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.

  • Letter
  • Published:

Shallow fault-zone dilatancy recovery after the 2003 Bam earthquake in Iran

Nature volume 458, pages 64–68 (2009)Cite this article

Abstract

Earthquakes radiate from slip on discrete faults, but also commonly involve distributed deformation within a broader fault zone, especially near the surface. Variations in rock strain during an earthquake are caused by heterogeneity in the elastic stress before the earthquake, by variable material properties and geometry of the fault zones, and by dynamic processes during the rupture1,2. Stress changes due to the earthquake slip, both dynamic and static, have long been thought to cause dilatancy in the fault zone that recovers after the earthquake3,4,5. Decreases in the velocity of seismic waves passing through the fault zone due to coseismic dilatancy have been observed6 followed by postseismic seismic velocity increases during healing5,7,8. Dilatancy and its recovery have not previously been observed geodetically. Here we use interferometric analysis of synthetic aperture radar images to measure postseismic surface deformation after the 2003 Bam, Iran, earthquake and show reversal of coseismic dilatancy in the shallow fault zone that causes subsidence of the surface. This compaction of the fault zone is directly above the patch of greatest coseismic slip at depth. The dilatancy and compaction probably reflects distributed shear and damage to the material during the earthquake that heals afterwards. Coseismic and postseismic deformation spread through a fault zone volume may resolve the paradox of shallow slip deficits for some strike-slip fault ruptures9.

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

Figure 1: Postseismic surface deformation after the Bam, Iran, earthquake.
Figure 2: Postseismic deformation of features as function of time.
Figure 3: Transformed components of total displacement from tracks 120 and 156.
Figure 4: Shallow fault zone contraction and main fault afterslip combined model results.

Similar content being viewed by others

References

  1. Mai, P. M. & Beroza, G. C. A spatial random field model to characterize complexity in earthquake slip. J. Geophys. Res. 107 2308 10.1029/2001JB000588 (2002)

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  3. Nur, A. Effects of stress on velocity anisotropy in rocks with cracks. J. Geophys. Res. 76, 2022–2034 (1971)

    Article  ADS  Google Scholar 

  4. Scholz, C. H. Post-earthquake dilatancy recovery. Geology 2, 551–554 (1974)

    Article  ADS  Google Scholar 

  5. Vidale, J. E. & Li, Y.-G. Damage to the shallow Landers fault from the nearby Hector Mine earthquake. Nature 421, 524–526 (2003)

    Article  ADS  CAS  Google Scholar 

  6. Li, Y.-G., Chen, P., Cochran, E. S., Vidale, J. E. & Burdette, T. Seismic evidence for rock damage and healing on the San Andreas Fault associated with the 2004 M 6.0 Parkfield earthquake. Bull. Seismol. Soc. Am. 96, S349–S363 (2006)

    Article  Google Scholar 

  7. Schaff, D. P. & Beroza, G. C. Coseismic and postseismic velocity changes measured by repeating earthquakes. J. Geophys. Res. 109 B10302 10.1029/2004JB003011 (2004)

    Article  ADS  Google Scholar 

  8. Peng, Z. G. & Ben-Zion, Y. Temporal changes of shallow seismic velocity around the Karadere-Düzce branch of the North Anatolian Fault and strong ground motion. Pure Appl. Geophys. 163, 567–600 (2006)

    Article  ADS  Google Scholar 

  9. Fialko, Y., Sandwell, D., Simons, M. & Rosen, P. A. Three-dimensional deformation caused by the Bam, Iran, earthquake and the origin of shallow slip deficit. Nature 435, 295–299 (2005)

    Article  ADS  CAS  Google Scholar 

  10. Bürgmann, R. & Dresen, G. Rheology of the lower crust and upper mantle: Evidence from rock mechanics, geodesy and field observations. Annu. Rev. Earth Planet. Sci. 36, 531–567 (2008)

    Article  ADS  Google Scholar 

  11. Jónsson, S., Segall, P., Pedersen, R. & Bjornsson, G. Post-earthquake ground movements correlated to pore-pressure transients. Nature 424, 179–183 (2003)

    Article  ADS  Google Scholar 

  12. Peltzer, G., Rosen, P., Rogez, F. & Hudnut, K. Postseismic rebound in fault step-overs caused by pore fluid-flow. Science 273, 1202–1204 (1996)

    Article  ADS  CAS  Google Scholar 

  13. Johanson, I. A., Fielding, E. J., Rolandone, F. & Burgmann, R. Coseismic and postseismic slip of the 2004 Parkfield earthquake from geodetic data. Bull. Seismol. Soc. Am. 96, S269–S282 (2006)

    Article  Google Scholar 

  14. Langbein, J., Murray, J. R. & Snyder, H. A. Coseismic and initial postseismic deformation from the 2004 Parkfield, California, earthquake, observed by global positioning system, electronic distance meter, creepmeters, and borehole strainmeters. Bull. Seismol. Soc. Am. 96, S304–S320 (2006)

    Article  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  16. Talebian, M. et al. The 2003 Bam (Iran) earthquake: Rupture of a blind fault. Geophys. Res. Lett. 31 L11611 10.1029/2004GL020058 (2004)

    Article  ADS  Google Scholar 

  17. Funning, G. J., Parsons, B. E., Wright, T. J., Jackson, J. A. & Fielding, E. J. Surface displacements and source parameters of the 2003 Bam (Iran) earthquake from Envisat advanced synthetic aperture radar imagery. J. Geophys. Res. 110 B09406 10.1029/2004JB003338 (2005)

    Article  ADS  Google Scholar 

  18. Fielding, E. J. et al. Surface ruptures and building damage of the 2003 Bam, Iran, earthquake mapped by satellite synthetic aperture radar interferometric correlation. J. Geophys. Res. 110 B03302 10.1029/2004JB003299 (2005)

    Article  ADS  Google Scholar 

  19. Jackson, J. A. et al. Seismotectonic, rupture-process, and earthquake-hazard aspects of the 26 December 2003 Bam, Iran, earthquake. Geophys. J. Int. 166, 1270–1292 (2006)

    Article  ADS  Google Scholar 

  20. Motagh, M. et al. Combination of precise leveling and InSAR data to constrain source parameters of the Mw = 6.5, 26 December 2003 Bam earthquake. Pure Appl. Geophys. 163, 1–18 (2006)

    Article  ADS  Google Scholar 

  21. Peyret, M. et al. The source motion of 2003 Bam (Iran) earthquake constrained by satellite and ground-based geodetic data. Geophys. J. Int. 169, 849–865 (2007)

    Article  ADS  Google Scholar 

  22. Bürgmann, R., Rosen, P. A. & Fielding, E. J. Synthetic aperture radar interferometry to measure Earth's surface topography and its deformation. Annu. Rev. Earth Planet. Sci. 28, 169–209 (2000)

    Article  ADS  Google Scholar 

  23. Sadeghi, H., Aghda, S. M. F., Suzuki, S. & Nakamura, T. 3-D velocity structure of the 2003 Bam earthquake area (SE Iran): Existence of a low-Poisson's ratio layer and its relation to heavy damage. Tectonophysics 417, 269–283 (2006)

    Article  ADS  Google Scholar 

  24. Peltzer, G., Rosen, P., Rogez, F. & Hudnut, K. Poroelastic rebound along the Landers 1992 earthquake surface rupture. J. Geophys. Res. 103, 30131–30145 (1998)

    Article  ADS  Google Scholar 

  25. Hamiel, Y., Lyakhovsky, V. & Agnon, A. Coupled evolution of damage and porosity in poroelastic media: Theory and applications to deformation of porous rocks. Geophys. J. Int. 156, 701–713 (2004)

    Article  ADS  Google Scholar 

  26. Rosen, P. A., Hensley, S., Peltzer, G. & Simons, M. Updated repeat orbit interferometry package released. Eos 85, 47 (2004)

    Article  ADS  Google Scholar 

  27. Chen, C. W. & Zebker, H. A. Network approaches to two-dimensional phase unwrapping: Intractability and two new algorithms. J. Opt. Soc. Am. A 17, 401–414 (2000)

    Article  ADS  CAS  Google Scholar 

  28. Berardino, P., Fornaro, G., Lanari, R. & Sansosti, E. A new algorithm for surface deformation monitoring based on small baseline differential SAR interferograms. IEEE Trans. Geosci. Rem. Sens. 40, 2375–2383 (2002)

    Article  ADS  Google Scholar 

  29. Lohman, R. B. & Simons, M. Some thoughts on the use of InSAR data to constrain models of surface deformation: Noise structure and data downsampling. Geochem. Geophys. Geosyst. 6 Q01007 10.1029/2004GC000841 (2005)

    Article  ADS  Google Scholar 

  30. Thomas, A. L. Poly3D: A Three-Dimensional, Polygonal Element, Displacement Discontinuity Boundary Element Computer Program with Applications to Fractures, Faults, and Cavities in the Earth's Crust. M.Sc. Thesis, Stanford Univ. (1993)

    Google Scholar 

Download references

Acknowledgements

Envisat data are copyright 2004–07 European Space Agency and were provided under AOE project 668. We thank R. Lohman for the use of data resampling programs and discussions. We thank J. Jackson, M. Talebian, D. McKenzie, J.-P. Avouac, Z. Liu, Z.H. Li, E. Cochran, F. Horowitz, G. Peltzer, Y. Ben-Zion and E. Hearn for discussions. Part of this research was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Author Contributions E.J.F. performed the data analysis, interpretation and modelling. P.R.L. wrote the time series analysis and modelling framework programs, and contributed to interpretation. R.B. and G.J.F. contributed to modelling and interpretation. E.J.F. and R.B. wrote the manuscript with contributions from all authors.

Author information

Authors and Affiliations

  1. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA ,

    Eric J. Fielding & Paul R. Lundgren

  2. Department of Earth and Planetary Science, University of California, Berkeley, California 94720, USA,

    Roland Bürgmann

  3. Department of Earth Sciences, University of California, Riverside, California 92521, USA,

    Gareth J. Funning

Authors
  1. Eric J. Fielding
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Paul R. Lundgren
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Roland Bürgmann
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Gareth J. Funning
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Eric J. Fielding.

Supplementary information

Supplementary Information

This file contains Supplementary Notes, Supplementary Figures S1-S9 with Legends, Supplementary Tables S1-S5 and Supplementary References (PDF 3119 kb)

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

Fielding, E., Lundgren, P., Bürgmann, R. et al. Shallow fault-zone dilatancy recovery after the 2003 Bam earthquake in Iran. Nature 458, 64–68 (2009). https://doi.org/10.1038/nature07817

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature07817

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