Skip to main content

Multi-planar structures in the aftershock distribution of the Mid Niigata prefecture Earthquake in 2004


A shallow destructive inland earthquake of M6.8 occurred on Oct. 23, 2004 (JST) in the middle part of Niigata prefecture, Japan. The aftershock activity was high as compared to those of the other shallow inland earthquakes in Japan. We relocated the sources of the main shock and aftershock activity by adopting the double-difference earthquake location algorithm. The precisely relocated hypocenter distribution shows that there are a doubleplanar structure with a distance 5 km in parallel dipping in WNW with about 50 degrees and a single-planar structure dipping in ESE with about 15 degrees. The upper and lower planes of the double plane began to be formed with the main shock and the largest aftershock of M6.5, respectively, while the ESE dipping plane began to be formed with the 3rd largest aftershock of M6.1. The three planes represent the fault planes of the large events mentioned above. The aftershock distribution is found to be a superposition of the fault planes of the main shock and the large aftershocks. The high aftershock activity is attributed to the formation of the fault planes.


  1. Disaster Prevention Research Institute of Kyoto University and Institute of Seismology and Volcanology of Kyushu University, The fault planes estimated from the aftershock distribution,, Abstract of the 161st meeting of CCEP, 2004 (in Japanese).

    Google Scholar 

  2. Meteorological Research Institute, Source process of the main shock and largest aftershock of 2004 Niigata, Chuetsu earthquake,, Abstract of the 160th meeting of CCEP, 2004 (in Japanese).

    Google Scholar 

  3. Nakamura, K., S. Aoki, and Y. Yoshida, Centroid moment tensor analysis by using the JMA broadband seismic observation network, Q. J. Seismol., 66, 1–15, 2003 (in Japanese with English abstract).

    Google Scholar 

  4. Nakamura, M. and E. Mochizuki, Focal mechanism solutions and their reliability determined p-wave first motions, Q. J. Seismol., 52, 1–14, 1988 (in Japanese with English abstract).

    Google Scholar 

  5. Okamura, Y., The geological high strain rate zone after the Neogene, in Active Faults and Seismo-Tectonics of the Eastern Margin of the Japan Sea, edited by M. Ohtake, A. Taira, and Y. Ota, pp. 111–121, University of Tokyo Press, 2002 (in Japanese).

    Google Scholar 

  6. Sagiya, T., S. Miyazaki, and T. Tada, Continuous GPS array and presentday crustal deformation of Japan, PAGEOPH, 157, 2303–2322, 2000.

    Google Scholar 

  7. Sakai, S., N. Hirata, A. Kato, E. Kurashimo, T. Iwasaki, and T. Kanazawa, Multi-fault system of the 2004 Mid-Niigata Prefecture Earthquake and its aftershocks, Earth Planets Space, 57, this issue, 417–422, 2005.

    Article  Google Scholar 

  8. Ueno, H., S. Hatakeyama, T. Aketagawa, J. Funasaki, and N. Hamada, Improvement of hypocenter determination procedure in the Japan Meteorological Agency, Q. J. Seismol., 65, 123–134, 2002 (in Japanese with English abstract).

    Google Scholar 

  9. Utsu, T., Statistical features of seismicity, in International Handbook of Earthquake and Engineering Seismology, Part A, edited by W. H. K. Lee, H. Kanamori, P. C. Jennings, and C. Kisslinger, pp. 719–732, Academic Press, 2002.

    Google Scholar 

  10. Waldhauser, F., HypoDD - A program to compute double-difference hypocenter locations, U.S.G.S. Open File Report, 01-113, 25 pp., 2001.

    Google Scholar 

  11. Waldhauser, F. and W. L. Ellsworth, A double-difference earthquake location algorithm: Method and application to the Northern Hayward fault, California, Bull. Seismol. Soc. Am., 90, 1353–1368, 2000.

    Article  Google Scholar 

  12. Wessel, P. and W. H. F. Smith, Free software helps map and display data, EOS Trans. Am. Geophys. Union, 72, 445–446, 1991.

    Article  Google Scholar 

  13. Yamanaka, Y., The earthquakes occurred in the mid Niigata prefecture on Oct., 2004,, EIC Seismological Note, 154+, 2004 (in Japanese).

    Google Scholar 

  14. Yokoyama, H., A program for seismic data analysis using the X window system, Q. J. Seismol., 60, 37–51, 1997 (in Japanese).

    Google Scholar 

Download references

Author information



Corresponding author

Correspondence to Shigeki Aoki.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Aoki, S., Nishi, M., Nakamura, K. et al. Multi-planar structures in the aftershock distribution of the Mid Niigata prefecture Earthquake in 2004. Earth Planet Sp 57, 411–416 (2005).

Download citation

Key words

  • The Mid Niigata prefecture Earthquake in 2004
  • aftershock distribution
  • double-planed seismic zone
  • fault plane
  • double-difference earthquake location algorithm