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.

Coseismic fault lubrication by viscous deformation


Despite the hazard posed by earthquakes, we still lack fundamental understanding of the processes that control fault lubrication behind a propagating rupture front and enhance ground acceleration. Laboratory experiments show that fault materials dramatically weaken when sheared at seismic velocities (>0.1 m s−1). Several mechanisms, triggered by shear heating, have been proposed to explain the coseismic weakening of faults, but none of these mechanisms can account for experimental and seismological evidence of weakening. Here we show that, in laboratory experiments, weakening correlates with local temperatures attained during seismic slip in simulated faults for diverse rock-forming minerals. The fault strength evolves according to a simple, material-dependent Arrhenius-type law. Microstructures support this observation by showing the development of a principal slip zone with textures typical of sub-solidus viscous flow. We show evidence that viscous deformation (at either sub- or super-solidus temperatures) is an important, widespread and quantifiable coseismic lubrication process. The operation of these highly effective fault lubrication processes means that more energy is then available for rupture propagation and the radiation of hazardous seismic waves.

This is a preview of subscription content

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Mechanical data.
Fig. 2: Microstructures.
Fig. 3: Deformation mechanisms.
Fig. 4: Mechanical data in Arrhenius space.

Data availability

The mechanical data used for Figs. 1 and 4 are archived on Zenodo at All data are available from the authors on request. Source data are provided with this paper.


  1. 1.

    Global Death Toll Due to Earthquakes from 2000 to 2015 (Statista Research Department, 2016);

  2. 2.

    Kanamori, H. & Rivera, L. in Earthquakes: Radiated Energy and the Physics of Faulting (eds Abercrombie, R. et al.) 3–13 (AGU, 2006).

  3. 3.

    Nielsen, S. et al. G: fracture energy, friction and dissipation in earthquakes. J. Seismol. 20, 1187–1205 (2016).

    Article  Google Scholar 

  4. 4.

    Di Toro, G. et al. Fault lubrication during earthquakes. Nature 471, 494–499 (2011).

    Article  Google Scholar 

  5. 5.

    Goldsby, D. L. & Tullis, T. E. Flash heating leads to low frictional strength of crustal rocks at earthquake slip rates. Science 334, 216–218 (2011).

    Article  Google Scholar 

  6. 6.

    Hirose, T. & Shimamoto, T. Growth of molten zone as a mechanism of slip weakening of simulated faults in gabbro during frictional melting. J. Geophys. Res. 110, B05202 (2005).

    Google Scholar 

  7. 7.

    Scholz, C. H. & Christopher, H. The Mechanics of Earthquakes and Faulting (Cambridge Univ. Press, 2002).

  8. 8.

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

    Article  Google Scholar 

  9. 9.

    Rice, J. R. Flash heating at asperity contacts and rate-dependent friction. Eos Trans. AGU 80, F6811 (1999).

    Google Scholar 

  10. 10.

    Di Toro, G., Hirose, T., Nielsen, S., Pennacchioni, G. & Shimamoto, T. Natural and experimental evidence of melt lubrication of faults during earthquakes. Science 311, 647–649 (2006).

    Article  Google Scholar 

  11. 11.

    Spray, J. G. Frictional melting processes in planetary materials: from hypervelocity impact to earthquakes. Annu. Rev. Earth Planet. Sci. 38, 221–254 (2010).

    Article  Google Scholar 

  12. 12.

    Hayward, K. S., Hawkins, R., Cox, S. F. & Le Losq, C. Rheological controls on asperity weakening during earthquake slip. J. Geophys. Res. Solid Earth 124, 12736–12762 (2019).

    Article  Google Scholar 

  13. 13.

    Rice, J. R. Heating and weakening of faults during earthquake slip. J. Geophys. Res. Solid Earth 111, B05311 (2006).

    Article  Google Scholar 

  14. 14.

    Viesca, R. C. & Garagash, D. I. Ubiquitous weakening of faults due to thermal pressurization. Nat. Geosci. 8, 875–879 (2015).

    Article  Google Scholar 

  15. 15.

    Reches, Z. & Lockner, D. A. Fault weakening and earthquake instability by powder lubrication. Nature 467, 452–455 (2010).

    Article  Google Scholar 

  16. 16.

    Han, R., Hirose, T. & Shimamoto, T. Strong velocity weakening and powder lubrication of simulated carbonate faults at seismic slip rates. J. Geophys. Res. Solid Earth 115, B03412 (2010).

    Google Scholar 

  17. 17.

    Di Toro, G., Goldsby, D. L. & Tullis, T. E. Friction falls towards zero in quartz rock as slip velocity approaches seismic rates. Nature 427, 436–439 (2004).

    Article  Google Scholar 

  18. 18.

    Sulem, J. & Famin, V. Thermal decomposition of carbonates in fault zones: slip-weakening and temperature-limiting effects. J. Geophys. Res. 114, B03309 (2009).

    Google Scholar 

  19. 19.

    Green, H. W., Shi, F., Bozhilov, K., Xia, G. & Reches, Z. Phase transformation and nanometric flow cause extreme weakening during fault slip. Nat. Geosci. 8, 448–489 (2015).

    Google Scholar 

  20. 20.

    De Paola, N., Holdsworth, R. E., Viti, C., Collettini, C. & Bullock, R. Can grain size sensitive flow lubricate faults during the initial stages of earthquake propagation? Earth Planet. Sci. Lett. 431, 48–58 (2015).

    Article  Google Scholar 

  21. 21.

    Pozzi, G., De Paola, N., Nielsen, S. B., Holdsworth, R. E. & Bowen, L. A new interpretation for the nature and significance of mirror-like surfaces in experimental carbonate-hosted seismic faults. Geology 46, 583–586 (2018).

    Article  Google Scholar 

  22. 22.

    Pozzi, G. et al. Coseismic ultramylonites: an investigation of nanoscale viscous flow and fault weakening during seismic slip. Earth Planet. Sci. Lett. 516, 164–175 (2019).

    Article  Google Scholar 

  23. 23.

    Nielsen, S., Di Toro, G., Hirose, T. & Shimamoto, T. Frictional melt and seismic slip. J. Geophys. Res. Solid Earth 113, B01308 (2008).

    Article  Google Scholar 

  24. 24.

    De Paola, N. et al. Fault lubrication and earthquake propagation in thermally unstable rocks. Geology 39, 35–38 (2011).

    Article  Google Scholar 

  25. 25.

    De Paola, N. et al. The geochemical signature caused by earthquake propagation in carbonate-hosted faults. Earth Planet. Sci. Lett. 310, 225–232 (2011).

    Article  Google Scholar 

  26. 26.

    De Paola, N., Faulkner, D. R. & Collettini, C. Brittle versus ductile deformation as the main control on the transport properties of low-porosity anhydrite rocks. J. Geophys. Res. 114, B06211 (2009).

    Google Scholar 

  27. 27.

    Buijze, L., Niemeijer, A. R., Han, R., Shimamoto, T. & Spiers, C. J. Friction properties and deformation mechanisms of halite(-mica) gouges from low to high sliding velocities. Earth Planet. Sci. Lett. 458, 107–119 (2017).

    Article  Google Scholar 

  28. 28.

    Thieme, M., Demouchy, S., Mainprice, D., Barou, F. & Cordier, P. Stress evolution and associated microstructure during transient creep of olivine at 1000–1200 °C. Phys. Earth Planet. Inter. 278, 34–46 (2018).

    Article  Google Scholar 

  29. 29.

    Gasc, J., Demouchy, S., Barou, F., Koizumi, S. & Cordier, P. Creep mechanisms in the lithospheric mantle inferred from deformation of iron-free forsterite aggregates at 900–1200 °C. Tectonophysics 761, 16–30 (2019).

    Article  Google Scholar 

  30. 30.

    Sibson, R. H. Fault rocks and fault mechanisms. J. Geol. Soc. Lond. 133, 191–213 (1977).

    Article  Google Scholar 

  31. 31.

    Brantut, N. & Platt, J. D. in Fault Zone Dynamic Processes: Evolution of Fault Properties During Seismic Rupture (eds Thomas, M. Y. et al.) 171–194 (AGU, 2017);

  32. 32.

    Ashby, M. F. & Verrall, R. A. Diffusion-accommodated flow and superplasticity. Acta Metall. 21, 149–163 (1973).

    Article  Google Scholar 

  33. 33.

    Dygert, N., Bernard, R. E. & Behr, W. M. Great basin mantle xenoliths record active lithospheric downwelling beneath central Nevada. Geochem. Geophys. Geosyst. 20, 751–772 (2019).

    Article  Google Scholar 

  34. 34.

    Wheeler, J. Anisotropic rheology during grain boundary diffusion creep and its relation to grain rotation, grain boundary sliding and superplasticity. Philos. Mag. 90, 2841–2864 (2010).

    Article  Google Scholar 

  35. 35.

    Miyazaki, T., Sueyoshi, K. & Hiraga, T. Olivine crystals align during diffusion creep of Earth’s upper mantle. Nature 502, 321–326 (2013).

    Article  Google Scholar 

  36. 36.

    Poirier, J.-P. Creep of Crystals. High-Temperature Deformation Processes in Metals, Ceramics and Minerals (Cambridge Univ. Press, 1985);

  37. 37.

    Barnhoorn, A., Bystricky, M., Burlini, L. & Kunze, K. The role of recrystallisation on the deformation behaviour of calcite rocks: large strain torsion experiments on Carrara marble. J. Struct. Geol. 26, 885–903 (2004).

    Article  Google Scholar 

  38. 38.

    De Bresser, J. H. P., Ter Heege, J. H. & Spiers, C. J. Grain size reduction by dynamic recrystallization: can it result in major rheological weakening? Int. J. Earth Sci. 90, 28–45 (2001).

    Article  Google Scholar 

  39. 39.

    Kohlstedt, D. L. in Treatise on Geophysics Vol. 2 (ed. Price, G. D.) 389–417 (Elsevier, 2007).

  40. 40.

    Mackwell, S. J. & Paterson, M. S. New developments in deformation studies: high-strain deformation. Rev. Mineral. Geochem. 51, 1–19 (2002).

    Article  Google Scholar 

  41. 41.

    Frost, H. J. & Ashby, M. F. Deformation-Mechanism Maps: The Plasticity and Creep of Metals and Ceramics (Pergamon Press, 1982).

  42. 42.

    Schmid, S. M., Boland, J. N. & Paterson, M. S. Superplastic flow in finegrained limestone. Tectonophysics 43, 257–291 (1977).

    Article  Google Scholar 

  43. 43.

    Pieri, M., Burlini, L., Kunze, K., Stretton, I. & Olgaard, D. L. Rheological and microstructural evolution of Carrara marble with high shear strain: results from high temperature torsion experiments. J. Struct. Geol. 23, 1393–1413 (2001).

    Article  Google Scholar 

  44. 44.

    Wang, Q. Homologous temperature of olivine: implications for creep of the upper mantle and fabric transitions in olivine. Sci. China Earth Sci. 59, 1138–1156 (2016).

    Article  Google Scholar 

  45. 45.

    Handy, M. R. The energetics of steady state heterogeneous shear in mylonitic rock. Mater. Sci. Eng. A 175, 261–272 (1994).

    Article  Google Scholar 

  46. 46.

    Philpotts, A. R., Anthony R. & Ague, J. J. Principles of Igneous and Metamorphic Petrology (Cambridge Univ. Press, 2009).

  47. 47.

    Yao, L., Ma, S., Platt, J. D., Niemeijer, A. R. & Shimamoto, T. The crucial role of temperature in high-velocity weakening of faults: experiments on gouge using host blocks with different thermal conductivities. Geology 44, 63–66 (2016).

    Article  Google Scholar 

Download references


We thank B. Mendis, L. Bowen and F. Barou for their assistance with the acquisition of SEM and TEM images and discussion, and A. Beeby for acquiring Raman spectra on our samples. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 642029 - ITN CREEP to N.D.P. and the Natural Environment Research Council (NERC) through a NERC standard grant NE/H021744/1 to N.D.P.

Author information




G.P. ran the experiments and carried out the microstructural analysis and interpretations. G.P., N.D.P., S.B.N., R.E.H. and T.T. contributed equally to the concept development and to the writing of the paper. All authors jointly supervised this work.

Corresponding authors

Correspondence to Giacomo Pozzi or Nicola De Paola.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Geoscience thanks Stephen F. Cox and the other, 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 Sections I–VI, Figs. 1–16, Tables 1 and 2, and Equations 1–7.

Source data

Source Data Fig. 1

Tabulated mechanical data.

Source Data Fig. 4

Tabulated mechanical data.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Pozzi, G., De Paola, N., Nielsen, S.B. et al. Coseismic fault lubrication by viscous deformation. Nat. Geosci. 14, 437–442 (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