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Larger tsunamis from megathrust earthquakes where slab dip is reduced

Abstract

A subset of megathrust earthquakes produce anomalously large tsunamis for their magnitude. All of these recorded ‘tsunami earthquakes’ in the past 50 years had extensional aftershocks in the upper plate. These include the two largest and most destructive earthquakes of that period, the 2004 Sumatra–Andaman and the 2011 Tohoku events. Evidence from the region of Tohoku indicates that normal fault slip in the upper plate during the earthquake may have contributed to the tsunami size. Here we present a numerical model that shows how a reduction of the dip of a subducting slab, on a timescale of millions of years, can result in an extensional fault failure above a megathrust earthquake on timescales of seconds to months. Slab dip reduction bends the upper plate so that the shallow part fails in extension when a megathrust rupture relieves compressional stress. This results in a distribution of extensional aftershocks comparable to that seen above the Tohoku megathrust. Volcanic arc migration and uplift data for Tohoku and several other tsunami earthquakes is consistent with slab dip reduction. The collection of more such data might identify other areas of tsunami hazard related to slab dip reduction.

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Fig. 1: Foreshocks and aftershocks for the Tohoku and Sumatra–Andaman megathrust earthquakes.
Fig. 2: Plot of tsunami magnitude (Mt) versus surface wave moment (Ms) for earthquakes that generated tsunamis.
Fig. 3: Cartoon showing the effect of decreasing the subducting slab dip angle on upper plate bending, and the location of the volcanic arc.
Fig. 4: Snapshots showing how slab dip changes can alter the upper plate stress state.
Fig. 5: Illustration of stress changes through an earthquake cycle for the slab dip reduction case.
Fig. 6: Evidence of slab dip reduction over time at the Japan and Java Trenches where tsunami earthquakes have occurred.

Data availability

Source data for Fig. 2 are provided as a Source Data file. The location and timing of aftershocks for the Tohoku, Sumatra–Andaman and Java events can be found in the Iris catalogue (http://service.iris.edu/fdsnws/event/1/) or by contacting the corresponding authors of the aftershocks papers cited within this article.

Code availability

The numerical code we used for these model runs can be found at https://bitbucket.org/tan2/flac/src/default/.

References

  1. 1.

    Lay, T. A review of the rupture characteristics of the 2011 Tohoku-oki Mw 9.1 earthquake. Tectonophysics 733, 4–36 (2018).

    Google Scholar 

  2. 2.

    Fujiwara, T. et al. The 2011 Tohoku-Oki earthquake: displacement reaching the trench axis. Science 334, 1240 (2011).

    Google Scholar 

  3. 3.

    Sun, T., Wang, K., Fujiwara, T., Kodaira, S. & He, J. Large fault slip peaking at trench in the 2011 Tohoku-oki earthquake. Nat. Commun, 8, 14044 (2017).

    Google Scholar 

  4. 4.

    Maeda, T., Furumura, T., Sakai, S. & Shinohara, M. Significant tsunami observed at ocean-bottom pressure gauges during the 2011 off the Pacific coast of Tohoku Earthquake. Earth Planets Space 63, 803–808 (2011).

    Google Scholar 

  5. 5.

    Sato, M. et al. Displacement above the hypocenter of the 2011 Tohoku-Oki earthquake. Science 332, 1395 (2011).

    Google Scholar 

  6. 6.

    Iinuma, T. et al. Coseismic slip distribution of the 2011 off the Pacific Coast of Tohoku earthquake (M9.0) refined by means of seafloor geodetic data. J. Geophys. Res. Solid Earth 117, B07409 (2012).

    Google Scholar 

  7. 7.

    Simons, M. et al. The 2011 magnitude 9.0 Tohoku-Oki earthquake: mosaicking the megathrust from seconds to centuries. Science 332, 1421–1425 (2011).

    Google Scholar 

  8. 8.

    Fujii, Y., Satake, K., Sakai, S., Shinohara, M. & Kanazawa, T. Tsunami source of the 2011 off the Pacific coast of Tohoku earthquake. Earth Planets Space 63, 815–820 (2011).

    Google Scholar 

  9. 9.

    Yagi, Y. & Fukahata, Y. Rupture process of the 2011 Tohoku-oki earthquake and absolute elastic strain release. Geophys. Res. Lett. 38, L19307 (2011).

    Google Scholar 

  10. 10.

    Shao, G., Li, X., Ji, C. & Maeda, T. Focal mechanism and slip history of the 2011 Mw 9.1 off the Pacific coast of Tohoku earthquake, constrained with teleseismic body and surface waves. Earth Planets Space 63, 559–564 (2011).

    Google Scholar 

  11. 11.

    Hyndman, R. D., Yamano, M. & Oleskevich, D. A. The seismogenic zone of subduction thrust faults. Isl. Arc 6, 244–260 (1997).

    Google Scholar 

  12. 12.

    Byrne, D. E., Davis, D. M. & Sykes, L. R. Loci and maximum size of thrust earthquakes and the mechanics of the shallow region of subduction zones. Tectonics 7, 833–857 (1988).

    Google Scholar 

  13. 13.

    Moore, J. C. & Saffer, D. Updip limit of the seismogenic zone beneath the accretionary prism of Southwest Japan: an effect of diagenetic to low-grade metamorphic processes and increasing effective stress. Geology 29, 183–186 (2001).

    Google Scholar 

  14. 14.

    Lay, T. et al. Depth-varying rupture properties of subduction zone megathrust faults. J. Geophys. Res. Solid Earth 117, B04311 (2012).

    Google Scholar 

  15. 15.

    Kajitani, Y., Chang, S. E. & Tatano, H. Economic impacts of the 2011 Tohoku-oki earthquake and tsunami. Earthq. Spectra 39, 457–478 (2013).

    Google Scholar 

  16. 16.

    Tsuji, T. et al. Extension of continental crust by anelastic deformation during the 2011 Tohoku-oki earthquake: the role of extensional faulting in the generation of a great tsunami. Earth Planet. Sci. Lett. 364, 44–58 (2013).

    Google Scholar 

  17. 17.

    Tsuji, T. et al. Potential tsunamigenic faults of the 2011 off the Pacific coast of Tohoku Earthquake. Earth Planets Space 63, 58 (2011).

    Google Scholar 

  18. 18.

    Hasegawa, A. et al. Change in stress field after the 2011 great Tohoku-Oki earthquake. Earth Planet. Sci. Lett. 355–356, 231–243 (2012).

    Google Scholar 

  19. 19.

    Imanishi, K., Ando, R. & Kuwahara, Y. Unusual shallow normal-faulting earthquake sequence in compressional northeast Japan activated after the 2011 off the Pacific coast of Tohoku earthquake. Geophys. Res. Lett. 39, L09306 (2012).

    Google Scholar 

  20. 20.

    Lin, W. et al. Principal horizontal stress orientations prior to the 2011 Mw 9.0 Tohoku-Oki, Japan, earthquake in its source area. Geophys. Res. Lett. 38, L00G10 (2011).

    Google Scholar 

  21. 21.

    Hardebeck, J. L. Coseismic and postseismic stress rotations due to great subduction zone earthquakes. Geophys. Res. Lett. 39, L21313 (2012).

    Google Scholar 

  22. 22.

    Hasegawa, A., Yoshida, K. & Okada, T. Nearly complete stress drop in the 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake. Earth Planets Space 63, 703–707 (2011).

    Google Scholar 

  23. 23.

    Ishii, M., Shearer, P. M., Houston, H. & Vidale, J. E. Extent, duration and speed of the 2004 Sumatra–Andaman earthquake imaged by the Hi-Net array. Nature 435, 933–936 (2005).

    Google Scholar 

  24. 24.

    Ammon, C. J. et al. Rupture process of the 2004 Sumatra–Andaman earthquake. Science 308, 1133–1139 (2005).

    Google Scholar 

  25. 25.

    McKenzie, D. & Jackson, J. Tsunami earthquake generation by the release of gravitational potential energy. Earth Planet. Sci. Lett. 345–348, 1–8 (2012).

    Google Scholar 

  26. 26.

    Kanamori, H. Mechanism of tsunami earthquakes. Phys. Earth Planet. Inter. 6, 346–359 (1972).

    Google Scholar 

  27. 27.

    Polet, J. & Kanamori, H. Shallow subduction zone earthquakes and their tsunamigenic potential. Geophys. J. Int. 142, 684–702 (2000).

    Google Scholar 

  28. 28.

    Ide, S., Baltay, A. & Beroza, G. C. Shallow dynamic overshoot and energetic deep rupture in the 2011 Mw 9.0 Tohoku-Oki earthquake. Science 332, 1426–1429 (2011).

    Google Scholar 

  29. 29.

    Brace, W. F. & Kohlstedt, D. L. Limits on lithospheric stress imposed by laboratory experiments. J. Geophys. Res. Solid Earth 85, 6248–6252 (1980).

    Google Scholar 

  30. 30.

    Conin, M., Henry, P., Godard, V. & Bourlange, S. Splay fault slip in a subduction margin, a new model of evolution. Earth Planet. Sci. Lett. 341–344, 170–175 (2012); erratum 357358, 423 (2012).

    Google Scholar 

  31. 31.

    Cubas, N., Avouac, J. P., Souloumiac, P. & Leroy, Y. Megathrust friction determined from mechanical analysis of the forearc in the Maule earthquake area. Earth Planet. Sci. Lett. 381, 92–103 (2013).

    Google Scholar 

  32. 32.

    Christensen, D. H. & Ruff, L. J. Outer‐rise earthquakes and seismic coupling. Geophys. Res. Lett. 10, 697–700 (1983).

    Google Scholar 

  33. 33.

    Buck, W. R., Lavier, L. L. & Petersen, K. D. in AGU Fall Meeting Abstracts T12C-01 (AGU, 2015).

  34. 34.

    Oryan, B. & Buck, W. R. in AGU Fall Meeting Abstracts T23F-0661 (AGU, 2017).

  35. 35.

    Sibson, R. H. Interactions between temperature and pore-fluid pressure during earthquake faulting and a mechanism for partial or total stress relief. Nat. Phys. Sci. 243, 66–68 (1973).

    Google Scholar 

  36. 36.

    Cundall, P. A. Numerical experiments on localization in frictional materials. Ing. Arch. 59, 148–159 (1989).

    Google Scholar 

  37. 37.

    Gurnis, M., Hall, C. & Lavier, L. Evolving force balance during incipient subduction. Geochem. Geophys. Geosyst. 5, Q07001 (2004).

    Google Scholar 

  38. 38.

    Biemiller, J. & Lavier, L. Earthquake supercycles as part of a spectrum of normal fault slip styles. J. Geophys. Res. Solid Earth 122, 3221–3240 (2017).

    Google Scholar 

  39. 39.

    Sobolev, S. V. & Muldashev, I. A. Modeling seismic cycles of great megathrust earthquakes across the scales with focus at postseismic phase. Geochem. Geophys. Geosyst. 18, 4387–4408 (2017).

    Google Scholar 

  40. 40.

    Lallemand, S., Heuret, A., Faccenna, C. & Funiciello, F. Subduction dynamics as revealed by trench migration. Tectonics 27, TC3014 (2008).

    Google Scholar 

  41. 41.

    King, G. C. P., Stein, R. S. & Lin, J. Static stress changes and the triggering of earthquakes. Bull. Seismol. Soc. Am. 84, 935–953 (1994).

    Google Scholar 

  42. 42.

    Tatsumi, Y., Hamilton, D. L. & Nesbitt, R. W. Chemical characteristics of fluid phase released from a subducted lithosphere and origin of arc magmas: evidence from high-pressure experiments and natural rocks. J. Volcanol. Geotherm. Res. 29, 293–309 (1986).

    Google Scholar 

  43. 43.

    Tatsumi, Y., Otofuji, Y.-I., Matsuda, T. & Nohda, S. Opening of the Sea of Japan back-arc basin by asthenospheric injection. Tectonophysics 166, 317–329 (1989).

    Google Scholar 

  44. 44.

    Regalla, C., Fisher, D. M., Kirby, E. & Furlong, K. P. Relationship between outer forearc subsidence and plate boundary kinematics along the Northeast Japan convergent margin. Geochem. Geophys. Geosyst. 14, 5227–5243 (2013).

    Google Scholar 

  45. 45.

    Wang, K. et al. Stable forearc stressed by a weak megathrust: mechanical and geodynamic implications of stress changes caused by the M = 9 Tohoku-Oki earthquake. J. Geophys. Res. Solid Earth 124, 6179–6194 (2019).

    Google Scholar 

  46. 46.

    Zoback, M. D., Townend, J. & Grollimund, B. Steady-state failure equilibrium and deformation of intraplate lithosphere. Int. Geol. Rev. 44, 383–401 (2002).

    Google Scholar 

  47. 47.

    Plank, T., Balzer, V. & Carr, M. Nicaraguan volcanoes record paleoceanographic changes accompanying closure of the Panama gateway. Geology 30, 1087–1090 (2002).

    Google Scholar 

  48. 48.

    Abe, K. Quantification of tsunamigenic earthquakes by the Mt scale. Tectonophysics 166, 27–34 (1989).

    Google Scholar 

  49. 49.

    Lay, T., Ammon, C. J., Kanamori, H., Xue, L. & Kim, M. J. Possible large near-trench slip during the 2011 Mw 9.0 off the Pacific coast of Tohoku earthquake. Earth Planets Space 63, 687–692 (2011).

    Google Scholar 

  50. 50.

    Smyth, H., Hall, R., Hamilton, J. & Kinny, P. East Java: Cenozoic basins, volcanoes and ancient basement. In Proc. Indonesia Petroleum Association, 30th Annual Convention 251–266 (Indonesian Petroleum Association, 2005).

  51. 51.

    Kanamori, H. & Kikuchi, M. The 1992 Nicaragua earthquake: a slow tsunami earthquake associated with subducted sediments. Nature 361, 714–716 (1993).

    Google Scholar 

  52. 52.

    Satake, K. & Tanioka, Y. Sources of tsunami and tsunamigenic earthquakes in subduction zones. Pure Appl. Geophys. 154, 467–483 (1999).

    Google Scholar 

  53. 53.

    Lavier, L. L., Buck, W. R. & Poliakov, A. N. B. Factors controlling normal fault offset in an ideal brittle layer. J. Geophys. Res. Solid Earth 105, 23431–23442 (2000).

    Google Scholar 

  54. 54.

    Poliakov, A. N. B., Podladchikov, Y. & Talbot, C. Initiation of salt diapirs with frictional overburdens: numerical experiments. Tectonophysics 228, 199–210 (1993).

    Google Scholar 

  55. 55.

    Lavier, L. L. & Buck, W. R. Half graben versus large-offset low-angle normal fault: importance of keeping cool during normal faulting. J. Geophys. Res. 107, 2122 (2002).

    Google Scholar 

  56. 56.

    Qin, R. & Buck, W. R. Why meter-wide dikes at oceanic spreading centers? Earth Planet. Sci. Lett. 265, 466–474 (2008).

    Google Scholar 

  57. 57.

    Hall, C. E., Gurnis, M., Sdrolias, M., Lavier, L. L. & Müller, R. D. Catastrophic initiation of subduction following forced convergence across fracture zones. Earth Planet. Sci. Lett. 212, 15–30 (2003).

    Google Scholar 

  58. 58.

    Karato & Wu Rheology of the upper mantle: a synthesis. Science 260, 771–778 (1993).

    Google Scholar 

  59. 59.

    Jaeger, J. C., Cook, N. G. W. & Zimmerman, R. Fundamentals of Rock Mechanics 4th edn (Wiley, 2007).

  60. 60.

    Poliakov, A. N. B. & Buck, W. R. Mechanics of stretching elastic-plastic-viscous layers: applications to slow-spreading mid-ocean ridges. Geophys. Monogr. Ser. 106, 305–323 (1998).

    Google Scholar 

  61. 61.

    Choi, E., Buck, W. R., Lavier, L. L. & Petersen, K. D. Using core complex geometry to constrain fault strength. Geophys. Res. Lett. 40, 3863–3867 (2013).

    Google Scholar 

  62. 62.

    Martinod, J. et al. How do subduction processes contribute to forearc Andean uplift? Insights from numerical models. J. Geodyn. 96, 6–18 (2016).

    Google Scholar 

  63. 63.

    Hassani, R., Jongmans, D. & Chéry, J. Study of plate deformation and stress in subduction processes using two-dimensional numerical models. J. Geophys. Res. Solid Earth 102, 17951–17952 (1997).

    Google Scholar 

  64. 64.

    Guillaume, B., Hertgen, S., Martinod, J. & Cerpa, N. G. Slab dip, surface tectonics: how and when do they change following an acceleration/slow down of the overriding plate? Tectonophysics 726, 110–120 (2018).

    Google Scholar 

  65. 65.

    Scholz, C. H. & Campos, J. On the mechanism of seismic decoupling and back arc spreading at subduction zones. J. Geophys. Res. Solid Earth 100, 22103–22115 (1995).

    Google Scholar 

  66. 66.

    Syracuse, E. M. & Abers, G. A. Global compilation of variations in slab depth beneath arc volcanoes and implications. Geochem. Geophys. Geosyst. 7, Q05017 (2006).

    Google Scholar 

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Acknowledgements

We thank M. Steckler and H. Savage for their support and comments and for suggestions made by G. Coffey. We are appreciative of K. Key and his group for letting us use their computational resources. This project was supported by NSF EAR 17-14892. Lamont-Doherty Earth Observatory publication no. 8382.

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B.O. wrote sections of the code applicable for this project, ran the models and analysed the results. W.R.B. planned and oversaw the study. B.O. wrote and W.R.B. edited the manuscript.

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Correspondence to Bar Oryan.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–10, Tables 1-4 and discussion.

Supplementary Video 1

Aftershocks animation.

Source data

Source Data Fig. 2

Source data for Fig. 2.

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Oryan, B., Buck, W.R. Larger tsunamis from megathrust earthquakes where slab dip is reduced. Nat. Geosci. 13, 319–324 (2020). https://doi.org/10.1038/s41561-020-0553-x

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