Skip to main content

Advertisement

Determination of the absolute depths of the mantle transition zone discontinuities beneath China: Effect of stagnant slabs on transition zone discontinuities

Article metrics

  • 304 Accesses

  • 24 Citations

Abstract

Broadband seismic waveform data are stacked to investigate the mantle discontinuities beneath a station. A polarized filter is devised to remove pseudo-signals in the stacked traces, which might be otherwise misinterpreted as a discontinuity. The depth of a mantle discontinuity determined in previous studies depends on the reference model. We suggest the use of data sets which have a range of epicentral distances to the investigated station. The observed travel time of the P-to-S converted phases as a function of epicentral distance can be used to constrain the proper reference model. When the technique is applied to real data, we can determine the absolute depth of a discontinuity with an accuracy of approximately ±10 km. The method is applied to the broadband data of the CDSN stations. There is no significant depression observed for any of the stations except BJI, implying that the lateral scale of the trough in the ‘660-km’ discontinuity under northeast China is smaller than suggested in previous SS precursors studies. Beneath station BJI, the ‘410-km’ and ‘660-km’ discontinuities are elevated 10 km and depressed 30 km, respectively, resulting in an extremely thick transition zone. This may be attributed to the cold pacific plate that exists in the transition zone of the same region. Meanwhile, at station MDJ, where the subducted pacific plate is also found in the mantle transition zone, a multiple-discontinuity structure is observed rather than a depressed ‘660-km’ discontinuity. At station SSE, there is no depression of the ‘660-km’ discontinuity, suggesting that there is no significant difference of temperature at depths around 660 km between SSE and the average mantle.

References

  1. Efron, E. and R. Tibshirani, Bootstrap methods for standard errors, confidence interval, and other measures of statistical accuracy, Statis. Sci., 1, 54–77, 1986.

  2. Flanagan, M. P. and P. M. Shearer, Glabal mapping of the topography on the transition zone velocity discontinuities by stacking SS precursors, J. Geophys. Res., 103, 2673–2692, 1998.

  3. Fukao, Y., M. Obayashi, M. Inoue, and M. Nenbai, Subducting slabs stagnant in the mantle transition zone, J. Geophys. Res., 97, 4809–4822, 1992.

  4. Grand, S. P. and D. V. Helmberger, Upper mantle shear structure of the North America, Geophys. J. R. Astr. Soc., 76, 399–438, 1984.

  5. Haskell, N. A., Crustal reflections of the plane P and SV waves, J. Geophys. Res., 67, 4751–4767, 1962.

  6. Kennett, B. L. N. and E. R. Engdahl, Travel times for global earthquake location and phase identification, Geophys. J. Int., 105, 429–465, 1991.

  7. Koch, M., Bootstrap inversion for vertical and lateral variations of the S wave structure and the vp /vs -ratio from shallow earthquakes in the Rhinergraben seismic zone, Germany, Tectonophysics, 210, 91–115, 1992.

  8. Neele, F., H. De Regt, and J. VanDecar, Gross errors in uppermantle dis-continuity topography from underside reflection data, Geophys. J. Int., 129, 194–204, 1997.

  9. Niu, F. and H. Kawakatsu, Direct evidence for the undulation of the 660-km discontinuity beneath Tonga: Comparison of Japan and California array data, Geophys. Res. Lett., 22, 531–534, 1995.

  10. Niu, F. and H. Kawakatsu, Complex structure of the mantle discontinuities at the tip of the subducting slab beneath the northeast China: a preliminary investigation of broadband receiver functions, J. Phys. Earth, 44, 701–711, 1996.

  11. Petersen, N., J. Gossler, R. Kind, K. Stammler, and L. Vinnik, Precursors to SS and structure of transition zone of the north-western Pacific, Geophys. Res. Lett., 20, 281–284, 1993.

  12. Revenaugh, J. and S. A. Sipkin, Mantle discontinuity structure beneath China, J. Geophys. Res., 99, 21911–21927, 1994.

  13. Richards, M. A. and C. W. Wicks, Jr., S-P conversion from the transition zone beneath Tonga and the nature of the 670 km discontinuity, Geophys. J. Int., 101, 1–35, 1990.

  14. Sakurai, T., M. Obayashi, and Y. Fukao, Tomographic image of slab and mantle plume, Program and Abstracts, Seism. Soc. Japan, 1, 624, 1995 (in Japanese).

  15. Shearer, P. M., Global mapping of upper mantle reflectors from long-period SS precursors, Geophys. J. Int., 115, 878–904, 1993.

  16. Shearer, P. M. and T. G. Masters, Global mapping of topography on the 660 km discontinuity, Nature, 355, 791–796, 1992.

  17. Tajima, F., Y. Fukao, M. Obayashi, and T. Sakurai, Evaluation of slab images in the northwestern Pacific, Earth Planets Space, 50, this issue, 953–964, 1998.

  18. Vacher, P., A. Mocquet, and C. Sotin, Computation of seismic profiles from mineral physics: the importance of the non-olivine components for explaining the 660 km depth discontinuity, Phys. Earth Planet. Inter., 106, 277–300, 1998.

  19. van der Hilst, R., R. Engdahl, W. Spakman, and G. Nolet, Tomographic imaging of subducted lithosphere below north-west Pacific island arcs, Nature, 353, 37–43, 1991.

  20. Vidale, J. E. and H. M. Benz, Uppermantle seismic discontinuities and the thermal structure of subduction zones, Nature, 356, 678–682, 1992.

  21. Vinnik, L. P., Detection of waves converted from P to SV in mantle, Phys. Earth Planet. Inter., 15, 39–45, 1976.

  22. Vinnik, L. P., G. Kosarev, and N. Petersen, Mantle transition zone beneath Eurasia, Geophys. Res. Lett., 23, 1485–1488, 1996.

  23. Walck, M. C., The P-wave upper mantle shear structure beneath an active spreading center: the Gulf of California, Geophys. J. R. Astr. Soc., 76, 697–723, 1984.

  24. Wicks, C. W., Jr. and M. A. Richards, A detailed map of the 660-kilometer discontinuity beneath the Izu-Bonin subduction zone, Science, 261, 1424–1427, 1993.

  25. Zhou, H. W. and R. W. Clayton, P and S wave travel time inversions for subducting slab under the island arcs of Northeast Pacific, J. Geophys. Res., 95, 6829–6851, 1990.

Download references

Author information

Correspondence to Fenglin Niu.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Niu, F., Kawakatsu, H. Determination of the absolute depths of the mantle transition zone discontinuities beneath China: Effect of stagnant slabs on transition zone discontinuities. Earth Planet Sp 50, 965–975 (1998) doi:10.1186/BF03352191

Download citation

Keywords

  • Transition Zone
  • Reference Model
  • Epicentral Distance
  • Converted Wave
  • Mantle Transition Zone