Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Subslab heterogeneity and giant megathrust earthquakes


The nucleation and rupture processes of giant megathrust earthquakes (M ≥ 9.0) in subduction zones are still controversial. Most previous studies have focused on the subducting plate interface, and the structure beneath the subducting slab and its influence on earthquake generation remain unclear. Here, we present high-resolution seismic velocity tomography beneath six regions where giant earthquakes have occurred. Subslab low-velocity (slow) anomalies are revealed, which may reflect hot mantle upwelling. The giant earthquake hypocentres are generally located above the edges of the slow anomalies or above the gaps between them. Large coseismic slips of the giant earthquakes mainly occurred above gaps between the slow anomalies. We suggest that differential buoyancy force between the slow anomalies and their gaps may be an important factor for earthquake nucleation, and the rupture extent of a giant earthquake may be constrained by the slow anomalies. Hence, it is necessary to conduct seismic tomography to investigate the detailed subslab structure, which may help to pinpoint the potential location and damage zone of a future giant earthquake.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Subslab Vp images and coseismic slips (purple contours) of six giant earthquakes.
Fig. 2: Subslab low-velocity anomalies and coseismic slips of giant earthquakes.
Fig. 3: Schematic illustrating the influence of subslab heterogeneity on the generation of giant earthquakes.

Data availability

All data needed to evaluate the conclusions in the paper are provided in the paper and/or the Supplementary Information. All the 3D velocity models may be requested from the authors. The waveform data and P-wave arrival-time data were downloaded free from the Data Management Center of Hi-net and S-net ( and the ISC website (

Code availability

The free software GMT ( and AIMBAT56 were used in this study. The analysis codes and related scripts for generating figures used in the main text and Supplementary Information are available from the corresponding authors upon reasonable request.


  1. 1.

    Satake, K., Shimazaki, K., Tsuji, Y. & Ueda, K. Time and size of a giant earthquake in Cascadia inferred from Japanese tsunami records of January 1700. Nature 379, 246–249 (1996).

    Article  Google Scholar 

  2. 2.

    Wang, P. L. et al. Heterogeneous rupture in the great Cascadia earthquake of 1700 inferred from coastal subsidence estimates. J. Geophys. Res. Solid Earth 118, 2460–2473 (2013).

    Article  Google Scholar 

  3. 3.

    Johnson, J. M. & Satake, K. Asperity distribution of the 1952 great Kamchatka earthquake and its relation to future earthquake potential in Kamchatka. Pure Appl. Geophys. 154, 541–553 (1999).

    Article  Google Scholar 

  4. 4.

    Moreno, M., Bolte, J., Klotz, J. & Melnick, D. Impact of megathrust geometry on inversion of coseismic slip from geodetic data: application to the 1960 Chile earthquake. Geophys. Res. Lett. 36, L16310 (2009).

    Article  Google Scholar 

  5. 5.

    Ichinose, G., Somerville, P., Thio, H. K., Graves, R. & O’Connell, D. Rupture process of the 1964 Prince William Sound, Alaska, earthquake from the combined inversion of seismic, tsunami and geodetic data. J. Geophys. Res. 112, B07306 (2007).

    Google Scholar 

  6. 6.

    Chlieh, M. et al. Coseismic slip and afterslip of the great Mw 9.15 Sumatra–Andaman earthquake of 2004. Bull. Seismol. Soc. Am. 97, S152–S173 (2007).

    Article  Google Scholar 

  7. 7.

    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. 117, B07409 (2012).

    Article  Google Scholar 

  8. 8.

    Scholz, C. H. & Campos, J. The seismic coupling of subduction zones revisited. J. Geophys. Res. 117, B05310 (2012).

    Article  Google Scholar 

  9. 9.

    Heuret, A., Conrad, C. P., Funiciello, F., Lallemand, S. & Sandri, L. Relation between subduction megathrust earthquakes, trench sediment thickness and upper plate strain. Geophys. Res. Lett. 39, L05304 (2012).

    Article  Google Scholar 

  10. 10.

    Song, T. R. A. & Simons, M. Trench-parallel gravity variations predict seismogenic behavior in subduction zones. Science 301, 630–633 (2003).

    Article  Google Scholar 

  11. 11.

    Schellart, W. P. & Rawlinson, N. Global correlations between maximum magnitudes of subduction zone interface thrust earthquakes and physical parameters of subduction zones. Phys. Earth Planet. Inter. 225, 41–67 (2013).

    Article  Google Scholar 

  12. 12.

    Nishikawa, T. & Ide, S. Earthquake size distribution in subduction zones linked to slab buoyancy. Nat. Geosci. 7, 904–908 (2014).

    Article  Google Scholar 

  13. 13.

    Gao, X. & Wang, K. Strength of stick-slip and creeping subduction megathrusts from heat flow observations. Science 345, 1038–1041 (2014).

    Article  Google Scholar 

  14. 14.

    Bletery, Q. et al. Mega-earthquakes rupture flat megathrusts. Science 354, 1027–1031 (2016).

    Article  Google Scholar 

  15. 15.

    Liu, X. & Zhao, D. Upper and lower plate controls on the great 2011 Tohoku-oki earthquake. Sci. Adv. 4, eaat4396 (2018).

    Article  Google Scholar 

  16. 16.

    Bodmer, M., Toomey, D. R., Hooft, E. E. E. & Schmandt, B. Buoyant asthenosphere beneath Cascadia influences megathrust segmentation. Geophys. Res. Lett. 45, 6954–6962 (2018).

    Article  Google Scholar 

  17. 17.

    Bodmer, M., Toomey, D. R., Roering, J. J. & Karlstrom, L. Asthenospheric buoyancy and the origin of high-relief topography along the Cascadia forearc. Earth Planet. Sci. Lett. 531, 115965 (2020).

    Article  Google Scholar 

  18. 18.

    Chen, C., Zhao, D. & Wu, S. Tomographic imaging of the Cascadia subduction zone: constraints on the Juan de Fuca slab. Tectonophysics 647-648, 73–88 (2015).

    Article  Google Scholar 

  19. 19.

    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  Google Scholar 

  20. 20.

    Liu, X. & Zhao, D. P and S wave tomography of Japan subduction zone from joint inversions of local and teleseismic travel times and surface-wave data. Phys. Earth Planet. Inter. 252, 1–22 (2016).

    Article  Google Scholar 

  21. 21.

    Portner, D. E., Beck, S., Zandt, G. & Scire, A. The nature of subslab slow velocity anomalies beneath South America. Geophys. Res. Lett. 44, 4747–4755 (2017).

    Article  Google Scholar 

  22. 22.

    Pesicek, J., Engdahl, E., Thurber, C., DeShon, H. & Lange, D. Mantle subducting slab structure in the region of the 2010 M8.8 Maule earthquake (30–40° S), Chile. Geophys. J. Int. 191, 317–324 (2012).

    Article  Google Scholar 

  23. 23.

    Huang, Z., Zhao, D. & Wang, L. P wave tomography and anisotropy beneath Southeast Asia: insight into mantle dynamics. J. Geophys. Res. Solid Earth 120, 5154–5174 (2015).

    Article  Google Scholar 

  24. 24.

    Wirth, E. A. & Frankel, A. D. Impact of down-dip rupture limit and high-stress drop subevents on coseismic land-level change during Cascadia megathrust earthquakes. Bull. Seismol. Soc. Am. 109, 2187–2197 (2019).

    Article  Google Scholar 

  25. 25.

    Griffin, J., Nguyen, N., Cummins, P. & Cipta, A. Historical earthquakes of the eastern Sunda Arc: source mechanisms and intensity-based testing of Indonesia’s national seismic hazard assessment. Bull. Seismol. Soc. Am. 109, 43–65 (2019).

    Article  Google Scholar 

  26. 26.

    Zhao, D., Yanada, T., Hasegawa, A., Umino, N. & Wei, W. Imaging the subducting slabs and mantle upwelling under the Japan Islands. Geophys. J. Int. 190, 816–828 (2012).

    Article  Google Scholar 

  27. 27.

    Gorbatov, A., Fukao, Y., Widiyantoro, S. & Gordeev, E. Seismic evidence for a mantle plume oceanwards of the Kamchatka–Aleutian trench junction. Geophys. J. Int. 146, 282–288 (2001).

    Article  Google Scholar 

  28. 28.

    Honda, S., Morishige, M. & Orihashi, Y. Sinking hot anomaly trapped at the 410-km discontinuity near the Honshu subduction zone, Japan. Earth Planet. Sci. Lett. 261, 565–577 (2007).

    Article  Google Scholar 

  29. 29.

    Morgan, J. P., Hasenclever, J. & Shi, C. New observational and experimental evidence for a plume-fed asthenosphere boundary layer in mantle convection. Earth Planet. Sci. Lett. 366, 99–111 (2013).

    Article  Google Scholar 

  30. 30.

    Zhao, D. Seismic images under 60 hotspots: search for mantle plumes. Gondwana Res. 12, 335–355 (2007).

    Article  Google Scholar 

  31. 31.

    Hicks, S. P., Nippress, S. E. J. & Rietbrock, A. Sub-slab mantle anisotropy beneath south-central Chile. Earth Planet. Sci. Lett. 357–358, 203–213 (2012).

    Article  Google Scholar 

  32. 32.

    Long, M. D. & Silver, P. G. The subduction zone flow field from seismic anisotropy: a global view. Science 319, 315–318 (2008).

    Article  Google Scholar 

  33. 33.

    Bezada, M. J., Faccenda, M. & Toomey, D. R. Representing anisotropic subduction zones with isotropic velocity models: a characterization of the problem and some steps on a possible path forward. Geochem. Geophys. Geosyst. 17, 3164–3189 (2016).

    Article  Google Scholar 

  34. 34.

    Liu, X. & Zhao, D. Seismic velocity azimuthal anisotropy of the Japan subduction zone: constraints from P and S wave traveltimes. J. Geophys. Res. Solid Earth 121, 5086–5115 (2016).

    Article  Google Scholar 

  35. 35.

    Gou, T., Zhao, D., Huang, Z. & Wang, L. Aseismic deep slab and mantle flow beneath Alaska: insight from anisotropic tomography. J. Geophys. Res. Solid Earth 124, 1700–1724 (2019).

    Article  Google Scholar 

  36. 36.

    Hall, R. & Spakman, W. Mantle structure and tectonic history of SE Asia. Tectonophysics 658, 14–45 (2015).

    Article  Google Scholar 

  37. 37.

    Rosenbaum, G. & Mo, W. Tectonic and magmatic responses to the subduction of high bathymetric relief. Gondwana Res. 19, 571–582 (2011).

    Article  Google Scholar 

  38. 38.

    Lee, S. J., Huang, B. S., Ando, M., Chiu, H. C. & Wang, J. H. Evidence of large scale repeating slip during the 2011 Tohoku-oki earthquake. Geophys. Res. Lett. 38, L19306 (2011).

    Google Scholar 

  39. 39.

    Zhang, N., Dang, Z., Huang, C. & Li, Z. X. The dominant driving force for supercontinent breakup: plume push or subduction retreat? Geosci. Front. 9, 997–1007 (2018).

    Article  Google Scholar 

  40. 40.

    Scholz, C. H. On the stress dependence of the earthquake b value. Geophys. Res. Lett. 42, 1399–1402 (2015).

    Article  Google Scholar 

  41. 41.

    Müller, R. D., Sdrolias, M., Gaina, C. & Roest, W. R. Age, spreading rates and spreading asymmetry of the world’s ocean crust. Geochem. Geophys. Geosyst. 9, Q04006 (2008).

    Article  Google Scholar 

  42. 42.

    Bürgmann, R. et al. Interseismic coupling and asperity distribution along the Kamchatka subduction zone. J. Geophys. Res. 110, B07405 (2005).

    Article  Google Scholar 

  43. 43.

    Chlieh, M., Avouac, J. P., Sieh, K., Natawidjaja, D. H. & Galetzka, J. Heterogeneous coupling of the Sumatran megathrust constrained by geodetic and paleogeodetic measurements. J. Geophys. Res. 113, B05305 (2008).

    Article  Google Scholar 

  44. 44.

    Gou, T., Zhao, D., Huang, Z. & Wang, L. Structural heterogeneity in source zones of the 2018 Anchorage intraslab earthquake and the 1964 Alaska megathrust earthquake. Geochem. Geophys. Geosyst. 21, e2019GC008812 (2020).

    Article  Google Scholar 

  45. 45.

    Nishikawa, T. et al. The slow earthquake spectrum in the Japan Trench illuminated by the S-net seafloor observatories. Science 365, 808–813 (2019).

    Article  Google Scholar 

  46. 46.

    Chuang, L., Bostock, M., Wech, A. & Plourde, A. Plateau subduction, intraslab seismicity and the Denali (Alaska) volcanic gap. Geology 45, 647–650 (2017).

    Article  Google Scholar 

  47. 47.

    Kato, N. Interaction of slip on asperities: numerical simulation of seismic cycles on a two-dimensional planar fault with nonuniform frictional property. J. Geophys. Res. 109, B12306 (2004).

    Article  Google Scholar 

  48. 48.

    Zhao, D. Multiscale Seismic Tomography (Springer, 2015).

  49. 49.

    Engdahl, E. R., van der Hilst, R. & Buland, R. Global teleseismic earthquake relocation with improved travel times and procedures for depth determination. Bull. Seismol. Soc. Am. 88, 722–743 (1998).

    Google Scholar 

  50. 50.

    Weston, J., Engdahl, E. R., Harris, J., Di Giacomo, D. & Storchack, D. A. ISC-EHB: reconstruction of a robust earthquake dataset. Geophys. J. Int. 214, 474–484 (2018).

    Article  Google Scholar 

  51. 51.

    Okada, Y. et al. Recent progress of seismic observation networks in Japan –Hi-net, F-net, K-NET and KiK-net–. Earth Planets Space 56, xv–xxviii (2004).

    Article  Google Scholar 

  52. 52.

    Uehira, K. et al. S-net project: construction of large-scale seismic and tsunami observation system on seafloor along the Japan Trench. Geophys. Res. Abstr. 20, EGU2018–12000 (2018).

    Google Scholar 

  53. 53.

    Zhao, D., Yamamoto, Y. & Yanada, T. Global mantle heterogeneity and its influence on teleseismic regional tomography. Gondwana Res. 23, 595–616 (2013).

    Article  Google Scholar 

  54. 54.

    Zhao, D., Hasegawa, A. & Kanamori, H. Deep structure of Japan subduction zone as derived from local, regional and teleseismic events. J. Geophys. Res. 99, 22313–22329 (1994).

    Article  Google Scholar 

  55. 55.

    Fan, J. & Zhao, D. P-wave anisotropic tomography of the central and southern Philippines. Phys. Earth Planet. Inter. 286, 154–164 (2019).

    Article  Google Scholar 

  56. 56.

    Lou, X., van der Lee, S. & Lloyd, S. AIMBAT: a Python/Matplotlib tool for measuring teleseismic arrival times. Seismol. Res. Lett. 84, 85–93 (2013).

    Article  Google Scholar 

  57. 57.

    VanDecar, J. C. & Crosson, R. S. Determination of teleseismic relative phase arrival times using multi-channel cross-correlation and least squares. Bull. Seismol. Soc. Am. 80, 150–169 (1990).

    Google Scholar 

  58. 58.

    Kennett, B. L. N. & Engdahl, E. R. Traveltimes for global earthquake location and phase identification. Geophys. J. Int. 105, 429–465 (1991).

    Article  Google Scholar 

  59. 59.

    Laske, G., Masters, G., Ma, Z. & Pasyanos, M. Update on CRUST1.0—a 1-degree global model of Earth’s crust. Geophys. Res. Abstr. 15, 2013–2658 (2013).

    Google Scholar 

Download references


We thank the data centres of the Japanese seismic networks and the JMA Unified Earthquake Catalog for providing the high-quality waveform and arrival-time data used for the study of the Japan subduction zone. P.-L. Wang kindly provided her Cascadia slip model. T. Gou provided his Alaska tomographic model. This work was financially supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB42000000) and the National Natural Science Foundation of China (grant no. 41876043, to J.F.) and the Japan Society for the Promotion of Science (grant no. 19H01996, to D.Z.).

Author information




J.F. and D.Z. conceived this study. J.F. conducted data processing and tomographic inversions. Both authors contributed to the interpretations and preparation of the manuscript.

Corresponding authors

Correspondence to Jianke Fan or Dapeng Zhao.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Geoscience thanks the, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Stefan Lachowycz.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–35.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Fan, J., Zhao, D. Subslab heterogeneity and giant megathrust earthquakes. Nat. Geosci. 14, 349–353 (2021).

Download citation


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing