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Global co-seismic displacements caused by the 2004 Sumatra-Andaman earthquake (Mw 9.1)


This paper presents and discusses the global co-seismic displacements caused by the 2004 Sumatra-Andaman earthquake, using quasi-static dislocation theory for a spherically symmetric earth model (Sun et al., 1996). Theoretical calculations are performed with a heterogeneous slip distribution fault model based on Ammon et al. (2005). Results show that the co-seismic horizontal displacements are large to the north-east and southwest of the fault plane. Even as far as 6000 km from the epicenter, more than 1 millimeter co-seismic horizontal displacements raised from the earthquake. This paper has three contributions: to validate the fault model (Ammon et al., 2005) by geodetic data; to interpret the displacements observed by GPS; and to provide a reference for other researchers or for other geodetic applications. Overall, the modelled and observed displacements basically agree with each other in both the near field and far field. The calculated displacements are a generally smaller than the observed ones, since considerable moment is released by slow-slips and/or aftershocks which has not been included in the fault model.


  1. Ammon, C. J., J. Chen, H. Thio et al., Rupture process of the 2004 Sumatra-Andaman earthquake, Science, 308, 1133–1139, 2005.

  2. Banerjee, P., F. F. Pollitz, and R. Burgmann, The size and duration of the Sumatra-Andaman earthquake from far-field static offsets, Science, 308, 1769–1772, 2005.

  3. Fu, G. and W. Sun, Effects of spatial distribution of fault slip on calculating co-seismic displacement: case studies of the Chi-Chi earthquake (Mw7.6) and the Kunlun earthquake (Mw 7.8), Geophys. Res. Lett., 31, L21601, doi:10.1029/2004GL020841, 2004.

  4. Khan, S. A. and O. Gudmundsson, GPS analyses of the Sumatra-Andaman earthquake, EOS Transaction American Geophysical Union, 86(9), 2005.

  5. Okada, Y, Surface deformation due to shear and tensile faults in a half-space, Bull. Seismol. Soc. Am., 75(4), 1135–1154, 1985.

  6. Okubo, M., Y. Asai, H. Ishii et al., Thousand kilometres breaking of the 2004 Sumatra earthquake proved by dynamic strain analysis, (, 2005.

  7. Okubo, S., Gravity and potential changes due to shear and tensile faults in half-space, J. Geophys. Res., 97(B5), 7137–7144, 1992.

  8. Sun, W. and S. Okubo, Effects of the earth’s spherical curvature and radial heterogeneity in dislocation studies for a point dislocation, Geophys. Res. Lett., 29(12), 1605, doi:10.1029/2001GL014497, 2002.

  9. Sun, W., S. Okubo, and P. Vanicek, Global displacement caused by dislocations in a realistic earth model, J. Geophys. Res., 101, 8561–8577, 1996.

  10. Vigny, C., W. J. F Simons, S. Abu et al., Insight into the 2004 Sumatra-Andaman earthquake from GPS measurements in Southeast Asia, Nature, 436, 201–206, 2005.

  11. Yamanaka, Y, 04/12/26 Off west coast of northern Sumatra, Earthquake information centre seismological note No. 161, Earthquake Res. Instit., Univ. Tokyo. (, 2004.

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Correspondence to Guangyu Fu.

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Fu, G., Sun, W. Global co-seismic displacements caused by the 2004 Sumatra-Andaman earthquake (Mw 9.1). Earth Planet Sp 58, 149–152 (2006).

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Key words

  • The 2004 Sumatra-Andaman earthquake
  • co-seismic displacement
  • dislocation theory