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Particle size and energetics of gouge from earthquake rupture zones


Grain size reduction and gouge formation are found to be ubiquitous in brittle faults at all scales1,2,3,4, and most slip along mature faults is observed to have been localized within gouge zones5,6. This fine-grain gouge is thought to control earthquake instability3,6,7,8, and thus understanding its properties is central to an understanding of the earthquake process7,9. Here we show that gouge from the San Andreas fault, California, with 160 km slip, and the rupture zone of a recent earthquake in a South African mine with only 0.4 m slip, display similar characteristics, in that ultrafine grains approach the nanometre scale, gouge surface areas approach 80 m2 g-1, and grain size distribution is non-fractal. These observations challenge the common perception that gouge texture is fractal10,11 and that gouge surface energy is a negligible contributor to the earthquake energy budget3,9,12. We propose that the observed fine-grain gouge is not related to quasi-static cumulative slip, but is instead formed by dynamic rock pulverization during the propagation of a single earthquake.

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Figure 1: Field setting of the investigated faults.
Figure 2: Particle size distribution (PSD) of two representative gouge samples measured for extended periods in a laser PSD analyser (see Methods).
Figure 3: Time drift for four gouge samples measured for 72–190 h.
Figure 4: Scanning electron microscope images of untreated gouge from San Andreas gouge, with an order-of-magnitude resolution increase from left to right.


  1. Sammis, C. G., Osborne, R. H., Anderson, J. L., Banerdt, M. & White, P. Self-similar cataclasis in the formation of fault gouge. Pure Appl. Geophys. 124, 53–78 (1986)

    ADS  Google Scholar 

  2. Marone, C. & Scholz, C. Particle-size distribution and microstructures within simulated fault gouge. J. Struct. Geol. 11, 799–814 (1989)

    ADS  Google Scholar 

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

    Google Scholar 

  4. Dor, O., Reches, Z. & van Aswagen, G. in Rockburst and Seismicity in Mines Vol. 5 (eds van Aswegen, G., Durrheim, R. J. & Ortlepp, W. D.) 109–112 (South African Inst. of Mining and Metallurgy, Johannesburg, 2001)

    Google Scholar 

  5. Chester, F. M., Evans, J. P. & Biegel, R. L. Internal structure and weakening mechanisms of the San-Andreas Fault. J. Geophys. Res. Solid Earth 98, 771–786 (1993)

    Google Scholar 

  6. Zoback, M. D., Hickman, S. & Ellsworth, W. San Andreas Fault observatory at depth. (2002).

  7. Ben-Zion, Y. & Sammis, C. G. Characterization of fault zones. Pure Appl. Geophys. 160, 677–715 (2003)

    ADS  Google Scholar 

  8. Sleep, N. H. & Blanpied, M. L. Creep, compaction, and the weak rheology of major faults. Nature 359, 687–692 (1992)

    ADS  Google Scholar 

  9. Olgaard, D. & Brace, W. The microstructure of gouge from a mining-induced seismic shear zone. Int. J. Rock Mech. Mining Sci. 20, 11–19 (1983)

    Google Scholar 

  10. Steacy, S. J. & Sammis, C. G. An automaton for fractal patterns of fragmentation. Nature 353, 250–252 (1991)

    ADS  Google Scholar 

  11. An, L. J. & Sammis, C. G. Particle-size distribution of cataclastic fault materials from southern California—a 3-d study. Pure Appl. Geophys. 143, 203–227 (1994)

    ADS  Google Scholar 

  12. Kanamori, H. Mechanics of earthquakes. Annu. Rev. Earth Planet. Sci. 22, 207–237 (1994)

    ADS  Google Scholar 

  13. Brune, J. N. Fault-normal dynamic unloading and loading: an explanation for ‘nongouge’ rock powder and lack of fault-parallel shear bands along the San Andreas Fault. Eos 8, 47 (2001)

    Google Scholar 

  14. Xu, R. Particle Characterization: Light Scattering Methods (Kluwer Academic, Dordrecht, 2000)

    Google Scholar 

  15. Gregg, S. J. & Sing, K. S. W. Adsorption, Surface Area and Porosity (Academic, London, 1982)

    Google Scholar 

  16. Dewers, T. A., Wilson, B. & Reches, Z. Scaling particle size in fault gouge: Variable fractal dimension or non-fractal distribution? Eos 84, NG12C-06 (2003)

    Google Scholar 

  17. Franco, F., Perez-Maqueda, L. A. & Perez-Rodriguez, J. L. The effect of ultrasound on the particle size and structural disorder of a well-ordered kaolinite. J. Colloid Interface Sci. 274, 107–117 (2004)

    ADS  CAS  PubMed  Google Scholar 

  18. Evans, J. P. & Chester, F. M. Fluid–rock interaction in faults of the San-Andreas System—Inferences from San-Gabriel fault rock geochemistry and microstructures. J. Geophys. Res. 100, 13007–13020 (1995)

    ADS  CAS  Google Scholar 

  19. Wilson, B. Meso- and Micro-structural Analysis of the San Andreas Fault at Tejon Pass, California. Thesis, Univ. Oklahoma, Norman (2004)

    Google Scholar 

  20. Smith, B. & Dandwell, D. Coulomb stress accumulation along the San Andreas Fault system. J. Geophys. Res. 108, 2296 (2003)

    ADS  Google Scholar 

  21. McGarr, A., Spottiswoode, S. M., Gay, N. C. & Ortlepp, W. D. Observations relevant to seismic driving stress, stress drop, and efficiency. J. Geophys. Res. 84, 2251–2261 (1978)

    ADS  Google Scholar 

  22. Ogasawara, H., Yanagidani, Y. & Ando, M. (eds) Seismogenic Process Monitoring (Balkema, Rotterdam, 2002)

  23. Ortlepp, W. D. Rock Fracture and Rockbursts (South Africa Institute of Mining and Metallurgy, Monograph series M9, 1997)

    Google Scholar 

  24. Hochella, M. F. Jr & Banfield, J. F. in Chemical Weathering Rates of Silicate Minerals (eds White, A. F. & Brantley, S. L.) 353–406 (Mineralogical Society of America, Washington DC, 1995)

    Google Scholar 

  25. Poliakov, A. N. B., Dmowska, R. & Rice, J. R. Dynamic shear rupture interactions with fault bends and off-axis secondary faulting. J. Geophys. Res. 107, 2295 (2002)

    ADS  Google Scholar 

  26. Li, V. C. in Fracture Mechanics of Rocks (ed. Atkinson, B. K.) 351–428 (Academic, London, 1987)

    Google Scholar 

  27. Yund, R. A., Blanpied, M. L., Tullis, T. E. & Weeks, J. D. Amorphous material in high strain experimental fault gouges. J. Geophys. Res. 95, 15589–15602 (1990)

    ADS  Google Scholar 

  28. Reches, Z. & Dewers, T. A. Gouge formation by dynamic pulverization during earthquakes. Earth Planet. Sci. Lett. (submitted)

  29. Grady, D. E. & Kipp, D. E. Geometric statistics and dynamic fragmentation. J. Appl. Phys. 58, 1210–1222 (1985)

    ADS  Google Scholar 

  30. Reches, Z. Mechanisms of slip nucleation during earthquakes. Earth Planet. Sci. Lett. 170, 475–486 (1999)

    ADS  CAS  Google Scholar 

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We thank the US National Science Foundation and the Southern California Earthquake Center for supporting this research.Authors' contributions All authors contributed equally to this work.

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Correspondence to Ze'ev Reches.

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Wilson, B., Dewers, T., Reches, Z. et al. Particle size and energetics of gouge from earthquake rupture zones. Nature 434, 749–752 (2005).

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