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High-resolution seismic constraints on flow dynamics in the oceanic asthenosphere

Nature volume 535, pages 538–541 (2016)Cite this article

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Abstract

Convective flow in the mantle and the motions of tectonic plates produce deformation of Earth’s interior, and the rock fabric produced by this deformation can be discerned using the anisotropy of the seismic wavespeed1,2,3. This deformation is commonly inferred close to lithospheric boundaries beneath the ocean in the uppermost mantle, including near seafloor-spreading centres as new plates are formed via corner flow4, and within a weak asthenosphere that lubricates large-scale plate-driven flow and accommodates smaller-scale convection5,6. Seismic models of oceanic upper mantle differ as to the relative importance of these deformation processes: seafloor-spreading fabric is very strong just beneath the crust–mantle boundary (the Mohorovičić discontinuity, or Moho) at relatively local scales7,8, but at the global and ocean-basin scales, oceanic lithosphere typically appears weakly anisotropic when compared to the asthenosphere9,10. Here we use Rayleigh waves, recorded across an ocean-bottom seismograph array in the central Pacific Ocean (the NoMelt Experiment), to provide unique localized constraints on seismic anisotropy within the oceanic lithosphere–asthenosphere system in the middle of a plate. We find that azimuthal anisotropy is strongest within the high-seismic-velocity lid, with the fast direction coincident with seafloor spreading. A minimum in the magnitude of azimuthal anisotropy occurs within the middle of the seismic low-velocity zone, and then increases with depth below the weakest portion of the asthenosphere. At no depth does the fast direction correlate with the apparent plate motion. Our results suggest that the highest strain deformation in the shallow oceanic mantle occurs during corner flow at the ridge axis, and via pressure-driven or buoyancy-driven flow within the asthenosphere. Shear associated with motion of the plate over the underlying asthenosphere, if present, is weak compared to these other processes.

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Figure 1: Layout of NoMelt deployment on a bathymetric map of the central Pacific, with seafloor age (in millions of years) shown as white contours.
Figure 2: Examples of the 2θ azimuthal variation of phase velocity measurements at different periods.
Figure 3: Shear velocity and azimuthal anisotropy models in the upper mantle beneath NoMelt.
Figure 4: Schematic of proposed models for azimuthal anisotropy beneath the NoMelt experiment.

References

  1. Hess, H. H. Seismic anisotropy of the uppermost mantle under oceans. Nature 203, 629–631 (1964)

    Article  ADS  Google Scholar 

  2. Forsyth, D. W. The early structural evolution and anisotropy of the oceanic upper mantle. Geophys. J. Int. 43, 103–162 (1975)

    Article  ADS  Google Scholar 

  3. Montagner, J. P. Upper mantle low anisotropy channels below the Pacific Plate. Earth Planet. Sci. Lett. 202, 263–274 (2002)

    Article  CAS  ADS  Google Scholar 

  4. Blackman, D. K. & Kendall, J. M. Seismic anisotropy in the upper mantle 2. Predictions for current plate boundary flow models. Geochem. Geophys. Geosyst. 3, 8602 (2002)

    ADS  Google Scholar 

  5. Phipps Morgan, J., Morgan, W. J., Zhang, Y.-S. & Smith, W. H. F. Observational hints for a plume-fed, suboceanic asthenosphere and its role in mantle convection. J. Geophys. Res. 100, 12753–12767 (1995)

    Article  ADS  Google Scholar 

  6. Agrusta, R. et al. Small-scale convection in a plume-fed low-viscosity layer beneath a moving plate. Geophys. J. Int. 194, 591–610 (2013)

    Article  ADS  Google Scholar 

  7. Raitt, R. W., Shor, G. G., Francis, T. J. G. & Morris, G. B. Anisotropy of the Pacific upper mantle. J. Geophys. Res. Solid Earth 74, 3095–3109 (1969)

    Article  Google Scholar 

  8. Gaherty, J. B., Lizarralde, D., Collins, J. A., Hirth, G. & Kim, S. Mantle deformation during slow seafloor spreading constrained by observations of seismic anisotropy in the western Atlantic. Earth Planet. Sci. Lett. 228, 255–265 (2004)

    Article  CAS  ADS  Google Scholar 

  9. Beghein, C., Yuan, K., Schmerr, N. & Xing, Z. Changes in seismic anisotropy shed light on the nature of the Gutenberg discontinuity. Science 343, 1237–1240 (2014)

    Article  CAS  ADS  PubMed  Google Scholar 

  10. Burgos, G. et al. Oceanic lithosphere-asthenosphere boundary from surface wave dispersion data. J. Geophys. Res. Solid Earth 119, 1079–1093 (2014)

    Article  ADS  Google Scholar 

  11. Montagner, J.-P. & Nataf, H.-C. Vectorial tomography—I. Theory. Geophys. J. Int. 94, 295–307 (1988)

    Article  ADS  MATH  Google Scholar 

  12. Tan, Y. & Helmberger, D. V. Trans-Pacific upper mantle shear velocity structure. J. Geophys. Res. 112, B08301 (2007)

    ADS  Google Scholar 

  13. Nishimura, C. E. & Forsyth, D. W. The anisotropic structure of the upper mantle in the Pacific. Geophys. J. Int. 96, 203–229 (1989)

    Article  ADS  Google Scholar 

  14. Sarafian, E. et al. The electrical structure of the central Pacific upper mantle constrained by the NoMelt experiment. Geochem. Geophys. Geosyst. 16, 1115–1132 (2015)

    Article  CAS  ADS  Google Scholar 

  15. Jackson, I. & Faul, U. H. Grainsize-sensitive viscoelastic relaxation in olivine: towards a robust laboratory-based model for seismological application. Phys. Earth Planet. Inter. 183, 151–163 (2010)

    Article  ADS  Google Scholar 

  16. Hirth, G. & Kohlstedt, D. L. Water in the oceanic upper mantle: implications for rheology, melt extraction and the evolution of the lithosphere. Earth Planet. Sci. Lett. 144, 93–108 (1996)

    Article  CAS  ADS  Google Scholar 

  17. Nicolas, A., Ceuleneer, G., Boudier, F. & Misseri, M. Structural mapping in the Oman ophiolites: mantle diapirism along an oceanic ridge. Tectonophysics 151, 27–56 (1988)

    Article  ADS  Google Scholar 

  18. Ismaïl, W. B. & Mainprice, D. An olivine fabric database: an overview of upper mantle fabrics and seismic anisotropy. Tectonophysics 296, 145–157 (1998)

    Article  ADS  Google Scholar 

  19. Shearer, P. & Orcutt, J. Anisotropy in the oceanic lithosphere — theory and observations from the Ngendei seismic refraction experiment in the south-west Pacific. Geophys. J. R. Astron. Soc. 80, 493–526 (1985)

    Article  ADS  Google Scholar 

  20. Maggi, A., Debayle, E., Priestley, K. & Barruol, G. Azimuthal anisotropy of the Pacific region. Earth Planet. Sci. Lett. 250, 53–71 (2006)

    Article  CAS  ADS  Google Scholar 

  21. Debayle, E. & Ricard, Y. Seismic observations of large-scale deformation at the bottom of fast-moving plates. Earth Planet. Sci. Lett. 376, 165–177 (2013)

    Article  CAS  ADS  Google Scholar 

  22. Conrad, C. P. & Behn, M. D. Constraints on lithosphere net rotation and asthenospheric viscosity from global mantle flow models and seismic anisotropy. Geochem. Geophys. Geosyst. 11, Q05W05 (2010)

    Article  Google Scholar 

  23. Becker, T. W., Conrad, C. P., Schaeffer, A. J. & Lebedev, S. Origin of azimuthal seismic anisotropy in oceanic plates and mantle. Earth Planet. Sci. Lett. 401, 236–250 (2014)

    Article  CAS  ADS  Google Scholar 

  24. Silver, P. G. & Holt, W. E. The mantle flow field beneath western North America. Science 295, 1054–1057 (2002)

    Article  CAS  ADS  PubMed  Google Scholar 

  25. Becker, T. W. On the effect of temperature and strain-rate dependent viscosity on global mantle flow, net rotation, and plate-driving forces. Geophys. J. Int. 167, 943–957 (2006)

    Article  ADS  Google Scholar 

  26. Buck, W. R., Small, C. & Ryan, W. B. F. Constraints on asthenospheric flow from the depths of oceanic spreading centers: the East Pacific Rise and the Australian-Antarctic discordance. Geochem. Geophys. Geosyst. 10, Q09007 (2009)

    Article  ADS  Google Scholar 

  27. Höink, T., Lenardic, A. & Richards, M. Depth-dependent viscosity and mantle stress amplification: implications for the role of the asthenosphere in maintaining plate tectonics. Geophys. J. Int. 191, 30–41 (2012)

    Article  ADS  Google Scholar 

  28. Parsons, B. & McKenzie, D. Mantle convection and the thermal structure of the plates. J. Geophys. Res. Solid Earth 83, 4485–4496 (1978)

    Article  Google Scholar 

  29. Haxby, W. F. & Weissel, J. K. Evidence for small-scale mantle convection from Seasat altimeter data. J. Geophys. Res. Solid Earth 91, 3507–3520 (1986)

    Article  Google Scholar 

  30. Richter, F. M. & Parsons, B. On the interaction of two scales of convection in the mantle. J. Geophys. Res. Solid Earth 80, 2529–2541 (1975)

    Article  Google Scholar 

  31. French, S., Lekic, V. & Romanowicz, B. Waveform tomography reveals channeled flow at the base of the oceanic asthenosphere. Science 342, 227–230 (2013)

    Article  CAS  ADS  PubMed  Google Scholar 

  32. Sandwell, D. T., Müller, R. D., Smith, W. H. F., Garcia, E. & Francis, R. New global marine gravity model from CryoSat-2 and Jason-1 reveals buried tectonic structure. Science 346, 65–67 (2014)

    Article  CAS  ADS  PubMed  Google Scholar 

  33. Argus, D. F. & Gordon, R. G. No-net-rotation model of current plate velocities incorporating plate motion model NUVEL-1. Geophys. Res. Lett. 18, 2039–2042 (1991)

    Article  ADS  Google Scholar 

  34. Webb, S. C. & Crawford, W. C. Long-period seafloor seismology and deformation under ocean waves. Bull. Seismol. Soc. Am. 89, 1535–1542 (1999)

    Google Scholar 

  35. Crawford, W. C. & Webb, S. C. Identifying and removing tilt noise from low-frequency (<0.1 Hz) seafloor vertical seismic data. Bull. Seismol. Soc. Am. 90, 952–963 (2000)

    Article  Google Scholar 

  36. Bell, S. W., Forsyth, D. W. & Ruan, Y. Removing noise from the vertical component records of ocean-bottom seismometers: results from year one of the Cascadia Initiative. Bull. Seismol. Soc. Am. 105, 300–313 (2015)

    Article  Google Scholar 

  37. Jin, G. & Gaherty, J. B. Surface wave phase-velocity tomography based on multichannel cross-correlation. Geophys. J. Int. 201, 1383–1398 (2015)

    Article  ADS  Google Scholar 

  38. Lin, F.-C., Ritzwoller, M. H. & Snieder, R. Eikonal tomography: surface wave tomography by phase front tracking across a regional broad-band seismic array. Geophys. J. Int. 177, 1091–1110 (2009)

    Article  ADS  Google Scholar 

  39. Smith, M. L. & Dahlen, F. A. The azimuthal dependence of Love and Rayleigh wave propagation in a slightly anisotropic medium. J. Geophys. Res. Solid Earth 78, 3321–3333 (1973)

    Article  Google Scholar 

  40. Menke, W. & Jin, G. Waveform fitting of cross spectra to determine phase velocity using Aki’s formula. Bull. Seismol. Soc. Am. 105, 1619–1627 (2015)

    Article  Google Scholar 

  41. Herrmann, R. B. Computer programs in seismology: an evolving tool for instruction and research. Seismol. Res. Lett. 84, 1081–1088 (2013)

    Article  Google Scholar 

  42. Montagner, J.-P. & Nataf, H.-C. A simple method for inverting the azimuthal anisotropy of surface waves. J. Geophys. Res. Solid Earth 91, 511–520 (1986)

    Article  Google Scholar 

  43. Zhu, H. & Tromp, J. Mapping tectonic deformation in the crust and upper mantle beneath Europe and the North Atlantic Ocean. Science 341, 871–875 (2013)

    Article  CAS  ADS  PubMed  Google Scholar 

  44. Montagner, J. P. & Tanimoto, T. Global upper mantle tomography of seismic velocities and anisotropies. J. Geophys. Res. 96, 20337–20351 (1991)

    Article  ADS  Google Scholar 

  45. Peterson, J. Observation and modeling of seismic background noise. Open-File Report No. 93-322 (US Department of Interior Geological Survey, 1993)

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Acknowledgements

We thank the scientific party, captain, crews, and technical teams of RV Marcus G. Langseth and RV Melville for work that made this study possible. The OBS were provided and supported by Scripps Institution of Oceanography’s facility as part of the US Ocean Bottom Seismograph Instrument Pool (http://www.obsip.org). This work was funded by the US National Science Foundation. P.-Y.P.L. thanks the Institute of Earth Science, Academia Sinica, Taipei, Taiwan and Institute of Undersea Technology, National Sun Yat-sen University, Kaohsiung, Taiwan for support during completion of this work.

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Author notes

  1. Pei-Ying Patty Lin, John A. Collins & Daniel Lizarralde

    Present address: Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA

  2. Rob. L. Evans

    Present address: †Present address: Taiwan Ocean Research Institute, National Applied Research Laboratories, Kaohsiung, Taiwan (P.-Y.P.L.).,

Authors and Affiliations

  1. Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York, USA

    Pei-Ying Patty Lin, James B. Gaherty & Ge Jin

  2. Geological Sciences Department, Brown University, Providence, Rhode Island, USA

    Greg Hirth

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Contributions

P.-Y.P.L. and J.B.G. collaborated in developing the concept of this paper and writing the first draft. All authors contributed to the scientific discussion, including presentation of results, interpretation, and implications.

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Correspondence to Pei-Ying Patty Lin.

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Extended data figures and tables

Extended Data Figure 1 Power spectral densities (PSDs) of raw, tilt and compliance noise-removed seismograms.

The PSD values are calculated from vertical data recorded by one NoMelt station, B13, located at 9.25° N, 145.55° W). The black curves show the spectrum of the raw vertical component. The red and blue curves show the spectrum after removing the tilt noise and compliance noise, respectively. The PSD is reported in decibels (dB) referenced to 10log[AAS (m−2 s−4 Hz−1)], where AAS is the acceleration-amplitude spectrum. The new high- and low-noise models of ref. 45, NHNM and NLNM (thin dashed lines), are shown as references.

Extended Data Figure 2 Rayleigh waveforms recorded by NoMelt.

a, Broadband vertical-component seismograms filtered in the 20–100-s period band from an event (green circle) in the southwestern Pacific (see inset map). The red inverted triangle denotes the NoMelt location. b, Ambient noise cross-correlation waveforms, filtered between 10 s and 25 s in the time domain.

Extended Data Figure 3 Shallow-teleseismic event distribution.

19 events (red stars) with high-quality Rayleigh waves were recorded during NoMelt one-year deployment. White lines represent the corresponding great-circle paths. Grey contours show the epicentral distances at 10° intervals.

Extended Data Figure 4 Forward calculations.

The upper panels show four input models of G parameters (green solid, magenta solid, orange solid and blue dashed-dotted lines). The lower panels show the forward-calculated peak-to-peak amplitude A and fast direction ϕ as functions of period from the four models. Our observations are shown as blue circle symbols with error bars of 1 s.d. as references. The black and grey dashed lines indicate the orientation of the FSD and apparent plate motion (APM) at the NoMelt location.

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Lin, PY., Gaherty, J., Jin, G. et al. High-resolution seismic constraints on flow dynamics in the oceanic asthenosphere. Nature 535, 538–541 (2016). https://doi.org/10.1038/nature18012

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