskan Earthquakes, Bull. Seismol. Soc. Am.68, 1595–1611.Google Scholar
  52. Stein, S., andNunn, J. A. (1981),Analysis of Split Normal Modes for the 1977 Indonesian Earthquake, Bull. Seismol. Soc. Am.71, 1031–1047.Google Scholar
  53. Stein, S., Mills, J. M., Jr., andGeller, R. J.,Q −1 models from data space inversion of fundamental spheroidal mode attenuation measurements, InAnelasticity of the Earth (eds. Stacey, F. D., Paterson, M. S., and Nicolas, A.) Geodynamics Series,4 (Am. Geophys. Un., Washington, D.C. 1981) pp. 39–53.Google Scholar
  54. Tanimoto, T. (1987),The Three-dimensional Shear Wave Structure in the Mantle by Overtone Waveform Inversion—I. Radical Seismogram Inversion, Geophys. J. Roy. Astr. Soc.49, 713–740.Google Scholar
  55. Wiggins, R. A. (1972),The General Linear Inverse Problem: Implications of Surface Waves and Free Oscillations for Earth Structure, Rev. Geophys. Space Phys.10, 251–285.Google Scholar
  56. Wiggins, R. A. (1976),A Fast, New Computational Algorithm for Free Oscillations and Surface Waves, Geophys. J. Roy. Astr. Soc.47, 135–150.Google Scholar
  57. Woodhouse, J. H., andDziewonski, A. M. (1984),Mapping the Upper Mantle: Three-dimensional Modeling of Earth Structure by Inversion of Seismic Data, J. Geophys. Res.89, 5953–5986.Google Scholar

Copyright information

© Birkhäuser Verlag 1990

Authors and Affiliations

  • Emile A. Okal
    • 1
  • Bong-Gon Jo
    • 1
  1. 1.Department of Geological SciencesNorthwestern UniversityEvanstonUSA

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