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Seismic and aseismic slip on the Central Peru megathrust



Slip on a subduction megathrust can be seismic or aseismic, with the two modes of slip complementing each other in time and space to accommodate the long-term plate motions. Although slip is almost purely aseismic at depths greater than about 40 km, heterogeneous surface strain1,2,3,4,5,6,7,8 suggests that both modes of slip occur at shallower depths, with aseismic slip resulting from steady or transient creep in the interseismic and postseismic periods9,10,11. Thus, active faults seem to comprise areas that slip mostly during earthquakes, and areas that mostly slip aseismically. The size, location and frequency of earthquakes that a megathrust can generate thus depend on where and when aseismic creep is taking place, and what fraction of the long-term slip rate it accounts for. Here we address this issue by focusing on the central Peru megathrust. We show that the Pisco earthquake, with moment magnitude Mw = 8.0, ruptured two asperities within a patch that had remained locked in the interseismic period, and triggered aseismic frictional afterslip on two adjacent patches. The most prominent patch of afterslip coincides with the subducting Nazca ridge, an area also characterized by low interseismic coupling, which seems to have repeatedly acted as a barrier to seismic rupture propagation in the past. The seismogenic portion of the megathrust thus appears to be composed of interfingering rate-weakening and rate-strengthening patches. The rate-strengthening patches contribute to a high proportion of aseismic slip, and determine the extent and frequency of large interplate earthquakes. Aseismic slip accounts for as much as 50–70% of the slip budget on the seismogenic portion of the megathrust in central Peru, and the return period of earthquakes with Mw = 8.0 in the Pisco area is estimated to be 250 years.

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Figure 1: Seismotectonic setting of the South Peru megathrust.
Figure 2: Fault slip derived from modelling of geodetic displacements between days 20 and 408 after the mainshock.
Figure 3: Comparison of interseismic coupling with the rupture areas of recent large earthquakes.


  1. Savage, J. A dislocation model of strain accumulation and release at a subduction zone. J. Geophys. Res. 88, 4984–4996 (1983)

    ADS  Article  Google Scholar 

  2. Freymueller, J. & Beavan, J. Absence of strain accumulation in the Western Shumagin segment of the Alaska subduction zone. Geophys. Res. Lett. 26, 3233–3236 (1999)

    ADS  Article  Google Scholar 

  3. Mazzotti, S., Pichon, X. L., Henry, P. & Miyazaki, S. Full interseismic locking of the Nankai and Japan-West Kurile subduction zones: an analysis of uniform elastic strain accumulation in Japan constrained by permanent GPS. J. Geophys. Res. 105, 13159–13159 (2000)

    ADS  Article  Google Scholar 

  4. Burgmann, R., Kogan, M. G., Steblov, G. M., Hilley, G. & Levin, V. E. Interseismic coupling and asperity distribution along the Kamchatka subduction zone. J. Geophys. Res. 110 10.1020/2005JB003648 (2005)

  5. Chlieh, M., Avouac, J.-P., Sieh, K., Natawidjaja, D. & Galetzka, J. Heterogeneous coupling of the sumatran megathrust constrained by geodetic and paleogeodetic measurements. J. Geophys. Res. 113 10.1029/2007JB004981 (2008)

  6. Moreno, M., Klotz, J., Melnick, D., Echtler, H. & Bataille, K. Active faulting and heterogeneous deformation across a megathrust segment boundary from GPS data, South Central Chile (36°–39°s). Geochem. Geophys. Geosyst. 9 10.1029/2008GC002198 (2008)

  7. Igarashi, T., Matsuzawa, T. & Hasegawa, A. Repeating earthquakes and interplate aseismic slip in the Northeastern Japan subduction zone. J. Geophys. Res. 108 10.1029/2002JB001920 (2003)

  8. Suwa, Y., Hasegawa, A., Sato, T. & Tachibana, K. Interplate coupling beneath NE Japan inferred from three-dimensional displacement field. J. Geophys. Res. 111 10.1029/2004JB003203 (2006)

  9. Hirose, H., Hirahara, K., Kimata, F., Fujii, N. & Miyazaki, S. A slow thrust slip event following the two 1996 Hyuganada earthquakes beneath the Bungo channel, southwest Japan. Geophys. Res. Lett. 26, 3237–3240 (1999)

    ADS  Article  Google Scholar 

  10. Miyazaki, S. et al. Modeling the rupture process of the 2003 September 25 Tokachi-Oki (Hokkaido) earthquake using 1-Hz GPS data. Geophys. Res. Lett. 31 10.1029/2004GL021457 (2004)

  11. Hsu, Y.-J. et al. Frictional afterslip following the 2005 Nias-Simeulue earthquake, Sumatra. Science 312, 1921–1926 (2006)

    CAS  ADS  Article  Google Scholar 

  12. Bilek, S., Lay, T. & Ruff, L. Radiated seismic energy and earthquake source duration variations from teleseismic source time functions for shallow subduction zone thrust earthquakes. J. Geophys. Res. 109 10.1029/2004JB003039 (2004)

  13. Sladen, A. et al. Source model of the 2007 M w8.0 Pisco, Peru earthquake—implications for seismogenic behavior of subduction megathrusts. J. Geophys. Res. 115 10.1029/2009JB006429 (2010)

  14. Kendrick, E., Bevis, M., Smalley, R. & Brooks, B. An integrated crustal velocity field for the Central Andes. Geochem. Geophys. Geosyst. 2 10.1029/2001GC000191 (2001)

  15. Gagnon, K., Chadwell, C. D. & Norabuena, E. Measuring the onset of locking in the Peru-Chile trench with GPS and acoustic measurements. Nature 434, 205–208 (2005)

    CAS  ADS  Article  Google Scholar 

  16. Dorbath, L., Cisternas, A. & Dorbath, C. Quantitative assessment of great earthquakes in Peru. Bull. Seismol. Soc. Am. 80, 551–576 (1990)

    Google Scholar 

  17. Freed, A. M., Burgmann, R., Calais, E., Freymueller, J. & Hreinsdottir, S. Implications of deformation following the 2002 Denali, Alaska, earthquake for postseismic relaxation processes and lithospheric rheology. J. Geophys. Res. 111 10.1029/2005JB003894 (2006)

  18. Okada, Y. Internal deformation due to shear and tensile faults in a half-space. Bull. Seismol. Soc. Am. 82, 1018–1040 (1992)

    Google Scholar 

  19. Kositsky, A. P. & Avouac, J.-P. Inverting geodetic time series with a principal component analysis-based inversion method. J. Geophys. Res. 115 10.1029/2009JB006535 (2010)

  20. Perfettini, H. & Avouac, J.-P. Postseismic relaxation driven by brittle creep: a possible mechanism to reconcile geodetic measurements and the decay rate of aftershocks, application to the Chi-Chi earthquake, Taiwan. J. Geophys. Res. 109 10.1029/2003JB002488 (2004)

  21. Hearn, E., Burgmann, R. & Reilinger, R. Dynamics of Izmit earthquake postseismic deformation and loading of the Duzce earthquake hypocenter. Bull. Seismol. Soc. Am. 92, 172–193 (2002)

    Article  Google Scholar 

  22. Perfettini, H., Avouac, J.-P. & Ruegg, J. Geodetic displacements and aftershocks following the 2001, M w = 8.4 Peru earthquake: implications for the mechanics of the earthquake cycle along subduction zones. J. Geophys. Res. 109 10.1029/2004JB003522 (2005)

  23. Johnson, K., Burgmann, R. & Larson, K. Frictional properties on the San Andreas fault near Parkfield, California, inferred from models of afterslip following the 2004 earthquake. Bull. Seismol. Soc. Am. 96, S321–S338 (2006)

    Article  Google Scholar 

  24. Perfettini, H. & Avouac, J.-P. Modelling afterslip and aftershocks following the 1992 Landers earthquake. J. Geophys. Res. 112 10.1029/2006JB004399 (2007)

  25. Baba, T., Hirata, K., Hori, T. & Sakaguchi, H. Offshore geodetic data conductive to the estimation of the afterslip distribution following the 2003 Tokachi-Oki earthquake. Earth Planet. Sci. Lett. 241, 281–292 (2006)

    CAS  ADS  Article  Google Scholar 

  26. Benioff, H. Earthquakes and rock creep. Part I: Creep characteristics of rocks and the origin of aftershocks. Bull. Seismol. Soc. Am. 41, 31–62 (1951)

    Google Scholar 

  27. Savage, J. & Langbein, J. Postearthquake relaxation after the 2004 m6 Parkfield, California earthquake and rate-and-state friction. J. Geophys. Res. 113 10.1029/2008JB005723 (2008)

  28. Langer, C. & Spence, W. The 1974 Peru earthquake series. Bull. Seismol. Soc. Am. 85, 665–687 (1995)

    Google Scholar 

  29. Pritchard, M. E. et al. Geodetic, teleseismic, and strong motion constraints on slip from recent Southern Peru subduction zone earthquakes. J. Geophys. Res. 112 10.1029/2006JB004294 (2007)

  30. Marone, C. Laboratory-derived friction laws and their application to seismic faulting. Annu. Rev. Earth Planet. Sci. 26, 643–696 (1998)

    CAS  ADS  Article  Google Scholar 

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We thank J. Freymueller and R. Burgmann for reviews that have helped improve this manuscript. We are grateful to A. Copley for help in editing the manuscript. This study has benefited from support from the Institute de Recherche pour le Développement, the Gordon and Betty Moore Foundation through the Tectonics Observatory, and the National Science Foundation through grant EAR-0838495.

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Authors and Affiliations



H.P. edited the paper and did modelling and field work; J.-P.A. edited the paper and did modelling; H.T. handled the IGP aftershocks data; A.K. did modelling of postseismic deformation; J.-M.N. did the GPS processing; F.B. was in charge of the GPS network; M.C. did modelling of interseismic deformation; A.S. did modelling of the co-seismic deformation; L.A. did field work; D.L.F. did field work, and helped with editing the paper; P.S. helped with logistics.

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Correspondence to Hugo Perfettini.

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Perfettini, H., Avouac, JP., Tavera, H. et al. Seismic and aseismic slip on the Central Peru megathrust. Nature 465, 78–81 (2010).

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