Skip to main content

Thank you for visiting nature.com. 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.

  • Article
  • Published:

Upper-plate rigidity determines depth-varying rupture behaviour of megathrust earthquakes

Nature volume 576, pages 96–101 (2019)Cite this article

Subjects

Abstract

Seismological data provide evidence of a depth-dependent rupture behaviour of earthquakes occurring at the megathrust fault of subduction zones, also known as megathrust earthquakes1. Relative to deeper events of similar magnitude, shallow earthquake ruptures have larger slip and longer duration, radiate energy that is depleted in high frequencies and have a larger discrepancy between their surface-wave and moment magnitudes1,2,3. These source properties make them prone to generating devastating tsunamis without clear warning signs. The depth-dependent rupture behaviour is usually attributed to variations in fault mechanics4,5,6,7. Conceptual models, however, have so far failed to identify the fundamental physical causes of the contrasting observations and do not provide a quantitative framework with which to predict and link them. Here we demonstrate that the observed differences do not require changes in fault mechanics. We use compressional-wave velocity models from worldwide subduction zones to show that their common underlying cause is a systematic depth variation of the rigidity at the lower part of the upper plate — the rock body overriding the megathrust fault, which deforms by dynamic stress transfer during co-seismic slip. Combining realistic elastic properties with accurate estimates of earthquake focal depth enables us to predict the amount of co-seismic slip (the fault motion at the instant of the earthquake), provides unambiguous estimations of magnitude and offers the potential for early tsunami warnings.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Tectonic structure of the shallow region of two types of subduction zones where tsunamis are generated.
Fig. 2: Convergent margin structure and P-wave velocity at the lower part of overriding plates.
Fig. 3: Predicted earthquake rupture and energy release characteristics.
Fig. 4: Conceptual model of megathrust seismogenic zone domains.

Similar content being viewed by others

Data availability

Source data for Figs. 2 and 3 and for Extended Data Figs. 4–8 are provided with the paper. The digitized values of P-wave seismic velocity above interplate boundary versus depth and seafloor depth along the 48 wide-angle seismic profiles used here are available at the public research data repository figshare (https://doi.org/10.6084/m9.figshare.9729302.v1).

Code availability

The scripts necessary to process the data and reproduce the main results and figures presented in this work are available at the public research data repository figshare (https://doi.org/10.6084/m9.figshare.9729302.v1).

References

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

    ADS  Google Scholar 

  2. Lay, T. & Bilek, S. L. in The Seismogenic Zone of Subduction Thrust Faults (eds. Dixon, T. & Moore, C.) 476–511 (Columbia Univ. Press, 2007).

  3. Bilek, S. L. & Lay, T. Subduction zone megathrust earthquakes. Geosphere 14, 1468–1500 (2018).

    ADS  Google Scholar 

  4. Tobin, H. J. & Saffer, D. M. Elevated fluid pressure and extreme mechanical weakness of a plate boundary thrust, Nankai Trough subduction zone. Geology 37, 679–682 (2009).

    ADS  Google Scholar 

  5. Noda, H. & Lapusta, N. Stable creeping fault segments can become destructive as a result of dynamic weakening. Nature 493, 518–521 (2013).

    ADS  CAS  Google Scholar 

  6. Huang, Y., Meng, L. & Ampuero, J.-P. A dynamic model of the frequency-dependent rupture process of the 2011 Tohoku-Oki earthquake. Earth Planets Space 64, 1061–1066 (2012).

    ADS  Google Scholar 

  7. Ikari, M. J., Kameda, J., Saffer, D. M. & Kopf, A. J. Strength characteristics of Japan Trench borehole samples in the high-slip region of the 2011 Tohoku-oki earthquake. Earth Planet. Sci. Lett. 412, 35–41 (2015).

    ADS  CAS  Google Scholar 

  8. Scholz, C. Earthquakes and friction laws. Nature 391, 37–42 (1998).

    ADS  CAS  Google Scholar 

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

    ADS  CAS  PubMed  Google Scholar 

  10. Maksymowicz, A. et al. Coseismic seafloor deformation in the trench region during the M w8.8 Maule megathrust earthquake. Sci. Rep. 7, 45918 (2017).

    ADS  CAS  PubMed  PubMed Central  Google Scholar 

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

    ADS  Google Scholar 

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

    ADS  Google Scholar 

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

    ADS  Google Scholar 

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

    ADS  Google Scholar 

  15. Geist, E. L. & Bilek, S. L. Effect of depth-dependent shear modulus on tsunami generation along subduction zones. Geophys. Res. Lett. 28, 1315–1318 (2001).

    ADS  Google Scholar 

  16. Bilek, S. L. & Lay, T. Rigidity variations with depth along interplate megathrust faults in subduction zones. Nature 400, 443–446 (1999).

    ADS  CAS  Google Scholar 

  17. von Huene, R., Klaeschen, D., Cropp, B. & Miller, J. Tectonic structure across the accretionary and erosional parts of the Japan Trench margin. J. Geophys. Res. 99, 22, 349–22,361 (1994).

    Google Scholar 

  18. Ranero, C. R. & von Huene, R. Subduction erosion along the Middle America convergent margin. Nature 404, 748–752 (2000).

    ADS  CAS  PubMed  Google Scholar 

  19. Brocher, T. M. Empirical relations between elastic wavespeeds and density in the Earth’s crust. Bull. Seismol. Soc. Am. 95, 2081–2092 (2005).

    Google Scholar 

  20. Allmann, B. P. & Shearer, P. M. Global variations of stress drop for moderate to large earthquakes. J. Geophys. Res. 114, B01310 (2009).

    ADS  Google Scholar 

  21. Bilek, S. L. & Lay, T. Tsunami earthquakes possibly widespread manifestations of frictional conditional stability. Geophys. Res. Lett. 29, 18-1–18-4 (2002).

    Google Scholar 

  22. Pelayo, A. M. & Wiens, D. A. Tsunami earthquakes; slow thrust-faulting events in the accretionary wedge. J. Geophys. Res. 97, 15321–15337 (1992).

    ADS  Google Scholar 

  23. Newman, A. V., Hayes, G., Wei, Y. & Convers, J. The 25 October 2010 Mentawai tsunami earthquake, from real-time discriminants, finite-fault rupture, and tsunami excitation. Geophys. Res. Lett. 38, L05302 (2011).

    ADS  Google Scholar 

  24. 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).

    ADS  CAS  PubMed  PubMed Central  Google Scholar 

  25. Hirono, T. et al. Near-trench slip potential of megaquakes evaluated from fault properties and conditions. Sci. Rep. 6, 28184 (2016).

    ADS  CAS  PubMed  PubMed Central  Google Scholar 

  26. Okal, E. A. & Newman, A. V. Tsunami earthquakes: the quest for a regional signal. Phys. Earth Planet. Inter. 124, 45–70 (2001).

    ADS  Google Scholar 

  27. Abercrombie, R. E., Antolik, M., Felzer, K. & Ekström, G. The 1994 Java tsunami earthquake: slip over a subducting seamount. J. Geophys. Res. 106, 6595–6607 (2001).

    ADS  Google Scholar 

  28. Murphy, S. et al. Shallow slip amplification and enhanced tsunami hazard unravelled by dynamic simulations of mega-thrust earthquakes. Sci. Rep. 6, 35007 (2016).

    ADS  CAS  PubMed  PubMed Central  Google Scholar 

  29. Bilek, S. L. Using earthquake source durations along the Sumatra-Andaman subduction system to examine fault-zone variations. Bull. Seismol. Soc. Am. 97, S62–S70 (2007).

    Google Scholar 

  30. Bilek, S. L., DeShon, H. R. & Engdahl, E. R. Spatial variations in earthquake source characteristics within the 2011 M w = 9.0 Tohoku, Japan rupture zone. Geophys. Res. Lett. 39, L09304 (2012).

    ADS  Google Scholar 

  31. Wang, D. & Mori, J. Frequency-dependent energy radiation and fault coupling for the 2010 M w8.8 Maule, Chile, and 2011 M w9.0 Tohoku, Japan, earthquakes. Geophys. Res. Lett. 38, L22308 (2011).

    ADS  Google Scholar 

  32. Koper, K. D., Hutko, A. R., Lay, T. & Sufri, O. Imaging short-period seismic radiation from the 27 February 2010 Chile (M W8.8) earthquake by back-projection of P, PP, and PKIKP waves. J. Geophys. Res. 117, B02308 (2012).

    ADS  Google Scholar 

  33. Melgar, D. et al. Slip segmentation and slow rupture to the trench during the 2015, M w8.3 Illapel, Chile earthquake. Geophys. Res. Lett. 43, 961–966 (2016).

    ADS  Google Scholar 

  34. Zelt, C. A. & Smith, R. B. Seismic travel time inversion for 2-D crustal velocity structure. Geophys. J. Int. 108, 16–34 (1992).

    ADS  Google Scholar 

  35. Van Avendonk, H. J. A., Harding, A. J., Orcutt, J. A. & McClain, J. S. A two-dimensional tomographic study of the Clipperton transform fault. J. Geophys. Res. 103, 17885–17899 (1998).

    ADS  Google Scholar 

  36. Korenaga, J. et al. Crustal structure of the southeast Greenland margin from joint refraction and reflection seismic tomography. J. Geophys. Res. 105, 21591–21614 (2000).

    ADS  Google Scholar 

  37. Hobro, J. W. D., Singh, S. C. & Minshull, T. A. Three-dimensional tomographic inversion of combined reflection and refraction seismic traveltime data. Geophys. J. Int. 152, 79–93 (2003).

    ADS  Google Scholar 

  38. Contreras-Reyes, E., Grevemeyer, I., Flueh, E. R. & Reichert, C. Upper lithospheric structure of the subduction zone offshore of southern Arauco peninsula, Chile, at 38° S. J. Geophys. Res. 113, B07303 (2008).

    ADS  Google Scholar 

  39. Contreras-Reyes, E. et al. Structure and tectonics of the central Chilean margin (31°–33° S): implications for subduction erosion and shallow crustal seismicity. Geophys. J. Int. 203, 776–791 (2015).

    ADS  Google Scholar 

  40. Sallarès, V. & Ranero, C. R. Structure and tectonics of the erosional convergent margin off Antofagasta, north Chile (23.30° S). J. Geophys. Res. 110, B06101 (2005).

    ADS  Google Scholar 

  41. Sallarès, V. et al. Overriding plate structure of the Nicaragua convergent margin: relationship to the seismogenic zone of the 1992 tsunami earthquake. Geochem. Geophys. Geosyst. 14, 3436–3461 (2013).

    ADS  Google Scholar 

  42. Svetlizky, I. & Fineberg, J. Classical shear cracks drive the onset of dry frictional motion. Nat. Phys. 509, 205–208 (2014).

    CAS  Google Scholar 

  43. Freund, L. B. Dynamic Fracture Mechanics (Cambridge Univ. Press, 1998).

  44. Ambraseys, N. N. & Douglas, J. Near-field horizontal and vertical earthquake ground motions. Soil. Dyn. Earthquake Eng. 23, 1–18 (2003).

    Google Scholar 

  45. Atkinson, G. M. & Boore, D. M. Empirical ground-motion relations for subduction-zone earthquakes and their application to Cascadia and other regions. Bull. Seismol. Soc. Am. 93, 1703–1729 (2003).

    Google Scholar 

  46. Wessel, P., Smith, W. H. F., Scharroo, R., Luis, J. & Wobbe, F. Generic Mapping Tools: improved version released. Eos 94, 409–410 (2013).

    ADS  Google Scholar 

  47. IOC. IHO and BODC, Centenary Edition of the GEBCO Digital Atlas. https://www.gebco.net/data_and_products/gridded_bathymetry_data (2003).

  48. Martinez-Loriente, S. et al. Influence of incoming plate relief on upper plate structure and on earthquake nucleation: the case of Southern Costa Rica. Tectonics (in the press).

  49. Agudelo, W., Ribodetti, A., Collot, J.-Y. & Operto, S. Joint inversion of multichannel seismic reflection and wide-angle seismic data: Improved imaging and refined velocity model of the crustal structure of the north Ecuador–south Colombia convergent margin. J. Geophys. Res. 114, B02306 (2009).

    ADS  Google Scholar 

  50. Contreras-Reyes, E., Becerra, J., Kopp, H., Reichert, C. & Díaz-Naveas, J. Seismic structure of the north-central Chilean convergent margin: Subduction erosion of a paleomagmatic arc. Geophys. Res. Lett. 41, 1523–1529 (2014).

    ADS  Google Scholar 

  51. Moscoso, E. et al. Revealing the deep structure and rupture plane of the 2010 Maule, Chile earthquake (M w = 8.8) using wide angle seismic data. Earth Planet. Sci. Lett. 307, 147–155 (2011).

    ADS  CAS  Google Scholar 

  52. Scherwath, M. et al. Deep lithospheric structures along the southern central Chile margin from wide-angle P-wave modelling. Geophys. J. Int. 179, 579–600 (2009).

    ADS  Google Scholar 

  53. Contreras-Reyes, E. et al. Deep seismic structure of the Tonga subduction zone: implications for mantle hydration, tectonic erosion, and arc magmatism. J. Geophys. Res. 116, B10103 (2011).

    ADS  Google Scholar 

  54. Klingelhoefer, F. et al. Limits of the seismogenic zone in the epicentral region of the 26 December 2004 great Sumatra-Andaman earthquake: Results from seismic refraction and wide-angle reflection surveys and thermal modeling. J. Geophys. Res. 115, B01304 (2010).

    ADS  Google Scholar 

  55. Arai, R. et al. Structure of the tsunamigenic plate boundary and low-frequency earthquakes in the southern Ryukyu Trench. Nat. Commun. 7, 12255 (2016).

  56. Kodaira, S., Takahashi, N., Nakanishi, A., Miura, S. & Kaneda, Y. Subducted seamount imaged in the rupture zone of the 1946 Nankaido earthquake. Science 289, 104–106 (2000).

    ADS  CAS  PubMed  Google Scholar 

  57. Nakamura, Y. et al. Seismic imaging and velocity structure around the JFAST drill site in the Japan Trench: low Vp, high Vp/Vs in the transparent frontal prism. Earth Planets Space 66, 121 (2014).

    ADS  Google Scholar 

  58. Horning, G. et al. 2-D tomographic model of the Juan de Fuca plate from accretion at axial seamount to subduction at the Cascadia margin from an active source ocean bottom seismometer survey. J. Geophys. Res. 121, 5859–5879 (2016).

    ADS  Google Scholar 

  59. Krabbenhöft, A., Bialas, J., Kopp, H., Kukowski, N. & Hübscher, C. Crustal structure of the Peruvian continental margin from wide-angle seismic studies. Geophys. J. Int. 159, 749–764 (2004).

    ADS  Google Scholar 

  60. Hampel, A., Kukowski, N., Bialas, J., Huebscher, C. & Heinbockel, R. Ridge subduction at an erosive margin: the collision zone of the Nazca Ridge in southern Peru. J. Geophys. Res. 109, B02101 (2004).

    ADS  Google Scholar 

  61. Shulgin, A. et al. Structural architecture of oceanic plateau subduction offshore Eastern Java and the potential implications for geohazards. Geophys. J. Int. 184, 12–28 (2011).

    ADS  Google Scholar 

  62. Bassett, D. et al. Three dimensional velocity structure of the northern Hikurangi margin, Raukumara, New Zealand: implications for the growth of continental crust by subduction erosion and tectonic underplating. Geochem. Geophys. Geosyst. 11, Q10013 (2010).

    ADS  Google Scholar 

  63. Miura, S. et al. Seismological structure and implications of collision between the Ontong Java Plateau and Solomon Island Arc from ocean bottom seismometer-airgun data. Tectonophysics 389, 191–220 (2004).

    ADS  CAS  Google Scholar 

  64. Takahashi, N., Suyehiro, K. & Shinohara, M. Implications from the seismic crustal structure of the northern Izu–Bonin arc. Isl. Arc 7, 383–394 (1998).

    Google Scholar 

  65. Walther, C. H. E., Flueh, E. R., Ranero, C. R., von Huene, R. & Strauch, W. Crustal structure across the Pacific margin of Nicaragua: evidence for ophiolitic basement and a shallow mantle sliver. Geophys. J. Int. 141, 759–777 (2000).

    ADS  Google Scholar 

  66. Sallarès, V., Dañobeitia, J. J. & Flueh, E. Lithospheric structure of the Costa Rican Isthmus: effects of subduction zone magmatism on an oceanic plateau. J. Geophys. Res. 106, 621–643 (2001).

    ADS  Google Scholar 

  67. Bassett, D. et al. Crustal structure of the Kermadec arc from MANGO seismic refraction profiles. J. Geophys. Res. 121, 7514–7546 (2016).

    ADS  Google Scholar 

  68. Klingelhoefer, F. et al. P-wave velocity structure of the southern Ryukyu margin east of Taiwan: results from the ACTS wide-angle seismic experiment. Tectonophysics 578, 50–62 (2012).

    ADS  Google Scholar 

  69. Kopp, H., Klaeschen, D., Flueh, E. R., Bialas, J. & Reichert, C. Crustal structure of the Java margin from seismic wide-angle and multichannel reflection data. J. Geophys. Res. 107, ETG 1-1–ETG 1-24 (2002).

    Google Scholar 

  70. Planert, L. et al. Lower plate structure and upper plate deformational segmentation at the Sunda–Banda arc transition, Indonesia. J. Geophys. Res. 115, B08107 (2010).

    ADS  Google Scholar 

  71. Ye, S., Flueh, E. R., Klaeschen, D. & von Huene, R. Crustal structure along the EDGE transect beneath the Kodiak shelf off Alaska derived from OBH seismic refraction data. Geophys. J. Int. 130, 283–302 (1997).

    ADS  Google Scholar 

  72. Nakanishi, A. et al. Crustal evolution of the southwestern Kuril Arc, Hokkaido Japan, deduced from seismic velocity and geochemical structure. Tectonophysics 472, 105–123 (2009).

    ADS  CAS  Google Scholar 

  73. Nakanishi, A. et al. Crustal structure across the coseismic rupture zone of the 1944 Tonankai earthquake, the central Nankai Trough seismogenic zone. J. Geophys. Res. 107, EPM 2-1–EPM 2-21 (2002).

    Google Scholar 

  74. Kodaira, S. et al. Western Nankai Trough seismogenic zone: results from a wide-angle ocean bottom seismic survey. J. Geophys. Res. 105, 5887–5905 (2000).

    ADS  Google Scholar 

  75. Singh, S. C. et al. Seismic evidence of bending and unbending of subducting oceanic crust and the presence of mantle megathrust in the 2004 Great Sumatra earthquake rupture zone. Earth Planet. Sci. Lett. 321–322, 166–176 (2012).

    ADS  Google Scholar 

  76. Kopp, H. et al. Deep structure of the central Lesser Antilles Island Arc: relevance for the formation of continental crust. Earth Planet. Sci. Lett. 304, 121–134 (2011).

    ADS  CAS  Google Scholar 

  77. Zhu, J. et al. Crustal structure of the central Costa Rica subduction zone: implications for basal erosion from seismic wide-angle data. Geophys. J. Int. 178, 1112–1131 (2009).

    ADS  Google Scholar 

  78. Begovic, S., Ranero, C. R., Sallarès, V. &  Grevemeyer, I.  2D velocity and interplate geometry model of the North Chile margin from joint refraction and  wide-angle reflection travel time inversion. In Subduction Interface Processes (SIP) Int. Conf. (2017). 

  79. Graindorge, D., Calahorrano, A., Charvis, P., Collot, J.-Y. & Bethoux, N. Deep structures of the Ecuador convergent margin and the Carnegie Ridge, possible consequence on great earthquakes recurrence interval. Geophys. Res. Lett. 31, L04603 (2004).

    ADS  Google Scholar 

  80. Gailler, A., Charvis, P. & Flueh, E. R. Segmentation of the Nazca and South American plates along the Ecuador subduction zone from wide angle seismic profiles. Earth Planet. Sci. Lett. 260, 444–464 (2007).

    ADS  CAS  Google Scholar 

  81. Krabbenhoeft, A., von Huene, R., Klaeschen, D. & Miller, J. J. Subduction-related structure in the M w 9.2, 1964 megathrust rupture area offshore Kodiak Island, Alaska. In AGU Fall Meet. https://ui.adsabs.harvard.edu/abs/2016AGUFM.T11D2641K/abstract (2016).

  82. Miura, S. et al. Structural characteristics off Miyagi forearc region, the Japan Trench seismogenic zone, deduced from wide-angle reflection and refraction study. Tectonophysics 407, 165–188 (2005).

    ADS  Google Scholar 

  83. Nishizawa, A. et al. Variations in seismic velocity distribution along the Ryukyu (Nansei-Shoto) Trench subduction zone at the northwestern end of the Philippine Sea plate. Earth Planets Space https://doi.org/10.1186/s40623-017-0674-7 (2017).

  84. Barrientos, S. E. & Ward, S. N. The 1960 Chile earthquake: inversion for slip distribution from surface deformation. Geophys. J. Int. 103, 589–598 (1990).

    ADS  Google Scholar 

  85. Kanamori, H. The Alaska Earthquake of 1964: radiation of long-period surface waves and source mechanism. J. Geophys. Res. 75, 5029–5040 (1970).

    ADS  Google Scholar 

  86. Lay, T. et al. The great Sumatra–Andaman earthquake of 26 December 2004. Science 308, 1127–1133 (2005).

    ADS  CAS  PubMed  Google Scholar 

  87. Koketsu, K. et al. A unified source model for the 2011 Tohoku earthquake. Earth Planet. Sci. Lett. 310, 480–487 (2011).

    ADS  CAS  Google Scholar 

  88. Delouis, B., Nocquet, J.-M. & Vallée, M. Slip distribution of the February 27, 2010 M w = 8.8 Maule Earthquake, central Chile, from static and high-rate GPS, InSAR, and broadband teleseismic data. Geophys. Res. Lett. 37, L17305 (2010).

    ADS  Google Scholar 

  89. Wu, F. T. & Kanamori, H. Source mechanism of February 4, 1965, Rat Island earthquake. J. Geophys. Res. 78, 6082–6092 (1973).

    ADS  Google Scholar 

  90. Ihmlé, P. F., Gómez, J.-M., Heinrich, Ph. & Guibourg, S. The 1996 Peru tsunamigenic earthquake: broadband source process. Geophys. Res. Lett. 25, 2691–2694 (1998).

    ADS  Google Scholar 

  91. Bell, R., Holden, C., Power, W., Wang, X. & Downes, G. Hikurangi margin tsunami earthquake generated by slow seismic rupture over a subducted seamount. Earth Planet. Sci. Lett. 397, 1–9 (2014).

    ADS  CAS  Google Scholar 

  92. Newman, A. V. et al. The energetic 2010 M w 7.1 Solomon Island tsunami earthquake. Geophys. J. Int. 186, 775–781 (2011).

    ADS  Google Scholar 

  93. Ammon, C. J., Kanamori, H., Lay, T. & Velasco, A. A. The 17 July 2006 Java tsunami earthquake. Geophys. Res. Lett. 33, L24308 (2006).

    ADS  Google Scholar 

  94. Tanioka, T. & Satake, K. Fault parameters of the 1896 Sanriku tsunami earthquake estimated from tsunami numerical modeling. Geophys. Res. Lett. 23, 1549–1552 (1996).

    ADS  Google Scholar 

  95. Johnson, J. M. & Satake, K. Estimation of seismic moment and slip distribution of the April 1, 1946, Aleutian tsunami earthquake. J. Geophys. Res. 102, 11765–11774 (1997).

    ADS  Google Scholar 

Download references

Acknowledgements

This work was done in the framework of projects ZIP (reference 604713), funded by the E.C. in the call for proposals FP7-PEOPLE-2013-ITN and FRAME (reference CTM2015-71766-R), funded by the Spanish Plan of Research and Innovation. We thank D. Klaeschen and R. von Huene (Geomar) for providing a copy of the P849 seismic data displayed in Fig. 1, T. Lay for his review, and J.-P. Ampuero for his comments on a preliminary version of the work.

Author information

Authors and Affiliations

  1. Barcelona Center for Subsurface Imaging, Institute of Marine Sciences, CSIC, Barcelona, Spain

    Valentí Sallarès & César R. Ranero

  2. ICREA, Barcelona, Spain

    César R. Ranero

Authors
  1. Valentí Sallarès
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. César R. Ranero
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

V.S. had the original idea, conceived the physical model, selected and digitized the P-wave velocity profiles, performed the calculations, made the figures except Fig. 1, and wrote the first draft of the manuscript. C.R.R. made the geological interpretation of the physical model, contributed to identifying its implications, processed and pre-stack depth-migrated Java 07 and interpreted both seismic images on Fig. 1, and contributed to writing the manuscript.

Corresponding author

Correspondence to Valentí Sallarès.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

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

Peer review information Nature thanks Thorne Lay and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Extended data figures and tables

Extended Data Fig. 1 Location map of seismic profiles and recent great and tsunami earthquakes.

Colour-coded relief map of seafloor (blue-green) and emerged land (grey). Circles indicate location of the trench-crossing refraction and wide-angle reflection seismic (WAS) profiles used in this study. Yellow-filled circles are in erosional margins and red-filled circles in accretionary margins. The location, type of margin and references for all profiles are listed in Extended Data Table 1. Numbered white stars show locations of 12 events recognized as tsunami earthquakes according to the definition of Kanamori11: (1) Mw 7.6, 1992 Nicaragua; (2) Mw 7.6, 1960 Peru; (3) Mw 7.5, 1995 Peru; (4) Ms 7.2, 1947 Hikurangi; (5) Mw 7.1, 2010 Solomon; (6) Mw 7.6, 1994 Java; (7) Mw 7.8, 2006 Java; (8) Mw 7.8, 2010 Mentawai; (9) Mw 8.0, 1896 Sanriku; (10) Mw 7.5, 1975 Kurile; (11) Mw 7.8, 1963 Kurile; (12) Mw 8.2, 1946 Aleutian. Orange polygons display the rupture areas of the six largest megathrust earthquakes since 1960: Mw 9.5, 1960 Valdivia; Mw 9.2, 1964 Alaska; Mw 9.1, 2004 Andaman Islands; Mw 9.1, 2010 Tohoku-Oki; Mw 8.8, 2010 Maule; Mw 8.7, 1965 Rat Island. Hypocentral location, date, magnitude and references for all these earthquakes are listed in Extended Data Table 2. This figure has been created using the GMT software package46. The topographic and bathymetric relief data have been taken from the GEBCO Digital Atlas data set47. Authors are not aware of any disputed territories shown.

Extended Data Fig. 2 Superposition of multichannel seismic image and P-wave velocity model.

Example of superposition of a VP model (colour, see scale) on a spatially coincident multichannel seismic image (shading) along profile NIC-20, acquired in the convergent margin of Nicaragua. This profile crosses the rupture area of the 1992 Nicaragua tsunami earthquake (Extended Data Fig. 1). Black lines show isovelocity contours with their corresponding velocity values. White circles indicate the approximate location of the interplate boundary, where megathrust earthquakes take place.

Extended Data Fig. 3 Resolution of VP models and wavelength of rupture stress wavefield.

The light red polygon displays the width of the Fresnel zone as a function of depth, assuming VP(z) in Fig. 2a and energy sources with minimum (maximum) peak frequency fs = 8 Hz (12 Hz). The blue-lilac polygon indicates the approximate wavelength of the stress wavefield associated to earthquake rupture propagation (λw), assuming VS(z) in Extended Data Fig. 5c as propagation velocity, and near-field ground motion spectra with minimum (maximum) peak frequency fsw = 1 Hz (4 Hz) (see Methods for details).

Extended Data Fig. 4 Physical properties versus interplate boundary depth.

a, Red (yellow) circles show VP as a function of z. It is obtained by averaging digitized VP values of accretionary and erosional margins (red and yellow circles, respectively, in Fig. 2b). b, White circles show density (ρ) just above the interplate boundary, as a function of z, obtained by applying Brocher’s ρ(VP) relationship19. c, Red circles show shear-wave velocity (VS) just above the interplate boundary, as a function of z, obtained by applying the VS(VP) relationship from Brocher (ref. 19). The shaded polygon covers the range of possible mode III rupture velocities, as a function of z, according to field observations: u(z) = (0.7–0.9)VS(z). The black line is a fourth-order polynomial regression fit of the VP(z), ρ(z) and VS(z) values, respectively. The size of the error bars in all cases is one standard deviation.

Source data

Extended Data Fig. 5 P-wave velocity and rigidity gradients.

a, Red line shows the depth gradient of VP as a function of interplate boundary depth, \(\partial {V}_{{\rm{P}}}(z)/\partial z\). It corresponds to the derivative of the VP(z) polynomial regression fit (black line in Fig. 2c). b, Blue line shows the depth gradient of μ as a function of interplate boundary depth, \(\partial \mu (z)/\partial z\). It corresponds to the derivative of the μ(z) polynomial regression fit (black line in Fig. 2d).

Source data

Extended Data Fig. 6 Corner frequency and moment rate spectra.

a, Coloured circles show corner frequency as a function of interplate boundary depth (z), for events of Mw = 5.8-8.6. Δσ = 3 MPa is used in the calculations, and VS(z) is taken from Extended Data Fig. 3c. The colour scale indicates Mw. b, Solid lines show calculated moment rate spectra for three events of Mw = 6.4 (bottom), 7.4 (mid) and 8.4 (top). Black, blue and red lines correspond to Vs at z = 1 km, 6 km and 25 km, respectively, for each event. Coloured circles indicate corner frequency according to colour code in Extended Data Fig. 6a. Vertical dashed lines indicate periods of 250 s and 20 s, reference to calculate Mw and Ms, respectively. In all cases, note the high-frequency depletion at shallow depths.

Source data

Extended Data Fig. 7 Source duration of circum-Pacific megathrust earthquakes.

a, White circles show scaled source duration of 525 moderate size (Mw 5.0–7.5) shallow megathrust subduction earthquakes from around the circum-Pacific, as a function of depth. Black circles show the same source parameters for six large tsunami earthquakes. Data are from ref. 21. This article contains all the information on the procedure followed to calculate the source parameters. b, Red circles are the normalized source duration in a averaged within a 2-km-thick sliding window. Blue circles correspond to relative rupture duration in Fig. 3b scaled to fit average normalized rupture duration within the regular domain in a (approximately 3.5 s), and shifted 4.5 km down to compensate for the difference between depth below sea surface and depth below seafloor. Error bars are one standard deviation.

Source data

Extended Data Fig. 8 Range of variation of Mw for a given Ms.

White circles show Mw for events occurring at different interplate boundary depth b.s. that have the same spectral amplitude at 20 s (hence equivalent Ms).

Source data

Extended Data Table 1 Location of seismic profiles and margin type
Full size table
Extended Data Table 2 Location and magnitude of circum-Pacific megathrust earthquakes
Full size table

Source data

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Sallarès, V., Ranero, C.R. Upper-plate rigidity determines depth-varying rupture behaviour of megathrust earthquakes. Nature 576, 96–101 (2019). https://doi.org/10.1038/s41586-019-1784-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41586-019-1784-0

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

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