1887

Abstract

Summary

The Nankai Trough, Japan is a major subduction zone, and huge mega-thrust earthquake repeatedly occurred. In this area, DONET (Dense Oceanfloor Network systems for Earthquake and Tsunamis) seafloor cabled seismic network, and IODP C0002G borehole observatory were distributed. In KR13–17 cruise, conducted by R/V Kairei in November 2013, we performed an experimental survey using DONET and IODP C0002G seismometers and airgun shooting to estimate seismic anisotropy in the Nankai Trough. Seismic anisotropy can be a proxy of stress state, which would be a key parameter governing its fault dynamics triggering mega-thrust earthquake in the subduction zone. In KR13–17 cruise, we performed airgun circle shooting around DONET and IODP C0002G seismometers. Then we computed radial and transverse components for each shot-receiver azimuth from original horizontal records of seismometers. In radial and transverse components, P-S converted waves reflected from the bottom of shallow sediment layers were clearly visible. We then obtained azimuthal seismic anisotropy below seismometers in shallow sediment. Obtained results have good agreement with results from another method and dataset. We plan to conduct next survey in the same survey lines to detect temporal evolution of the seismic anisotropy in the seismogenic subduction zone.

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/content/papers/10.3997/2214-4609.201413354
2015-06-01
2024-03-29
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References

  1. Seno, T., Stein, S. and Gripp, E., A.
    [1993] A model for the motion of the Philippine Sea plate consistent with NUVEL-1 and geological data. Journal of Geophysical Research, 89, 17941–17948.
    [Google Scholar]
  2. Kaneda, K.
    [2010] The advanced ocean floor real time monitoring system for mega thrust earthquakes and tsunamis-Application of DONET and DONET2 data to seismological research and disaster mitigation. Proceedings of OCEANS 2010, 1–4, CD-ROM.
    [Google Scholar]
  3. Kopf, A., Araki, E., Toczko, S.
    and the Expedition 332 Scientists [2011] Proceedings of the Integrated Ocean Drilling Program, 332, CD-ROM.
    [Google Scholar]
  4. Nakano, M., Tonegawa, T. and Kaneda, Y.
    [2012] Orientations of DONET seismometers estimated from seismic waveforms, JAMSTEC Report of Research and Development, 15, 77–89. (in Japanese with English abstract)
    [Google Scholar]
  5. Kimura, T., Araki, E., Kawaguchi, K. and Kaneda, Y.
    [2014] Performance of borehole seismometers installed in the C0002G observatory at the Nankai Trough, Japan. Proceedings of OCEANS 2014 Taipei, 1–4, CD-ROM.
    [Google Scholar]
  6. Haacke, R. R. and WestbrookG. K.
    [2006] A fast, robust method for detecting and characterizing azimuthal anisotropy with marine PS converted waves, and its application to the west Svalbard continental slope. Geophysical Journal International, 167, 1402–1412.
    [Google Scholar]
  7. Tsuji, T., Hino, R., Sanda, Y., Yamamoto, K., Park, J. O., No, T., Araki, E., Bangs, N., Huence, R., Moore, G., Kinoshita, M.
    [2011] In situ stress state from walkaround VSP anisotropy in the Kumano basin southeast of the Kii Peninsula, Japan. Geochemistry Geophysics Geosystems, 12.
    [Google Scholar]
  8. Araki, E., Kimrua, T., Kodaira, S., Miura, S., Takaesu, M., Takahashi, N., Nakano, M. and Kaneda, Y.
    [2013] Experiment to detect temporal change of seismic velocity in the subducting plate boundary in the Nankai Trough using the DONET submarine cabled observation network and airgun controlled source. Proceedings of OCEANS 2014 Taipei, 1–4, CD-ROM.
    [Google Scholar]
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