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Asthenosphere rheology inferred from observations of the 2012 Indian Ocean earthquake

Nature volume 538, pages 368–372 (2016)Cite this article

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Abstract

The concept of a weak asthenospheric layer underlying Earth’s mobile tectonic plates is fundamental to our understanding of mantle convection and plate tectonics. However, little is known about the mechanical properties of the asthenosphere (the part of the upper mantle below the lithosphere) underlying the oceanic crust, which covers about 60 per cent of Earth’s surface. Great earthquakes cause large coseismic crustal deformation in areas hundreds of kilometres away from and below the rupture area. Subsequent relaxation of the earthquake-induced stresses in the viscoelastic upper mantle leads to prolonged postseismic crustal deformation that may last several decades and can be recorded with geodetic methods1,2,3. The observed postseismic deformation helps us to understand the rheological properties of the upper mantle, but so far such measurements have been limited to continental-plate boundary zones. Here we consider the postseismic deformation of the very large (moment magnitude 8.6) 2012 Indian Ocean earthquake4,5,6 to provide by far the most direct constraint on the structure of oceanic mantle rheology. In the first three years after the Indian Ocean earthquake, 37 continuous Global Navigation Satellite Systems stations in the region underwent horizontal northeastward displacements of up to 17 centimetres in a direction similar to that of the coseismic offsets. However, a few stations close to the rupture area that had experienced subsidence of up to about 4 centimetres during the earthquake rose by nearly 7 centimetres after the earthquake. Our three-dimensional viscoelastic finite-element models of the post-earthquake deformation show that a thin (30–200 kilometres), low-viscosity (having a steady-state Maxwell viscosity of (0.5–10) × 1018 pascal seconds) asthenospheric layer beneath the elastic oceanic lithosphere is required to produce the observed postseismic uplift.

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Figure 1: Coseismic and cumulative three-year-postseismic GNSS observations of the IOE.
Figure 2: Conceptual representation of the finite-element model.
Figure 3: Misfit of 652 test models considering variations in the asthenospheric thickness and viscosity, and oceanic mantle viscosity.
Figure 4: Tradeoff between the viscosity of the oceanic upper mantle (ηO), the thickness (DA) of the asthenosphere and its viscosity (ηA).
Figure 5: Comparison of GNSS observations with predictions of the PM.

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References

  1. Wang, K., Hu, Y. & He, J. Deformation cycles of subduction earthquakes in a viscoelastic Earth. Nature 484, 327–332 (2012)

    Article  CAS  ADS  Google Scholar 

  2. Hu, Y., Wang, K., He, J., Klotz, J. & Khazaradze, G. Three-dimensional viscoelastic finite element model for post-seismic deformation of the great 1960 Chile earthquake. J. Geophys. Res. 109, B12403 (2004)

    Article  ADS  Google Scholar 

  3. Suito, H. & Freymueller, J. T. A viscoelastic and afterslip postseismic deformation model for the 1964 Alaska earthquake. J. Geophys. Res. 114, B11404 (2009)

    Article  ADS  Google Scholar 

  4. Meng, L. et al. Earthquake in a maze: compressional rupture branching during the 2012 M w 8.6 Sumatra earthquake. Science 337, 724–726 (2012)

    Article  CAS  ADS  Google Scholar 

  5. Pollitz, F. F., Stein, R. S., Sevilgen, V. & Bürgmann, R. The 11 April 2012 east Indian Ocean earthquake triggered large aftershocks worldwide. Nature 490, 250–253 (2012)

    Article  CAS  ADS  Google Scholar 

  6. Wei, S., Helmberger, D. & Avouac, J.-P. Modeling the 2012 Wharton basin earthquakes off-Sumatra: complete lithospheric failure. J. Geophys. Res. Solid Earth 118, 3592–3609 (2013)

    Article  ADS  Google Scholar 

  7. Hill, E. M. et al. The 2012 M w 8.6 Wharton Basin sequence: a cascade of great earthquakes generated by near-orthogonal, young, oceanic mantle faults. J. Geophys. Res. Solid Earth 120, 3723–3747 (2015)

    Article  ADS  Google Scholar 

  8. Feng, L. et al. A unified GPS-based earthquake catalog for the Sumatran plate boundary between 2002 and 2013. J. Geophys. Res. Solid Earth 120, 3566–3598 (2015)

    Article  ADS  Google Scholar 

  9. Hu, Y. et al. Contributions of poroelastic rebound and a weak volcanic arc to the postseismic deformation of the 2011 Tohoku earthquake. Earth Planet Space 66, 106 (2014)

    Article  ADS  Google Scholar 

  10. Han, S.-C., Sauber, J. & Pollitz, F. Coseismic compression/dilatation and viscoelastic uplift/subsidence following the 2012 Indian Ocean earthquakes quantified from satellite gravity observations. Geophys. Res. Lett. 42, 3764–3772 (2015)

    Article  ADS  Google Scholar 

  11. Pollitz, F. F., Banerjee, P., Grijalva, K., Nagarajan, B. & Bürgmann, R. B. Effect of 3-D viscoelastic structure on post-seismic relaxation from the 2004 M = 9.2 Sumatra earthquake. Geophys. J. Int. 173, 189–204 (2008)

    Article  ADS  Google Scholar 

  12. Wiseman, K., Bürgmann, R., Freed, A. M. & Banerjee, P. Viscoelastic relaxation in a heterogeneous Earth following the 2004 Sumatra-Andaman earthquake. Earth Planet. Sci. Lett. 431, 308–317 (2015)

    Article  CAS  ADS  Google Scholar 

  13. Hu, Y. et al. Stress-driven relaxation of heterogeneous upper mantle and time-dependent afterslip following the 2011 Tohoku earthquake. J. Geophys. Res. Solid Earth 121, 385–411 (2016)

    Article  CAS  ADS  Google Scholar 

  14. Sun, T. et al. Prevalence of viscoelastic relaxation after the 2011 Tohoku-Oki earthquake. Nature 514, 84–87 (2014)

    Article  CAS  ADS  Google Scholar 

  15. Bürgmann, R. & Dresen, G. Rheology of the lower crust and upper mantle: evidence from rock mechanics, geodesy, and field observations. Annu. Rev. Earth Planet. Sci. 36, 531–567 (2008)

    Article  ADS  Google Scholar 

  16. Yadav, R. K., et al. Coseismic offsets due to the 11 April 2012 Indian Ocean earthquakes (Mw 8.6 and 8.2) derived from GPS measurements. Geophys. Res. Lett. 40, 3389–3393 (2013)

    Article  ADS  Google Scholar 

  17. Shapiro, N. M., Ritzwoller, M. H. & Engdahl, E. R. Structural context of the great Sumatra-Andaman Islands earthquake. Geophys. Res. Lett. 35, L05301 (2008)

    Article  ADS  Google Scholar 

  18. Paulson, A. & Richards, M. A. On the resolution of radial viscosity structure in modelling long-wavelength postglacial rebound data. Geophys. J. Int. 179(3), 1516–1526 (2009)

    Article  ADS  Google Scholar 

  19. Song, T.-R. A. & Kawakatsu, H. Subduction of oceanic asthenosphere: evidence from sub-slab seismic anisotropy. Geophys. Res. Lett. 39, L17301 (2012)

    ADS  Google Scholar 

  20. Huang, J. & Zhao, D. High-resolution mantle tomography of China and surrounding regions. J. Geophys. Res. 111, B09305 (2006)

    ADS  Google Scholar 

  21. Liu, L. & Zhou, Q. Deep recycling of oceanic asthenosphere material during subduction. Geophys. Res. Lett. 42, 2204–2211 (2015)

    Article  ADS  Google Scholar 

  22. Bercovici, D., Tackley, P. & Ricard, Y. in Treatise on Geophysics Vol. 7 Mantle Dynamics (eds Bercovici, D. & Schubert, G. ) 271–318 (Elsevier, 2015)

  23. Weismüller, J. et al. Fast asthenosphere motion in high-resolution global mantle flow models. Geophys. Res. Lett. 42, 7429–7435 (2015)

    Article  ADS  Google Scholar 

  24. Höink, T., A. Jellinek, M. & Lenardic, A. Viscous coupling at the lithosphere–asthenosphere boundary. Geochem. Geophys. Geosyst. 12, Q0AK02 (2011)

    Article  Google Scholar 

  25. Colli, L. I. et al. Rapid South Atlantic spreading changes and coeval vertical motion in surrounding continents: evidence for temporal changes of pressure-driven upper mantle flow. Tectonics 32, 1304–1321 (2014)

    Article  ADS  Google Scholar 

  26. Pollitz, F. F., Bürgmann, R. & Romanowicz, B. Viscosity of oceanic asthenosphere inferred from remote triggering of earthquakes. Science 280, 1245–1249 (1998)

    Article  CAS  ADS  Google Scholar 

  27. Fischer, K. M., Ford, H. A., Abt, D. L. & Rychert, C. A. The lithosphere–asthenosphere boundary. Annu. Rev. Earth Planet. Sci. 38, 551–575 (2010)

    Article  CAS  ADS  Google Scholar 

  28. Karato, S. On the origin of the asthenosphere. Earth Planet. Sci. Lett. 321–322, 95–103 (2012)

    Article  ADS  Google Scholar 

  29. Naif, S., Key, K., Constable, S. & Evans, R. L. Melt-rich channel observed at the lithosphere–asthenosphere boundary. Nature 495, 356–359 (2013)

    Article  CAS  ADS  Google Scholar 

  30. Stern, T. A. et al. A seismic reflection image for the base of a tectonic plate. Nature 518, 85–88 (2015)

    Article  CAS  ADS  Google Scholar 

  31. Schmerr, N. The Gutenberg discontinuity: melt at the lithosphere-asthenosphere boundary. Science 335, 1480–1483 (2012)

    Article  CAS  ADS  Google Scholar 

  32. Yamamoto, J., Korenaga, J., Hirano, N. & Kagi, H. Melt-rich lithosphere–asthenosphere boundary inferred from petit-spot volcanoes. Geology 42, 967–970 (2014)

    Article  ADS  Google Scholar 

  33. Kawakatsu, H. et al. Seismic evidence for sharp lithosphere–asthenosphere boundaries of oceanic plates. Science 324, 499–502 (2009)

    Article  CAS  ADS  Google Scholar 

  34. Altamimi, Z., Collilieux, X. & Métivier, L. ITRF2008: An improved solution of the International Terrestrial Reference Frame. J. Geodyn. 85, 457–473 (2011)

    Article  ADS  Google Scholar 

  35. Hippchen, S. & Hyndman, R. D. Thermal and structural models of the Sumatra subduction zone: implications for the megathrust seismogenic zone. J. Geophys. Res. 113, B12103 (2008)

    Article  ADS  Google Scholar 

  36. Hu, Y. & Wang, K. Spherical-Earth finite element model of short-term postseismic deformation following the 2004 Sumatra earthquake. J. Geophys. Res. 117, B05404 (2012)

    ADS  Google Scholar 

  37. Müller, R. D. et al. Digital isochrons of the world’s ocean floor. J. Geophys. Res. 102, 3211–3214 (1997)

    Article  ADS  Google Scholar 

  38. Jacob, J., Dyment, J. & Yatheesh, V. Revisiting the structure, age, and evolution of the Wharton Basin to better understand subduction under Indonesia. J. Geophys. Res. Solid Earth 119, 169–190 (2014)

    Article  ADS  Google Scholar 

  39. Beghein, B., Yuan, Y., 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  Google Scholar 

  40. Melosh, H. J. & Raefsky, A. A simple and efficient method for introducing faults into finite element computations. Bull. Seismol. Soc. Am. 71, 1391–1400 (1981)

    Google Scholar 

  41. Hawley, W. B., Allen, R. M. & Richards, M. A. Tomography reveals buoyant asthenosphere accumulating beneath the Juan de Fuca plate. Science. 353, 1406–1408 (2016)

    Article  CAS  ADS  Google Scholar 

Download references

Acknowledgements

This work was supported in part by HPC resources from the Arctic Region Supercomputing Center and the University of Alaska Fairbanks. J. He of the Geological Survey of Canada wrote the finite-element computer code used in this work. This work was funded by NSF award EAR-1246850 and benefited from support by the Miller Institute for Basic Research in Science to R.B. and a Singapore National Research Foundation Fellowship to E.M.H. (NRF-NRFF2010-064). J. Paul from the University of Memphis provided GPS data from the Andaman Islands. SuGAr is jointly maintained by the Earth Observatory of Singapore and the Indonesian Institute of Sciences (LIPI). This is Berkeley Seismological Laboratory contribution 2016-5.

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Authors and Affiliations

  1. Berkeley Seismological Laboratory and Department of Earth and Planetary Science, University of California Berkeley, Berkeley, California, USA

    Yan Hu & Roland Bürgmann

  2. Mengcheng National Geophysical Observatory, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, China

    Yan Hu

  3. Earth Observatory of Singapore, Asian School of the Environment, Nanyang Technological University, Singapore

    Paramesh Banerjee, Lujia Feng & Emma M. Hill

  4. Graduate School of Environmental Studies, Nagoya University, Aichi, 464-8601, Japan

    Takeo Ito

  5. Department of Applied Science, Kochi University, Akebono-cho 2-5-1, Kochi, 780-8520, Japan

    Takao Tabei

  6. Pacific Geoscience Centre, Geological Survey of Canada, Natural Resources Canada, Sidney, British Columbia, Canada

    Kelin Wang

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Contributions

Y.H. and R.B. together designed the study and did most of the writing. Y.H. carried out the numerical modelling. P.B., L.F. and E.M.H. collected and processed the daily time series of the SuGAr network. T.I. and T.T. collected and processed the daily time series of the AGNeSS network. K.W. assisted with the modelling strategy. All authors contributed to the interpretations and preparation of the final manuscript.

Corresponding author

Correspondence to Yan Hu.

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The authors declare no competing financial interests.

Additional information

Reviewer Information Nature thanks G. Hirth and W. Thatcher for their contribution to the peer review of this work.

Extended data figures and tables

Extended Data Figure 1 Location of GNSS stations and earthquakes of Mw ≥ 6.5 from 2009 up to the IOE.

Magenta stars represent epicentres of the pre-IOE earthquakes. Red and black arrows represent two-year-postseismic displacements at stations that are used or are excluded in this work, respectively. Station names are labelled with the same colour coding. Solid brown squares, triangles, diamonds and inverted triangles represent GNSS from the SuGAr, IGS, Memphis and AGNeSS networks, respectively.

Extended Data Figure 2 Pre-earthquake daily time series recorded at the GNSS stations shown in Extended Data Fig. 1.

a, b and c show the east, north and up components of the time series, respectively. Coseismic static offsets of one day before and after the earthquakes shown in Extended Data Fig. 1 are removed from the time series. The time series include the total effects of postseismic deformation of previous earthquakes, secular deformation, annual and semi-annual variations. Red and black time series represent those stations that are selected or are excluded in this work, respectively, using the same colour coding as for the station names in Extended Data Fig. 1.

Extended Data Figure 3 Postseismic GNSS time series after removing postseismic deformation of previous earthquakes, secular motion and seasonal variations.

a, b and c show the east, north and up components of the time series, respectively. Red and black lines represent those stations that are selected or are excluded in this work, respectively. Continuous cyan curves fitted to the postseismic time series are used to constrain our postseismic deformation models.

Extended Data Figure 4 Comparison of different source models of the IOE.

a, The coseismic slip distribution is from Wei et al.6, who inverted regional and teleseismic waveform data. Their fault slip model was used in this work. Coseismic GNSS observations are estimated from static offsets of five days before and after the IOE. b, The coseismic slip distribution is from Yadav et al.16, who inverted static offsets of 5 days before and after the IOE of daily GNSS data. Model predictions are scaled by 0.8 to fit the coseismic GNSS data better. c, The coseismic slip distribution is from Hill et al.7, who inverted static offsets of about 10 min before and after the IOE of high-rate (one-second rate) GNSS data in the middle field and of 10 days before and after the IOE of daily GNSS data in the far field. Model predictions are scaled by 1.5 to fit the same GNSS data also shown in a and b better. In the upper panels red and black arrows represent coseismic GNSS observations and model-predicted displacements, respectively. Thick grey lines represent inverted rupture segments of the IOE. In the lower panel of a black arrows and colour contours represent model-predicted three-year-postseismic horizontal and vertical displacements, respectively. In the lower panels of b and c displacements are differenced by the test model minus the model in a.

Extended Data Figure 5 Comparison of three-year-postseismic GNSS observations with predicted displacements in test models of a homogeneous oceanic upper mantle below 50 km without the low-viscosity oceanic asthenosphere.

Red and black arrows represent horizontal GNSS observations and horizontal model-predicted displacements, respectively. Solid brown and blue bars represent vertical GNSS observations and vertical model-predicted displacements, respectively. a, Viscosity of the oceanic upper mantle is 1020 Pa s. b, Viscosity of the oceanic upper mantle is 1019 Pa s.

Extended Data Figure 6 Effects of the extent of the oceanic asthenosphere, layered Earth and variation in the lithospheric thickness on the surface deformation.

Displacements are differenced by a test model minus the PM in which the lithospheric thickness, the thickness (DA) and viscosity (ηA) of the asthenospheric top layer, and the viscosity in the underlying oceanic upper mantle (ηO) are 50 km, 80 km and 2 × 1018 Pa s, and 1020 Pa s, respectively. Black and coloured contours represent the horizontal and vertical displacements, respectively. Thick brown lines outline the location of the trench. a, In the test model the lithospheric thickness is assumed to be 30 km, that is, 20 km thinner than in the PM. b, Similar to a except that the lithospheric thickness is 70 km. c, In the test model the slab does not exist. d, In the test model the oceanic asthenosphere terminates at the trench and does not extend with the downgoing subducting slab. Thick grey lines in a represent rupture segments of the IOE.

Extended Data Figure 7 Contributions of viscoelastic relaxation in the rheological units and afterslip of the IOE to the cumulative three-year-postseismic surface deformation.

a, Surface deformation due to viscoelastic relaxation in the oceanic asthenosphere alone. The continental and oceanic upper mantle are assumed to be elastic. b, Surface deformation due to viscoelastic relaxation in the oceanic upper mantle alone. c, Surface deformation due to viscoelastic relaxation in the mantle wedge alone. Thick grey lines represent the rupture segments of the IOE. d, Surface deformation due to the modelled afterslip in the shear zone assuming no viscoelastic relaxation elsewhere. Open arrows and colour contours represent horizontal and vertical model-predicted displacements, respectively.

Extended Data Figure 8 Effects of afterslip after the IOE on the surface deformation.

a, Steady-state viscosity in the afterslip shear zone ηS is 5 × 1017 Pa s, and ηA = 2 × 1018 Pa s. Afterslip is allowed at depths 0–65 km. Red and black arrows represent horizontal GNSS observations and model-predicted displacements, respectively. Solid magenta and white bars represent vertical GNSS observations and model-predicted displacements, respectively. Yellow arrows and colour contours represent differential horizontal (DIFF − Hori) and vertical (DIFF − Vert) components by the test model minus the PM, respectively. b, Similar to a except with a low ηS = 1017 Pa s. c, Similar to a except with a high ηS = 1018 Pa s. d, Similar to a except that the afterslip is allowed only at shallow depths (≤50 km) and no deep afterslip. e, Similar to a except that the afterslip is allowed only at greater depths (50–65 km), and no shallow afterslip. f, ηS = 5 × 1017 Pa s, and ηA = 1020 Pa s. Afterslip is allowed at depths of 0–65 km.

Extended Data Figure 9 Three-year-postseismic displacements due to changes in model parameters and comparison of GNSS observations with predicted displacements.

a, Surface deformation calculated by the test model minus the PM. In the test model the asthenosphere terminates at the trench and does not extend with the downgoing slab. ηA is one order of magnitude lower than that of the PM. Other model parameters are the same as the PM. Black arrows and contours represent horizontal and vertical three-year-postseismic surface displacements, respectively. Thick grey lines represent rupture segments of the IOE. b, Similar to a except that ηA is the same as in the PM but DA = 200 km, more than two times thicker than that of the PM. c, The sharp boundary between the lithosphere and the asthenosphere in the PM is replaced by a 20-km-thick transition zone in which the viscosity decreases linearly with depth from 1022 Pa s at the bottom of the lithosphere to the preferred 2 × 1018 Pa s of the asthenosphere. d and e are the test models best fitting to the horizontal (Fig. 3a) and vertical (Fig. 3b) GNSS observations, respectively. Red and black arrows represent horizontal GNSS observations and horizontal model-predicted displacements, respectively. Solid brown and blue bars represent vertical GNSS observations and vertical model-predicted displacements, respectively. Thick grey lines represent the rupture segments of the IOE. f, Preferred lowest misfit test model (PM) best fitting to both horizontal and vertical GNSS data (Fig. 3c), the same data as in Fig. 5a. Values of the viscosity of the oceanic upper mantle (ηO), thickness (DA) and viscosity (ηA) of the asthenosphere in each test model are labelled on the top of each plot in d and e. The value of χ2 in each test model is labelled as inset text.

Extended Data Figure 10 Postseismic displacement evolution in the PM.

a, b and c show cumulative surface postseismic displacements at one year, three years, and ten years after the earthquake, respectively. Black arrows and contours represent horizontal and vertical displacements, respectively. Thick grey lines in a represent the rupture segments of the IOE. d, e and f show the evolution of postseismic displacements in the east, north and up directions, respectively, at four surface example points of the same latitude 3° N whose locations are at trench (red lines), western (black) and eastern (green) coast of Sumatra, and inland (blue). Locations of these four points are also shown as solid dots in a with the same colour coding.

Supplementary information

Supplementary Table 1

This table shows three-year cumulative postseismic GPS displacements. (CSV 3 kb)

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Hu, Y., Bürgmann, R., Banerjee, P. et al. Asthenosphere rheology inferred from observations of the 2012 Indian Ocean earthquake. Nature 538, 368–372 (2016). https://doi.org/10.1038/nature19787

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