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.

Rheological separation of the megathrust seismogenic zone and episodic tremor and slip


Episodic tremor and accompanying slow slip, together called ETS, is most often observed in subduction zones of young and warm subducting slabs1,2,3. ETS should help us to understand the mechanics of subduction megathrusts3,4, but its mechanism is still unclear. It is commonly assumed that ETS represents a transition from seismic to aseismic behaviour of the megathrust with increasing depth, but this assumption is in contradiction with an observed spatial separation between the seismogenic zone and the ETS zone5,6,7,8. Here we propose a unifying model for the necessary geological condition of ETS that explains the relationship between the two zones. By developing numerical thermal models, we examine the governing role of thermo-petrologically controlled fault zone rheology (frictional versus viscous shear). High temperatures in the warm-slab environment9 cause the megathrust seismogenic zone to terminate before reaching the depth of the intersection of the continental Mohorovičić discontinuity (Moho) and the subduction interface, called the mantle wedge corner. High pore-fluid pressures around the mantle wedge corner10 give rise to an isolated friction zone responsible for ETS. Separating the two zones is a segment of semi-frictional or viscous behaviour. The new model reconciles a wide range of seemingly disparate observations and defines a conceptual framework for the study of slip behaviour and the seismogenesis of major faults.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Observed relationship between the seismogenic zone and the ETS zone in Nankai.
Figure 2: Schematic illustration of fault stress and slip phenomena for subduction zones that produce great earthquakes and ETS.
Figure 3: Models of megathrust rheology for warm-slab subduction zones Nankai, Northern Cascadia and Mexico, and cold-slab subduction zones Japan Trench and Hikurangi.
Figure 4: Rheologically controlled slip phenomena along the San Andreas Fault.


  1. 1

    Rogers, G. & Dragert, H. Episodic tremor and slip on the Cascadia subduction zone: the chatter of silent slip. Science 300, 1942–1943 (2003)

    ADS  CAS  PubMed  Google Scholar 

  2. 2

    Shelly, D. R., Beroza, G. C., Ide, S. & Nakamula, S. Low-frequency earthquakes in Shikoku, Japan, and their relationship to episodic tremor and slip. Nature 442, 188–191 (2006)

    ADS  CAS  PubMed  Google Scholar 

  3. 3

    Peng, Z. & Gomberg, J. An integrated perspective of the continuum between earthquakes and slow-slip phenomena. Nat. Geosci. 3, 599–607 (2010)

    ADS  CAS  Google Scholar 

  4. 4

    Ide, S., Beroza, G. C., Shelly, D. R. & Uchide, T. A scaling law for slow earthquakes. Nature 447, 76–79 (2007)

    ADS  CAS  PubMed  Google Scholar 

  5. 5

    Obara, K. Characteristics and interactions between non-volcanic tremor and related slow earthquakes in the Nankai subduction zone, southwest Japan. J. Geodyn. 52, 229–248 (2011)

    Google Scholar 

  6. 6

    Husker, A. L. et al. Temporal variations of non-volcanic tremor (NVT) locations in the Mexican subduction zone: finding the NVT sweet spot. Geochem. Geophys. Geosyst. 13, Q03011 (2012)

    ADS  Google Scholar 

  7. 7

    Hyndman, R. D., McCrory, P. A., Wech, A., Kao, H. & Ague, J. Cascadia subducting plate fluids channelled to fore-arc mantle corner: ETS and silica deposition. J. Geophys. Res. 120, 4344–4358 (2015)

    ADS  Google Scholar 

  8. 8

    Wang, K. & Tréhu, A. M. Some outstanding issues in the study of great megathrust earthquakes—The Cascadia example. J. Geodyn. 98, 1–18 (2016)

    Google Scholar 

  9. 9

    Wada, I. & Wang, K. Common depth of slab-mantle decoupling: reconciling diversity and uniformity of subduction zones. Geochem. Geophys. Geosyst. 10, Q10009 (2009)

    ADS  Google Scholar 

  10. 10

    Audet, P. & Kim, Y. H. Teleseismic constraints on the geological environment of deep episodic slow earthquakes in subduction zone forearcs: a review. Tectonophysics 670, 1–15 (2016)

    ADS  Google Scholar 

  11. 11

    Schwartz, S. Y. & Rokosky, J. M. Slow slip events and seismic tremor at circum-Pacific subduction zones. Rev. Geophys. 45, 1–32 (2007)

    Google Scholar 

  12. 12

    Liu, Y. & Rice, J. R. Slow slip predictions based on granite and gabbro friction data compared to GPS measurements in northern Cascadia. J. Geophys. Res. 114, B09407 (2009)

    ADS  Google Scholar 

  13. 13

    Dragert, H., Wang, K. & Rogers, G. A silent slip event on the deeper cascadia subduction interface. Science 292, 1525–1528 (2001)

    ADS  CAS  PubMed  Google Scholar 

  14. 14

    Obara, K. Nonvolcanic deep tremor associated with subduction in southwest Japan. Science 296, 1679–1681 (2002)

    ADS  CAS  PubMed  Google Scholar 

  15. 15

    Shimamoto, T. & Noda, H. A friction to flow constitutive law and its application to a 2-D modeling of earthquakes. J. Geophys. Res. 119, 8089–8106 (2014)

    ADS  Google Scholar 

  16. 16

    Angiboust, S. et al. Probing the transition between seismically coupled and decoupled segments along an ancient subduction interface. Geochem. Geophys. Geosyst. 16, 1905–1922 (2015)

    ADS  Google Scholar 

  17. 17

    Matsuzawa, T., Hirose, H., Shibazaki, B. & Obara, K. Modeling short- and long-term slow slip events in the seismic cycles of large subduction earthquakes. J. Geophys. Res. 115, B12301 (2010)

    ADS  Google Scholar 

  18. 18

    Johnson, K. M., Shelly, D. R. & Bradley, A. M. Simulations of tremor-related creep reveal a weak crustal root of the San Andreas Fault. Geophys. Res. Lett. 40, 1300–1305 (2013)

    ADS  Google Scholar 

  19. 19

    Wada, I., Wang, K., He, J. & Hyndman, R. D. Weakening of the subduction interface and its effects on surface heat flow, slab dehydration, and mantle wedge serpentinization. J. Geophys. Res. 113, B04402 (2008)

    ADS  Google Scholar 

  20. 20

    Audet, P. & Bürgmann, R. Possible control of subduction zone slow-earthquake periodicity by silica enrichment. Nature 510, 389–392 (2014)

    ADS  CAS  PubMed  Google Scholar 

  21. 21

    Giger, S. B., Tenthorey, E., Cox, S. F. & Fitz Gerald, J. D. Permeability evolution in quartz fault gouges under hydrothermal conditions. J. Geophys. Res. 112, B07202 (2007)

    ADS  Google Scholar 

  22. 22

    Dempsey, D. E., Rowland, J. V., Zyvoloski, G. A. & Archer, R. A. Modeling the effects of silica deposition and fault rupture on natural geothermal systems. J. Geophys. Res. 117, B05207 (2012)

    ADS  Google Scholar 

  23. 23

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

    ADS  CAS  PubMed  Google Scholar 

  24. 24

    Di Toro, G. et al. Fault lubrication during earthquakes. Nature 471, 494–498 (2011)

    ADS  CAS  PubMed  Google Scholar 

  25. 25

    Nakamura, W., Uchida, N. & Matsuzawa, T. Spatial distribution of the faulting types of small earthquakes around the 2011 Tohoku-oki earthquake: a comprehensive search using template events. J. Geophys. Res. 121, 1–17 (2016)

    Google Scholar 

  26. 26

    Wang, K. & Bilek, S. L. Fault creep caused by subduction of rough seafloor relief. Tectonophysics 610, 1–24 (2014)

    ADS  Google Scholar 

  27. 27

    Saffer, D. M. & Wallace, L. M. The frictional, hydrologic, metamorphic and thermal habitat of shallow slow earthquakes. Nat. Geosci. 8, 594–600 (2015)

    ADS  CAS  Google Scholar 

  28. 28

    Kirby, S. H., Wang, K. & Brocher, T. M. A large mantle water source for the northern San Andreas fault system: a ghost of subduction past. Earth Planets Space 66, 67 (2014)

    ADS  Google Scholar 

  29. 29

    Hirauchi, K., den Hartog, S. A. M. & Spiers, C. J. Weakening of the slab–mantle wedge interface induced by metasomatic growth of talc. Geology 41, 75–78 (2013)

    ADS  CAS  Google Scholar 

  30. 30

    Daub, E. G., Shelly, D. R., Guyer, R. A. & Johnson, P. A. Brittle and ductile friction and the physics of tectonic tremor. Geophys. Res. Lett. 38, L10301 (2011)

    ADS  Google Scholar 

  31. 31

    Igarashi, T., Matsuzawa, T. & Hasegawa, A. Repeating earthquakes and interplate aseismic slip in the northeastern Japan subduction zone. J. Geophys. Res. 108, 2249 (2003)

    ADS  Google Scholar 

  32. 32

    Bachmann, R. et al. Exposed plate interface in the European Alps reveals fabric styles and gradients related to an ancient seismogenic coupling zone. J. Geophys. Res. 114, B05402 (2009)

    ADS  Google Scholar 

  33. 33

    Wang, P.-L. et al. Heterogeneous rupture in the great Cascadia earthquake of 1700 inferred from coastal subsidence estimates. J. Geophys. Res. 118, 1–14 (2013)

    Google Scholar 

  34. 34

    Payero, J. S. et al. Nonvolcanic tremor observed in the Mexican subduction zone. Geophys. Res. Lett. 35, L07305 (2008)

    ADS  Google Scholar 

  35. 35

    Frank, W. B. et al. Using systematically characterized low-frequency earthquakes as a fault probe in Guerrero, Mexico. J. Geophys. Res. 119, 7686–7700 (2014)

    ADS  Google Scholar 

  36. 36

    McCrory, P. A., Constantz, J. E., Hunt, A. G. & Blair, J. L. Helium as a tracer for fluids released from Juan de Fuca lithosphere beneath the Cascadia forearc. Geochem. Geophys. Geosyst. 17, 2434–2449 (2016)

    ADS  CAS  Google Scholar 

  37. 37

    Song, T. R. A. et al. Subducting slab ultra-slow velocity layer coincident with silent earthquakes in southern Mexico. Science 324, 502–506 (2009)

    ADS  CAS  PubMed  Google Scholar 

  38. 38

    Kim, Y., Clayton, R. W. & Jackson, J. M. Geometry and seismic properties of the subducting Cocos plate in central Mexico. J. Geophys. Res. 115, B06310 (2010)

    ADS  Google Scholar 

  39. 39

    Eberhart-Phillips, D. & Bannister, S. 3-D imaging of the northern Hikurangi subduction zone, New Zealand: variations in subducted sediment, slab fluids and slow slip. Geophys. J. Int. 201, 838–855 (2015)

    ADS  Google Scholar 

  40. 40

    Thomas, A. M., Nadeau, R. M. & Bürgmann, R. Tremor-tide correlations and near-lithostatic pore pressure on the deep San Andreas Fault. Nature 462, 1048–1051 (2009)

    ADS  CAS  PubMed  Google Scholar 

  41. 41

    Nadeau, R. M. & Guilhem, A. Nonvolcanic tremor evolution and the San Simeon and Parkfield, California, earthquakes. Science 325, 191–193 (2009)

    ADS  CAS  PubMed  Google Scholar 

  42. 42

    Beeler, N. M., Thomas, A., Bürgmann, R. & Shelly, D. R. Inferring fault rheology from low-frequency earthquakes on the San Andreas. J. Geophys. Res. 118, 5976–5990 (2013)

    ADS  Google Scholar 

  43. 43

    Zeng, X. et al. 3-D P- and S-wave velocity structure and low-frequency earthquake locations in the Parkfield, California region. Geophys. J. Int. 206, 1574–1585 (2016)

    ADS  Google Scholar 

  44. 44

    Becken, M., Ritter, O., Bedrosian, P. A. & Weckmann, U. Correlation between deep fluids, tremor and creep along the central San Andreas fault. Nature 480, 87–90 (2011)

    ADS  CAS  PubMed  Google Scholar 

  45. 45

    Tietze, K. & Ritter, O. Three-dimensional magnetotelluric inversion in practice—the electrical conductivity structure of the San Andreas Fault in Central California. Geophys. J. Int. 195, 130–147 (2013)

    ADS  Google Scholar 

  46. 46

    Sass, J. H., Williams, C. F., Lachenbruch, A. H., Galanis, S. P., Jr & Grubb, F. V. Thermal regime of the San Andreas Fault near Parkfield, California. J. Geophys. Res. 102, 27575–27585 (1997)

    ADS  Google Scholar 

  47. 47

    Williams, C. F., Grubb, F. V. & Galanis, S. P. Jr. Heat flow in the SAFOD pilot hole and implications for the strength of the San Andreas Fault. Geophys. Res. Lett. 31, L15S14 (2004)

    Google Scholar 

  48. 48

    Fulton, P. M. & Saffer, D. M. Potential role of mantle-derived fluids in weakening the San Andreas Fault. J. Geophys. Res. 114, B07408 (2009)

    ADS  Google Scholar 

  49. 49

    Fulton, P. M., Saffer, D. M., Harris, R. N. & Bekins, B. A. Re-evaluation of heat flow data near Parkfield, CA: evidence for a weak San Andreas Fault. Geophys. Res. Lett. 31, L15S15 (2004)

    Google Scholar 

  50. 50

    Zhu, L. Crustal structure across the San Andreas Fault, southern California from teleseismic converted waves. Earth Planet. Sci. Lett. 179, 183–190 (2000)

    ADS  CAS  Google Scholar 

  51. 51

    Yamanaka, Y. & Kikuchi, M. Asperity map along the subduction zone in northeastern Japan inferred from regional seismic data. J. Geophys. Res. 109, B07307 (2004)

    ADS  Google Scholar 

  52. 52

    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)

    ADS  Google Scholar 

  53. 53

    Wallace, L. M. et al. Characterizing the seismogenic zone of a major plate boundary subduction thrust: Hikurangi Margin, New Zealand. Geochem. Geophys. Geosyst. 10, Q10006 (2009)

    ADS  Google Scholar 

  54. 54

    Okino, K., Shimakawa, Y. & Nagaoka, S. Evolution of the Shikoku Basin. J. Geomag. Geoelectr. 46, 463–479 (1994)

    ADS  Google Scholar 

  55. 55

    Wilson, D. Tectonic history of the Juan de Fuca ridge over the last 40 million years. J. Geophys. Res. 93, 11863–11876 (1988)

    ADS  Google Scholar 

  56. 56

    Kostoglodov, V. & Bandy, W. Seismotectonic constraints on the convergence rate between the Rivera and North American plates. J. Geophys. Res. 100, 17977–17989 (1995)

    ADS  Google Scholar 

  57. 57

    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)

    ADS  Google Scholar 

  58. 58

    Loveless, J. P. & Meade, B. J. Geodetic imaging of plate motions, slip rates, and partitioning of deformation in Japan. J. Geophys. Res. 115, B02410 (2010)

    ADS  Google Scholar 

  59. 59

    DeMets, C., Gordon, R. G. & Argus, D. F. Geologically current plate motions. Geophys. J. Int. 181, 1–80 (2010)

    ADS  Google Scholar 

  60. 60

    Altamimi, Z., Collilieux, X., Legrand, J., Garayt, B. & Boucher, C. ITRF2005: A new release of the International Terrestrial Reference Frame based on time series of station positions and Earth Orientation Parameters. J. Geophys. Res. 112, B09401 (2007)

    ADS  Google Scholar 

  61. 61

    Nakanishi, A. et al. Crustal struture across the coseismic rupture zone of the 1994 Tonankai earthquake, the central Nankai Trough seismogenic zone. J. Geophys. Res. 107, (2002)

  62. 62

    Bostock, M. G., Hyndman, R. D., Rondenay, S. & Peacock, S. M. An inverted continental Moho and serpentinization of the forearc mantle. Nature 417, 536–538 (2002)

    ADS  CAS  PubMed  Google Scholar 

  63. 63

    Kim, Y., Miller, M. S., Pearce, F. & Clayton, R. W. Seismic imaging of the Cocos plate subduction zone system in central Mexico. Geochem. Geophys. Geosyst. 13, Q07001 (2012)

    ADS  Google Scholar 

  64. 64

    Nakajima, J., Matsuzawa, T. & Kasegawa, A. Moho depth variation in the central part of northeastern Japan estimated from reflected and converted waves. Phys. Earth Planet. Inter. 130, 31–47 (2002)

    ADS  Google Scholar 

  65. 65

    Bannister, S., Bryan, C. J. & Bibby, H. M. Shear wave velocity variation across the Taupo Volcanic zone, New Zealand, from receiver function inversion. Geophys. J. Int. 159, 291–310 (2004)

    ADS  Google Scholar 

  66. 66

    Wang, K., Wada, I. & Ishikawa, Y. Stresses in the subduction slab beneath southwest Japan and relation with plate geometry, tectonic forces, slab dehydration, and damaging earthquakes. J. Geophys. Res. 109, B08304 (2004)

    ADS  Google Scholar 

  67. 67

    Davis, E. E., Hyndman, R. D. & Villinger, H. Rates of fluid expulsion across the northern Cascadia accretionary prism constraints from new heat flow and multichannel seismic reflection data. J. Geophys. Res. 95, 8869–8889 (1990)

    ADS  Google Scholar 

  68. 68

    Hayes, G. P., Wald, D. J. & Johnson, R. L. Slab1.0: a three-dimensional model of global subduction zone geometries. J. Geophys. Res. 117, B01302 (2012)

    ADS  Google Scholar 

  69. 69

    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)

    ADS  CAS  Google Scholar 

  70. 70

    Williams, C. A. et al. Revised interface geometry for the Hikurangi subduction zone, New Zealand. Seismol. Res. Lett. 84, 1066–1073 (2013)

    Google Scholar 

  71. 71

    Ichinose, G. A., Thio, H. K., Somerville, P. G., Sato, T. & Ishii, T. Rupture process of the 1944 Tonankai earthquake (Ms 8.1) from the inversion of teleseismic and regional seismograms. J. Geophys. Res. 108, 2497 (2003)

    ADS  Google Scholar 

  72. 72

    Baba, T. & Cummins, P. R. Contiguous rupture areas of two Nankai Trough earthquakes revealed by high-resolution tsunami waveform inversion. Geophys. Res. Lett. 32, L08305 (2005)

    ADS  Google Scholar 

  73. 73

    Baba, T., Cummins, P. R., Hori, T. & Kaneda, Y. High precision slip distribution of the 1944 Tonankai earthquake inferred from tsunami waveforms: possible slip on a splay fault. Tectonophysics 426, 119–134 (2006)

    ADS  Google Scholar 

  74. 74

    Kostoglodov, V. & Pacheco, J. F. Cien Anˇ os de Sismicidad en Míxico (Instituto de Geofísica, Universidad Nacional Autónoma de México, 1999)

  75. 75

    Murray, J. & Langbein, J. Slip on the San Andreas Fault at Parkfield, California, over two earthquake cycles, and the implications for seismic hazard. Bull. Seismol. Soc. Am. 96, S283–S303 (2006)

    Google Scholar 

  76. 76

    Waldhauser, F. & Schaff, D. P. Large-scale relocation of two decades of northern California seismicity using cross-correlation and double-difference methods. J. Geophys. Res. 113, B08311 (2008)

    ADS  Google Scholar 

  77. 77

    Obara, K., Hirose, H., Yamamizu, F. & Kasahara, K. Episodic slow slip events accompanied by non-volcanic tremors in southwest Japan subduction zone. Geophys. Res. Lett. 31, L23602 (2004)

    ADS  Google Scholar 

  78. 78

    Sekine, S., Hirose, H. & Obara, K. Along-strike variations in short-term slow slip events in the southwest Japan subduction zone. J. Geophys. Res. 115, B00A27 (2010)

    ADS  Google Scholar 

  79. 79

    Kao, H., Shan, S., Dragert, H. & Rogers, G. Northern Cascadia episodic tremor and slip: a decade of tremor observations from 1997 to 2007. J. Geophys. Res. 114, B00A12 (2009)

    Google Scholar 

  80. 80

    Dragert, H. & Wang, K. Temporal evolution of an ETS event along the northern Cascadia margin. J. Geophys. Res. 116, B12406 (2011)

    ADS  Google Scholar 

  81. 81

    Wech, A. G. & Creager, K. C. A continuum of stress, strength and slip in the Cascadia subduction zone. Nat. Geosci. 4, 624–628 (2011)

    ADS  CAS  Google Scholar 

  82. 82

    Fry, B., Chao, K., Bannister, S., Peng, Z. & Wallace, L. M. Deep tremor in New Zealand triggered by the 2010 Mw8.8 Chile earthquake. Geophys. Res. Lett. 38, L15306 (2011)

    ADS  Google Scholar 

  83. 83

    Ide, S. Variety and spatial heterogeneity of tectonic tremor worldwide. J. Geophys. Res. 117, B03302 (2012)

    ADS  Google Scholar 

  84. 84

    Nadeau, R. M. & Dolenc, D. Nonvolcanic tremors deep beneath the San Andreas Fault. Science 307, 389 (2005)

    CAS  PubMed  Google Scholar 

  85. 85

    Peng, Z., Vidale, J. E., Wech, A., Nadeau, R. M. & Creager, K. M. Remote triggering of tremor around the Parkfield section of the San Andreas Fault. J. Geophys. Res. 114, B00A06 (2009)

    ADS  Google Scholar 

  86. 86

    Shelly, D. R. & Hardebeck, J. L. Precise tremor source locations and amplitude variations along the lower-crustal central San Andreas Fault. Geophys. Res. Lett. 37, L14301 (2010)

    ADS  Google Scholar 

  87. 87

    Ito, Y. & Obara, K. Dynamic deformation of the accretionary prism excites very low frequency earthquakes. Geophys. Res. Lett. 33, L02311 (2006)

    ADS  Google Scholar 

  88. 88

    Bostock, M. G., Royer, A. A., Hearn, E. H. & Peacock, S. M. Low frequency earthquakes below southern Vancouver Island. Geochem. Geophys. Geosyst. 13, Q11007 (2012)

    ADS  Google Scholar 

  89. 89

    Royer, A. A. & Bostock, M. G. A comparative study of low frequency earthquake templates in northern Cascadia. Earth Planet. Sci. Lett. 402, 247–256 (2014)

    CAS  Google Scholar 

  90. 90

    Ide, S. Characteristics of slow earthquakes in the very low frequency band: application to the Cascadia subduction zone. J. Geophys. Res. 121, 1–11 (2016)

    Google Scholar 

  91. 91

    Frank, W. B. et al. Low-frequency earthquakes in the Mexican Sweet Spot. Geophys. Res. Lett. 40, 2661–2666 (2013)

    ADS  Google Scholar 

  92. 92

    Maury, J. et al. Comparative study of tectonic tremor locations: characterization of slow earthquakes in Guerrero, Mexico. J. Geophys. Res. 121, 5136–5151 (2016)

    ADS  Google Scholar 

  93. 93

    Wu, C., Shelly, D. R., Gomberg, J., Peng, Z. & Johnson, P. Long-term changes of earthquake inter-event times and low-frequency earthquake recurrence in central California. Earth Planet. Sci. Lett. 368, 144–150 (2013)

    ADS  CAS  Google Scholar 

  94. 94

    Hirose, H. et al. Slow earthquakes linked along dip in the Nankai subduction zone. Science 330, 1502 (2010)

    ADS  CAS  PubMed  Google Scholar 

  95. 95

    Ozawa, S., Yarai, H., Imakiire, T. & Tobita, M. Spatial and temporal evolution of the long-term slow slip in the Bungo Channel, Japan. Earth Planets Space 65, 67–73 (2013)

    ADS  Google Scholar 

  96. 96

    Kobayashi, A. A small scale long-term slow slip occurred in the western Shikoku in 2005. [in Japanese with English abstract] J. Seismol. Soc. Jpn 63, 97–100 (2010)

    Google Scholar 

  97. 97

    Kobayashi, A. Long-term slow slip event around Kochi City from 1977 to 1980. [in Japanese with English abstract] J. Seismol. Soc. Jpn 64, 63–73 (2012)

    ADS  Google Scholar 

  98. 98

    Kobayashi, A. A long-term slow slip event from 1996 to 1997 in the Kii Channel, Japan. Earth Planets Space 66, 9 (2014)

    ADS  Google Scholar 

  99. 99

    Takagi, R., Obara, K. & Maeda, T. Slow slip event within a gap between tremor and locked zones in the Nankai subduction zone. Geophys. Res. Lett. 43, 1066–1074 (2016)

    ADS  Google Scholar 

  100. 100

    Lowry, A. R., Larson, K. M., Kostoglodov, V. & Sanchez, O. The fault slip budget in Guerrero, southern Mexico. Geophys. J. Int. 200, 1–15 (2005)

    Google Scholar 

  101. 101

    Larson, K. M., Kostoglodov, V., Miyazaki, S. & Santiago, J. A. S. The 2006 aseismic slow slip event in Guerrero, Mexico: new results from GPS. Geophys. Res. Lett. 34, L13309 (2007)

    ADS  Google Scholar 

  102. 102

    Kostoglodov, V. et al. The 2006 slow slip event and nonvolcanic tremor in the Mexican subduction zone. Geophys. Res. Lett. 37, L24301 (2010)

    ADS  Google Scholar 

  103. 103

    Cavalié, O. et al. Slow slip event in the Mexican subduction zone: evidence of shallower slip in the Guerrero seismic gap for the 2006 event revealed by the joint inversion of InSAR and GPS data. Earth Planet. Sci. Lett. 367, 52–60 (2013)

    ADS  Google Scholar 

  104. 104

    Wallace, L. M. & Beavan, J. Diverse slow slip behavior at the Hikurangi subduction margin, New Zealand. J. Geophys. Res. 115, B12402 (2010)

    ADS  Google Scholar 

  105. 105

    Wallace, L. M. & Eberhart-Phillips, D. Newly observed, deep slow slip events at the central Hikurangi margin, New Zealand: Implications for downdip variability of slow slip and tremor, and relationship to seismic structure. Geophys. Res. Lett. 40, 5393–5398 (2013)

    ADS  Google Scholar 

  106. 106

    Kodaira, S. et al. High pore fluid pressure may cause silent slip in the Nankai Trough. Science 304, 1295–1298 (2004)

    ADS  CAS  PubMed  Google Scholar 

  107. 107

    Kato, A. et al. Variations of fluid pressure within the subducting oceanic crust and slow earthquakes. Geophys. Res. Lett. 37, L14310 (2010)

    ADS  Google Scholar 

  108. 108

    Audet, P., Bostock, M. G., Christensen, N. I. & Peacock, S. M. Seismic evidence for overpressured subducted oceanic crust and megathrust fault sealing. Nature 457, 76–78 (2009)

    ADS  CAS  PubMed  Google Scholar 

  109. 109

    Peacock, S. M., Christensen, N. I., Bostock, M. G. & Audet, P. High pore pressure and porosity at 35 km depth in the Cascadia subduction zone. Geology 39, 471–474 (2011)

    ADS  Google Scholar 

  110. 110

    Wannamaker, P. E. et al. Segmentation of plate coupling, fate of subduction fluids, and modes of arc magmatism in Cascadia, inferred from magnetotelluric resistivity. Geochem. Geophys. Geosyst. 15, 4230–4253 (2014)

    ADS  Google Scholar 

  111. 111

    Jödicke, H. et al. Fluid release from the subducted Cocos plate and partial melting of the crust deduced from magnetotelluric studies in southern Mexico: Implications for the generation of volcanism and subduction dynamics. J. Geophys. Res. 111, B08102 (2006)

    ADS  Google Scholar 

  112. 112

    Bannister, S., Reyners, M., Stuart, G. & Savage, M. Imaging the Hikurangi subduction zone, New Zealand, using teleseismic receiver functions: crustal fluids above the forearc mantle wedge. Geophys. J. Int. 169, 602–616 (2007)

    ADS  Google Scholar 

Download references


We thank J. He for developing the computer code PGCtherm2D employed in this work. X.G. was supported by the Chinese Academy of Sciences’ Strategic Priority Research Program (grant XDA11030102) and the National Natural Science Foundation of China (grant 41406063). K.W. was supported by Geological Survey of Canada core funding and Discovery Grant from Natural Sciences and Engineering Research Council of Canada through the University of Victoria. This is Geological Survey of Canada contribution 20160265.

Author information




X.G. conducted the thermal and rheological modelling. X.G. and K.W. jointly designed the research and contributed equally to the writing.

Corresponding author

Correspondence to Kelin Wang.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Additional information

Reviewer Information Nature thanks P. Audet and D. Shelly for their contribution to the peer review of this work.

Extended data figures and tables

Extended Data Figure 1 The function (see equations (4) and (5)) used to scale fault shear stresses to simulate the effect of high Pf.

The shown updip skewed (q = 0.3) and broad (b = 0.3) distribution is used for all models in this work. The distance is measured from the updip end of the high-Pf zone and normalized by its width W.

Extended Data Figure 2 Map view of the distribution of megathrust seismogenic zone, slow slip events, and tremor at the northern Cascadia, Mexico, Japan Trench, and Hikurangi subduction zones.

Data are based on references given in Extended Data Table 2. Red patches show tremor distribution (or ETS zone). Blue patches indicate slip areas of long-term SSEs (labelled with year of occurrence). Yellow shading shows megathrust earthquakes (labelled with year of occurrence) or inferred seismogenic zone. Thick blue line indicates thermal model profile. References for the depth contours (in kilometres) of the plate interface (dashed lines) are given in Extended Data Table 1. a, Northern Cascadia. The megathrust coseismic slip scenario is from ref. 8. b, Mexico. c, The Japan Trench. Green patches are rupture areas of Mw > 7.0, moderate to large interplate earthquakes51,52. Bold green line marks the downdip limit of reported interplate earthquakes of all sizes25. d, Hikurangi. The megathrust of the northern two-thirds of the margin is almost fully creeping, as inferred from GPS observations26,53.

Extended Data Table 1 Summary of subduction zones studied here
Extended Data Table 2 Fault slip phenomena in subduction zones studied here and in the SAF

PowerPoint slides

Source data

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Gao, X., Wang, K. Rheological separation of the megathrust seismogenic zone and episodic tremor and slip. Nature 543, 416–419 (2017).

Download citation

Further reading


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.


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