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Volume 54 Supplement 11

Special Issue: Slip and Flow Processes in and below the Seismogenic Region

Deep structure of the Nagamachi-Rifu fault deduced from small aperture seismic array observations


A seismic reflection survey using both explosives and vibrators was conducted in June 2001 around the Nagamachi-Rifu fault, northeastern Japan. We carried out observations of four small aperture seismic arrays in the area to reveal detailed structures of the fault. Array analysis was applied to waveform data from 15 explosives to obtain P-wave scatterer distributions in the area. The obtained P-wave scatterer distribution correlates in space with microearthquake activities and heterogeneous structures such as S-wave reflectors, a structure of caldera, and Mohorovicic discontinuity. We could also image that a sub-horizontal layer with a length of about 10 km exists in the deep extension of the Nagamachi-Rifu fault beneath the seismogenic layer.


  • Christopher, S. L. and T. Lay, Inversion of P coda for isotoropic scatters at the Yucca Flat test site, Bull. Seism. Soc. Am., 79, 790–804, 1989.

    Google Scholar 

  • Hasegawa, A., H. Ito, T. Iwasaki, and T. Ikawa, Deep structure of Nagamachi-Rifu fault as inferred from seismic expeditions, the Proceedings of the International Symposium on Slip and Flow Processes in and Below the Seismogenic Region, 67–72, 2001.

  • Hickman, S., R. Sibson, and R. Bruhn, Introduction to special section: Mechanical involvement of fluids in faulting, J. Geophys. Res., 100, 12831–12840, 1995.

    Article  Google Scholar 

  • Hori, S., N. Umino, Y. Asano, and A. Hasegawa, S-wave reflectors in the crust of northeastern Japan, Prog. Abstr. Seism. Soc. Japan 1999 Fall meeting, P140, 1999 (in Japanese).

  • Iio, Y., A possible generating process of the 1995 Southern Hyogo Prefecture earthquake, J. Seism. Soc. Japan, 49, 103–112, 1996 (in Japanese with English abstract).

    Google Scholar 

  • Ikeda, Y., Japanese thrust faults: A possibility of flake tectonics, Monthly Chikyu, Extra 5, 1992 (in Japanese).

  • Ito, T., Will the median tectonic line move?; A new discovery of crustal structure, Zisin Journal, 17, 27–32, 1994 (in Japanese).

    Google Scholar 

  • Komatsubara, T. and Y. Awata, Analyses of pre-, co-, and post-seismic vertical crustal movement on the southeastern Akita Earthquake of 1970—An evidence of pre-slip at the base of the seismogenic layer, J. Seism. Soc. Japan, 54, 33–44, 2001 (in Japanese with English abstract).

    Google Scholar 

  • Kuwahara, Y., H. Ito, H. Kawakatsu, T. Ohminato, and T. Kiguchi, Crustal heterogeneity as inferred from seismic coda wave decomposition by small-aperture array observation, Phys. Earth Planet. Inter., 104, 247–256, 1997.

    Article  Google Scholar 

  • Makovsky, Y. and S. L. Klemperer, Measuring the seismic properties of Tibetan bright spots: Evidence for free aqueous fluids in the Tibetan middle crust, J. Geophys. Res., 104, 10795–10825, 1999.

    Article  Google Scholar 

  • Matsumoto, S. and A. Hasegawa, Distinct S wave reflector in the midcrust beneath Nikko-Shirane volcano in the northeastern Japan arc, J. Geophys. Res., 101, 3067–3083, 1996.

    Article  Google Scholar 

  • Matsumoto, S., K. Obara, and A. Hasegawa, Imaging P-wave scatter distribution in the focal area of the 1995 M7.2 Hyogo-ken Nanbu (Kobe) Earthquake, Geophys. Res. Lett., 25, 1439–1442, 1998.

    Article  Google Scholar 

  • Nakamura, A., Y. Asano, and A. Hasegawa, Estimation of deep fault geometry of the Nagamachi-Rifu fault from seismic array observations, Earth Planets Space, 54, this issue, 1027–1031, 2002.

    Article  Google Scholar 

  • Neidell, N. S. and M. T. Tarner, Semblance and other coherency measures for multichannel data, Geophysics, 36, 482–497, 1971.

    Article  Google Scholar 

  • Nishimura, T., T. Sagiya, T. Tada, and S. Miura, High strain rate west of the Nagamachi-Rifu fault, northern Japan, observed by a dense GPS array, the Proceedings of the International Symposium on Slip and Flow Processes in and Below the Seismogenic Region, 357–362, 2001.

  • Okada, Y., K. Kasahara, S. Hori, K. Obara, and S. Aoi, Hi-net (1): Outline, Prog. Abstr. Seism. Soc. Japan 2000 Fall meeting, P004, 2000.

  • Research Group for Active Faults of Japan, Active Faults of Japan, University of Tokyo Press, Tokyo, 1991 (in Japanese).

    Google Scholar 

  • Revenaugh, J., Relation of the 1992 Landers, California, earthquake sequence to seismic scattering, Science, 270, 1344–1347, 1995.

    Article  Google Scholar 

  • Sagiya, T., T. Nishimura, S. Miura, Y. Iio, and T. Tada, Investigation of slip at deep extension of fault using dense GPS array observations, Monthly Chikyu, 23, 321–327, 2001.

    Google Scholar 

  • Sanford, A. R., O. Alptekin, and T. R. Toppozada, Use of reflection phases on microearthquake seismograms to map an unusual discontinuity beneath the Rio Grande Rift, Bull. Seism. Soc. Am., 63, 2021–2034, 1973.

    Google Scholar 

  • Sato, H. and N. Hirata, Deep structure of active faults and evolution of the Japanese islands, Kagaku, 68, 63–71, 1998 (in Japanese).

    Google Scholar 

  • Spudich, P. and T. Bostwick, Studies of the seismic coda using an earthquake cluster as a deeply buried seismograph array, J. Geophys. Res., 92, 10526–10546, 1987.

    Article  Google Scholar 

  • Takenaka, H., A scheme for estimating the location and tangential plane of a reflector, Earth Planets Space, 52, 299–303, 2000.

    Article  Google Scholar 

  • Umino, N., T. Okada, and A. Hasegawa, Foreshock and aftershock sequence of 1998 M5.0 Sendai, northeastern Japan, earthquake and its implications for earthquake nucleation, Bull. Seism. Soc. Am., 2002 (in press).

  • Umino, N., H. Ujikawa, S. Hori, and A. Hasegawa, Distinct S-wave reflectors (bright spots) detected beneath the Nagamachi-Rifu fault, NE Japan, Earth Planets Space, 54, this issue, 1021–1026, 2002.

    Article  Google Scholar 

  • Wagner, G. S., Local wave propagation near the San Jacinto fault zone, southern California: Observations from a three-component seismic array, J. Geophys. Res., 103, 7231–7246, 1998.

    Article  Google Scholar 

  • Wessel, P. and W. H. F. Smith, Free software helps map and display data, EOS Trans. AGU, 72, 441, 445–446, 1991.

    Article  Google Scholar 

  • Yokokura, T., T. Miyazaki, T. Urabe, N. Kano, K. Yamaguchi, T. Kiguchi, A. Tanaka, T. Yokota, M. Komazawa, Y. Kuwahara, Y. Ogawa, Y. Mitsuhata, I. Hasegawa, H. Kato, Y. Watanabe, K. Nakamura, and H. Ito, Deep seismic profiling in Japan, Study on deep crust, 9–27, 2000 (in Japanese with English abstract).

  • Yoshida, T., The evolusion of arc magmatism in the NE Honshu arc, Japan, Tohoku Geophys. J., 36, 131–149, 2001.

    Google Scholar 

  • Yoshimoto, K., N. Uchida, H. Sato, M. Ohtake, N. Hirata, and K. Obara, Microseismicity around the Nagamachi-Rifu fault, Miyagi prefecture, Northern Japan, J. Seism. Soc. Japan, 52, 407–416, 2000 (in Japanese with English abstract).

    Google Scholar 

  • Yoshimoto, K., T. Okada, and A. Hasegawa, Local crustal structure around the Nagamachi-Rifu fault derived from receiver functions, the Proceedings of the International Symposium on Slip and Flow Processes in and Below the Seismogenic Region, 73–76, 2001.

  • Zhao, D., S. Horiuchi, and A. Hasegawa, 3-D seismic velocity structure of the crust and the uppermost mantle in the northeastern Japan arc, Tectonophys., 181, 135–149, 1990.

    Article  Google Scholar 

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Correspondence to Kazutoshi Imanishi.

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Imanishi, K., Ito, H., Kuwahara, Y. et al. Deep structure of the Nagamachi-Rifu fault deduced from small aperture seismic array observations. Earth Planet Sp 54, 1033–1038 (2002).

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  • Seismogenic Zone
  • Detachment Fault
  • Seismic Array
  • Shot Point
  • Aseismic Slip