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Highly resolved distribution of aftershocks of the 2007 Noto Hanto Earthquake by a dense seismic observation

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The 2007 Noto Hanto Earthquake occurred on March 25, 2007, in the Noto Peninsula, central Japan. A half day after the main shock, we started installing temporary seismic stations in order to determine the precise locations of its aftershocks. Ten universities and two research institutes deployed 88 temporary seismic stations in and around the source area. The observation lasted for about 2 months. We relocated 1318 aftershocks with arrival time corrections at each station. The relocated hypocenters show relatively small errors—less than 0.2 km in the horizontal direction and less than 0.4 km depth. Most of the relocated hypocenters are about 2.0 km shallower than those determined by JMA. The distribution of the aftershocks forms a southeast-dipping plane. The main shock is located at the bottom part of their distribution. The precise aftershock distribution extends into a shallower area than the original, and it coincides with sea floor-ward extension of the active faults previously known from a sonic reflection survey. Heterogeneous distribution of the aftershocks on the fault plane shows low seismicity just above the main shock hypocenter, and middle-size aftershocks are distributed on the periphery of the main shock. A precursory event (M 4.4) that occurred 0.6 s before the main rupture is located close to the M 2.2 foreshock that occurred 12 min before it.


  1. Douglas, A., Joint epicenter determination, Nature, 215, 47–48, 1967.

  2. 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.

  3. Hokuriku District Eng. Geol. Mapping Com., Engineering Geological Map and manual of Hokuriku District (1:200,000), Kokudo Kaihatsu Gijyutsu Center, 1990.

  4. Iio, Y., S. Matsumoto, T. Matsushima, K. Uehira, H. Katao, S. Ohmi, T. Shibutani, F. Takeuchi, K. Nishigami, B. Enescu, I. Hirose, Y. Kano, Y. Mamada, M. Miyazawa, K. Tatsumi, H. Wada, Y. Kohno, M. Korenaga, T. Ueno, and Y. Yukutake, Generating process of the 2004 Mid Niigata Prefecture Earthquake? Based on the results from the joint online aftershock observation, Zisin, 58, 463–475, 2006.

  5. Katagawa, H., M. Hamada, S. Yoshida, H. Kadosawa, A. Mitsuhashi, Y. Kono, and Y. Kinugasa, Geological development of the west sea area of the Noto Peninsula district in the Neogene Tertiary to Quaternary, central Japan, J. Geogr., 114, 791–810, 2005.

  6. Kato, A., S. Sakai, T. Iidaka, T. Iwasaki, E. Kurashimo, T. Igarashi, N. Hirata, T. Kanazawa, and Group for the aftershock observations of the 2007 Noto Hanto Earthquake, Three-dimensional velocity structure in the source region of the Noto Hanto Earthquake in 2007 imaged by a dense seismic observation, Earth Planets Space, 60, this issue, 105–110, 2008.

  7. Mikumo, T., H. Wada, and M. Koizumi, Seismotectonics of the Hida region, central Japan, Tectonophysics, 147, 95–119, 1988.

  8. National Research Institute for Earth Science and Disaster Prevention (NIED), Earthquake mechanism information,, 2007.

  9. Obara, K., S. Hori, K. Kasahara, Y. Okada, and S. Aoi, Hi-net: High sensitivity seismograph network in Japan, EOS Trans. AGU, 81(48), Fall Meet. Suppl., Abstract S71A-04, 2002.

  10. 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, 417–422, 2005.

  11. Sakai, S., A. Kato, E. Kurashimo, T. Iidaka, T. Igarashi, N. Hirata, T. Iwasaki, T. Kanazawa, S. Watanabe, T. Haneda, M. Kobayashi, K. Miura, R. Miura, K. Tagami, I. Ogino, M. Saka, A. Watanabe, K. Miyakawa, K. Katsumata, H. Takahashi, M. Kasahara, R. Honda, T. Maeda, M. Ichiyanagi, T. Yamaguchi, M. Kosuga, T. Okada, J. Naka-jima, S. Hori, T. Nakayama, K. Nii, A. Hasegawa, T. Kono, S. Suzuki, N. Tsumura, R. Kobayashi, K. Nozaki, Y. Hiramatsu, K. Sugaya, A. Hayashi, T. Hirose, A. Sawada, K. Tanaka, Y. Yamanaka, H. Nakamichi, T. Okuda, Y. Iio, K. Nishigami, M. Miyazawa, H. Wada, N. Hirano, S. Nakao, H. Katao, S. Ohmi, K. Ito, T. Shibutani, Y. Kano, I. Doi, S. Noda, T. Katagi, Y. Nishitsuji, S. Matsumoto, K. Matsushima, A. Saiga, H. Miyamachi, K. Imanishi, Y. Kuwahara, I. Cho, M. Hoshino, T. Takeda, Y. Asano, Y. Yukutake, T. Ueno, T. Maeda, T. Matsuzawa, S. Sekine, M. Matsubara, and K. Obara, Aftershock observation for the Noto Hanto Earthquake in 2007, Bull. Earthq. Res. Inst., 2007 (in Japanese).

  12. Shinohara, M., N. Hirata, and S. Matsuda, Long-term low-power DAT seismic digital data recorder with GPS clock, Zisin, 50, 119–124, 1997 (in Japanese with English abstract).

  13. Urabe, T. and S. Tsukada, A workstation-assisted processing system for waveform data from microearthquake networks, Abstracts of Spring Meeting of Seismological Society of Japan, 70, 1991 (in Japanese).

  14. Wessel, P. and W. H. F. Smith, New version of the generic mapping tools released, EOS Trans. AGU, 76, 329, 1995.

  15. Woessner, J., D. Schorlemmer, S. Wiemer, and P. M. Mai, Spatial correlation of aftershock locations and on-fault main shock properties, J. Geophys. Res., 111, B08301, doi:10.1029/2005JB003961, 2006.

  16. Yamada, T., K. Mochizuki, M. Shinohara, T. Kanazawa, A. Kuwano, K. Nakahigashi, R. Hino, K. Uehira, T. Yagi, N. Takeda, and S. Hashimoto, Aftershock observation of the Noto Hanto earthquake in 2007 using ocean bottom seismometers, Earth Planets Space, 2008 (submitted).

  17. Yamanaka, Y., EIC Seismological Note, Note/2007/EIC185.html, 2007 (in Japanese).

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Correspondence to Shin’ichi Sakai.

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Sakai, S., Kato, A., Iidaka, T. et al. Highly resolved distribution of aftershocks of the 2007 Noto Hanto Earthquake by a dense seismic observation. Earth Planet Sp 60, 83–88 (2008) doi:10.1186/BF03352765

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Key words

  • 2007 Noto Hanto Earthquake
  • urgent aftershock observation
  • dense seismic array
  • precise aftershock distribution