Skip to main content

Advertisement

We’d like to understand how you use our websites in order to improve them. Register your interest.

Aftershock distribution of the 26 December 2004 Sumatra-Andaman earthquake from ocean bottom seismographic observation

Abstract

We deployed an OBS network in February–March 2005 in the rupture area of the Sumatra Andaman earthquake on 26 December 2004. We placed 17 short-term OBSs and two long-term OBSs, and recovered OBSs after observation for 19–22 days. The hypocenter distribution from 10-day data of 17 OBS revealed the detailed structure of aftershock seismicity offshore of Sumatra Island. Aftershock seismicity associated with the subducting slab starts 40 km inward from the Sunda trench axis; it ceases at 50 km depth beneath the Aceh Basin, approximately 240 km inward from the trench axis. Aftershocks in 120–170 km from the trench axis consist of a surface with a dip of 10–12° dominated by a dip-extension type mechanism. Beyond the southwestern edge of the Aceh Basin, the aftershock activity becomes higher, and dominated by dip-slip type earthquakes, with a slightly increased dipping angle of 15–20°. Three along-arc bands of shallow seismicity were identified at 70 km inward from the Sumatra trench, 110 km inward from the trench, and in the south of the Aceh Basin. These locations correspond to steep topographic slopes in the accretionary prism, suggesting the present evolutional activity of the accretionary prism offshore Sumatra Island.

References

  1. Diament, M., H. Harjono, K. Karta, C. Deplus, D. Dahrin, M. T. Zen, Jr., M. Gerard, O. Lassal, A. Martin, and J. Malod, Mentawai fault zone off Sumatra: A new key to the geodynamics of western Indonesia, Geology, 20, 259–262, 1992.

    Article  Google Scholar 

  2. Engdhal, E., R. van der Hilst, and R. Buland, Global teleseismic earthquake relocation with improved travel times and procedures for depth determination, Bull. Seismol. Soc. Am., 88, 722–743, 1998.

    Google Scholar 

  3. Hirata, K., K. Satake, Y. Tanioka, T. Kuragano, Y. Hasegawa, Y Hayashi, and N. Hamada, The 2004 Indian Ocean Tsunami: Tsunami Source Model from Satellite Altimetry, Proceedings of 22nd International Tsunami Symposium, Chania, Crete Isl., Greece, 27–29 June, 2005.

    Google Scholar 

  4. Hirata, N. and M. Matsu’ura, Phys. Earth Planet. Inter., 47, 50–61, 1987.

    Article  Google Scholar 

  5. Ji, C, Preliminary Result of the 04/12/26 (Mw 9.0), Off W. Coast of Northern Sumatra Earthquake, 2005. http://www.gps.caltech.edu/_jichen/Earthquake/2004/aceh/aceh.html

    Google Scholar 

  6. Kennett, B. L. N. and E. R. Engdahl, Traveltimes for global earthquake location and phase identification, Geophys. J. Int., 105, 429–465, 1991.

    Article  Google Scholar 

  7. Kopp, H., E. R. Flueh, D. Klaeschen, J. Bialas, and C. Reichert, Crustal structure of the central Sunda margin at the onset of oblique subduction, Geophys. J. Int., 147, 449–474, 2001.

    Article  Google Scholar 

  8. Stein, S. and E. Okal, Speed and size of the Sumatra Earthquake, Nature, 434, 581–2, 2005.

    Article  Google Scholar 

  9. Tsumura, K., Determination of earthquake magnitude from duration of oscillation, Jishin, 2, 20, 1, 30–40, 1967 (in Japanese).

    Google Scholar 

  10. Wessel, P. and W. H. F. Smith, New, improved version of Generic Mapping Tools released, EOS Trans. Amer. Geophys. U., 79(47), 579, 1998.

    Article  Google Scholar 

  11. Yagi, Y, Preliminary Results of Rupture Process for 2004 Off Coast of Northern Sumatra Giant Earthquake (ver. 1), http://iisee.kenken.go.jp/staff/yagi/eq/Sumatra2004/Sumatra2004.html, 2005.

    Google Scholar 

  12. Yamanaka, Y, 04/12/26 Off W. Coast of N. Sumatra (revised), EIC Seismological Note: No. 161+, http://www.eri.u-tokyo.ac.jp/sanchu/Seismo_Note/2004/EIC161ea.html, 2005.

    Google Scholar 

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to Eiichiro Araki.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Araki, E., Shinohara, M., Obana, K. et al. Aftershock distribution of the 26 December 2004 Sumatra-Andaman earthquake from ocean bottom seismographic observation. Earth Planet Sp 58, 113–119 (2006). https://doi.org/10.1186/BF03353367

Download citation

Key words

  • Sumatra
  • Andaman
  • aftershock
  • seismicity
  • ocean bottom seismograph (OBS)
  • accretionary prism
  • plate boundary