Skip to main content


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

High resolution 3-D velocity structure in the source region of the 2000 Western Tottori Earthquake in southwestern Honshu, Japan using very dense aftershock observations


We carried out high density aftershock observations a week after the 2000 Western Tottori Earthquake for 40 days. We deployed 72 seismic stations in and around the aftershock area. The average spacing of the stations in the aftershock area was 4–5 km. We determined accurate hypocenters and focal mechanisms for 1,000 aftershocks and obtained a high resolution 3-D velocity structure in the source region. High P and S wave velocity anomalies (> 4%) near the southeasternmost aftershock area at 2 km depth correlated with Jurassic to Late Cretaceous plutonic and high pressure metamorphic rocks. The depth distribution of the P and S wave velocities along the mainshock fault showed that high velocity anomalies were located at the shallow southeastern edge and the deeper central part of the aftershock area. The ratio between P and S wave velocities in the high velocity anomalies was a little higher (1.75) than the average value (1.70) in the upper crust. These results indicate that the high velocity anomalies could correspond to the plutonic or metamorphic rocks. The distributions of the high velocity anomalies and large slips of the mainshock were complementary. These suggest that the high velocity anomalies could be stronger than the surrounding materials and might behave as barriers to the mainshock rupture.


  1. Eberhart-Phillips, D., Three-dimensional P and S velocity structure in the Coalinga Region, California, J. Geophys. Res., 95, 15343–15363, 1990.

  2. Eberhart-Phillips, D. and A. J. Michael, Three-dimensional velocity structure, seismicity, and fault structure in the Parkfield region, central California, J. Geophys. Res., 98, 15737–15758, 1993.

  3. Eberhart-Phillips, D., V. F. Labson, W. D. Stanley, A. J. Michael, and B. D. Rodriguez, Preliminary velocity and resistivity models of the Loma Prieta earthquake region, Geophys. Res. Lett., 17, 1235–1238, 1990.

  4. Fukuyama, E., M. Ishida, S. Horiuchi, H. Inoue, S. Hori, S. Sekiguchi, T. Eguchi, A. Kubo, H. Kawai, H. Murakami, S. Yamamoto, and K. Nonomura, NIED Seismic Moment Tensor Catalogue January-December, 2000, Technical Note of the National Research Institute for Earth Science and Disaster Prevention, 217, 1–131, 2001.

  5. Fukuyama, E., W. L. Ellsworth, F. Waldhauser, and A. Kubo, Detailed fault structure of the 2000Western Tottori, Japan, Earthquake sequence, Bull. Seism. Soc. Am., 93, 1468–1478, 2003.

  6. Hirahara, K., N. Hirata, A. Ikami, H. Miyamachi, T. Yabuki, H. Aoki, I. Fujii, T. Haneda, A. Hasegawa, S. Hashimoto, N. Hirano, S. Horiuchi, Y. Iio, Y. Ishiketa, A. Ito, K. Ito, T. Kanazawa, S. Kaneshima, I. Karakama, M. Kobayashi, M. Koizumi, T. Kono, M. Kosuga, Y. Kurata, S. Kuriyama, A. Kuroiso, T. Matsuzawa, T. Mikumo, T. Mitsunami, K. Miura, Kazuaki Miura, R. Miyajima, M. Mizoue, T. Moriya, A. Nakajima, I. Nakamura, M. Nakamura, T. Nakamura, K. Nishigami, K. Oike, T. Okamoto, T. Okura, T. Ooida, T. Ouchi, T. Saeki, K. Sakai, T. Shibutani, M. Suzuki, S. Suzuki, M. Takahashi, A. Takagi, F. Takeuchi, T. Tanada, S. Tomita, T. Tsukuda, Y. Umeda, H. Wada, M. Yamada, A. Yamamoto, K. Yamashina, F. Yamazaki, and M. Yokohama, Threedimensional P and S wave velocity structure in the focal region of the 1984 Western Nagano Prefecture Earthquake, J. Phys. Earth, 40, 343–360, 1992.

  7. Hirata, N. and M. Matsu’ura, Maximum-likelihood estimation of hypocenter with origin time eliminated using nonlinear inversion technique, Phys. Earth Planet. Inter., 47, 50–61, 1987.

  8. Iizumi, S. and Research Group for the Batholith in the San’in Zone, The Neu Granitic Pluton—Petrographical study on the batholith in the San’in Zone, Southwest Japan (Part 1)—, J. Geol. Soc. Jpn., 88, 299–310, 1982 (in Japanese with English abstract).

  9. Iwata, T. and H. Sekiguchi, Source inversion of recent earthquakes using strong motion records, in a special issue on Strong Motion Prediction, Chikyu Monthly, 37, 47–55, 2002 (in Japanese).

  10. Katao, H., N. Maeda, Y. Hiramatsu, Y. Iio, and S. Nakao, Detailed Mapping of Focal Mechanisms in/around the 1995 Hyogo-ken Nanbu Earthquake Rupture Zone, J. Phys. Earth, 45, 105–119, 1997.

  11. Kissling, E., W. L. Ellsworth, D. Eberhart-Phillips, and U. Kradolfer, Initial reference models in local earthquake tomography, J. Geophys. Res., 99, 19635–19646, 1994.

  12. Maeda, N., A method of determining focal mechanisms and quantifying the uncertainty of the determined focal mechanisms for microearthquakes, Bull. Seism. Soc. Am., 82, 2410–2429, 1992.

  13. Mikumo, T., K. Hirahara, and T. Miyatake, Dynamical fault rupture processes in heterogeneous media, Techtonophysics, 144, 19–36, 1987.

  14. Ohmi, S., K. Watanabe, T. Shibutani, S. Nakao, N. Hirano, A. Nakao, H. Takeuchi, F. Takeuchi, S. Miwa, A. Shito, A. Kim, and B. Enescu, The 2000 Tottori-ken Seibu Earthquake—Seismic activity derived from the compilation of DPRI, JMA and Hi-net data—, Annu. Disas. Prev. Res. Inst., Kyoto Univ., 44B-1, 273–282, 2001 (in Japanese with English abst

  15. Ohmi, S., K. Watanabe, T. Shibutani, N. Hirano and S. Nakao, The 2000 Western Tottori Earthquake—Seismic activity revealed by the regional seismic networks—, Earth Planets Space, 54, 819–830, 2002.

  16. Oike, K., On a list of hypocenters compiled by the Tottori Microearthquake Observatory, Zisin (J. Seismol. Soc. Jpn.), 28, 331–346, 1975 (in Japanese with English abstract).

  17. Oshiman, N. and Research Group for Crustal Resistivity Structure 2001, Deep crustal resistivity structure in the focal region of the 2000Western Tottori Earthquake, Abst. Annu. Conf. Disas. Prev. Res. Inst.2003, P56, 2004 (in Japanese).

  18. Sakamoto, T., N. Yamada, and Y. Suda, Geological map of Japan 1:200,000 Matsue and Taisha, Geological Survey of Japan, 1982.

  19. Sawada, Y., T. Tokuoka, S. Yamauchi, Y. Sampei, and K. Nishimura, A newly discovered Pleistocene volcano in Miho Bay, along the axial zone of the Shinji Rift System, Southwest Japan, J. Geol. Soc. Jpn., 107, 392–405, 2001 (in Japanese with English abstract). Sekiguchi, H. and T. Iwata, Near-source ground motions controlled by source process in the case of the 2000 Tottoriken-Seibu earthquake, Program. Abst., Seism. Soc. Jpn., A73, 2001 (in Japanese).

  20. Shibutani, T., S. Nakao, R. Nishida, F. Takeuchi, K. Watanabe, and Y. Umeda, Swarm-like seismic activity in 1989, 1990 and 1997 preceding the 2000 Western Tottori Earthquake, Earth Planets Space, 54, 831–845, 2002.

  21. Teraoka, Y., H. Matsuura, H. Makimoto, F. Yoshida, M. Kamitani, T. Hiroshima, M. Komazawa, and R. Shichi, Geological map of Japan 1:200,000 Takahashi, Geological Survey of Japan, 1996.

  22. Thurber, C. H., Earthquake locations and three-dimensional crustal structure in the Coyote Lake area, central California, J. Geophys. Res., 88, 8226–8236, 1983.

  23. Thurber, C. H., Local earthquake tomography: velocities and Vp/Vs— theory, in Seismic Tomography, edited by H. M. Iyer and K. Hirahara, 842 pp, Chapman and Hall, London, 1993.

  24. Thurber, C., S. Roecker, W. Ellsworth, Y. Chen, W. Lutter, and R. Sessions, Two-dimensional seismic image of the San Andreas Fault in the Northern Gabilan Range, central California: Evidence for fluids in the fault zone, Geophys. Res. Lett., 24, 1591–1594, 1997.

  25. Tottori Prefectural Government, Investigation of the underground structure in the area related to the 2000 Tottori Seibu Earthquake, 18 pp., Tottori Prefecture, Tottori, 2004 (in Japanese).

  26. Tsukui, M., Temporal variation in chemical composition of phenocrysts and magmatic temperature at Daisen volcano, southwest Japan, J. Volcanol. Geotherm. Res., 26, 317–336, 1985.

  27. Umeda, Y., K. Matsumura, T. Shibutani, S. Ohmi, and H. Katao, The 2000 Western Tottori Earthquake—Precursory swarm earthquake, main shock and aftershock—, J. JSNDS, 19, 501–512, 2001 (in Japanese with English abstract).

  28. Wessel, P. and W. H. F. Smith, Free software helps map and display data, EOS Trans., Am. Geophys. Union, 72, 441, 1991.

  29. Yamanaka, H., Y. Hiramasu and H. Katao, Spatial distribution of atypical aftershocks of the 1995 Hyogo-ken Nanbu earthquake, Earth Planets Space, 54, 933–945, 2002.

  30. Zhao, D., H. Kanamori, H. Negishi, and D. Wiens, Tomography of the source area of the 1995 Kobe Earthquake: Evidence for fluids at the Hypocenter?, Science, 274, 1891–1894, 1996.

Download references

Author information




Corresponding author

Correspondence to Takuo Shibutani.

Additional information

The members of the group are listed at the end of this paper.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Shibutani, T., Katao, H. High resolution 3-D velocity structure in the source region of the 2000 Western Tottori Earthquake in southwestern Honshu, Japan using very dense aftershock observations. Earth Planet Sp 57, 825–838 (2005).

Download citation

Key words

  • The 2000 Western Tottori Earthquake
  • aftershock observation
  • 3-D velocity structure
  • aftershock distribution
  • focal mechanisms