GPS/D-Acoustic survey using closely installed transponders

• Project/Area Number: 17K18799
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Earth and planetary science and related fields
• Research Institution: Tohoku University
• Principal Investigator: Kido Motoyuki 東北大学, 災害科学国際研究所, 教授 (10400235)
• Project Period (FY): 2017-06-30 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000); Fiscal Year 2018: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000); Fiscal Year 2017: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
• Keywords: 海底測地 / 海底GPS / 海底間音響測距 / 海中音速 / 海溝型巨大地震 / 海底断層 / 音響測距 / 海底地殻変動 / GPS-A / ディファレンシャル / 波形読み取り / 地震 / 海洋科学 / 地球観測

Outline of Final Research Achievements

A new approach was proposed and verified that uses acoustic ranging from the sea surface at a site of localized strain of seafloor being expected, where traditional seafloor ranging has difficulty in acoustic paths not to be interfered by seafloor topography. During a sea trial at the reverse fault along the Japan trench, we confirmed that measured accuracy of strain is reasonable and the no significant strain was observed for the campaign period. On the contrary, during a sea trial off the Kii-peninsula, extremely complicated temperature perturbation was observed, which cannot adequately be corrected for. This indicated that the proposed approach is not always applicable to all the possible seafloor conditions and should be assessed beforehand.

Academic Significance and Societal Importance of the Research Achievements

本研究では、従来の手法が適用困難な海底地形が急峻な場所でも局所変形の計測が可能となる新手法を提案し、実観測で実用性を検証するものである。考案した手法を適用した日本海溝の観測点では、理論的な予測に従った計測精度で変形のモニタリングに成功し、今後同様の場所に適用することで、海溝型巨大地震の予測に役立つことが分かった。一方で、海底付近の海水の擾乱の激しい箇所では必要な計測精度を達成できないことも判明し、事前に擾乱の度合いを把握した上で、適切に観測点を選択する重要性が明らかになった。

Research Products

• [Journal Article] Seafloor geodesy revealed partial creep of the North Anatolian Fault submerged in the Sea of Marmara (2019)
  • Author(s): Yamamoto, R., M. Kido, Y. Ohta, N. Takahashi, Y. Yamamoto, A. Pinar, D. Kalafat, H. Ozener, and Y. Kaneda
  • Journal Title: Geophysical Research Letters Volume: 46 Issue: 3 Pages: 1268-1275
  • DOI: 10.1029/2018gl080984
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Onboard Realtime Processing of GPS-Acoustic Data for Moored Buoy-Based Observation (2018)
  • Author(s): Kido, M., M. Imano, Y. Ohta, T. Fukuda, N. Takahashi, S. Tsubone, Y. Ishihara, H. Ochi, K. Imai, C. Honsho, and R. Hino
  • Journal Title: Journal of Disaster Research Volume: 13 Issue: 3 Pages: 472-488
  • DOI: 10.20965/jdr.2018.p0472
  • NAID: 130007406104
  • ISSN: 1881-2473, 1883-8030
  • Year and Date: 2018-06-01
  • Peer Reviewed / Open Access
• [Journal Article] Along-trench variation in seafloor displacements after the 2011 Tohoku earthquake (2017)
  • Author(s): Tomita, F, M. Kido, Y. Ohta, T. Iinuma and R. Hino
  • Journal Title: Science Advances Volume: 3 Issue: 7 Pages: 1-7
  • DOI: 10.1126/sciadv.1700113
  • Peer Reviewed / Open Access
• [Journal Article] Comprehensive Analysis of Traveltime Data Collected Through GPS-Acoustic Observation of Seafloor Crustal Movements (2017)
  • Author(s): Honsho, C., and M. Kido
  • Journal Title: J. Geophys. Res. Volume: 122 Issue: 10 Pages: 1-17
  • DOI: 10.1002/2017jb014733
  • Peer Reviewed
• [Presentation] GPS-音響測距観測の短周期変動と海中内部重力波について (2018)
  • Author(s): 木戸 元之，松井 凌，本荘 千枝
  • Organizer: 日本地球惑星科学連合2018年大会
• [Presentation] 海中音速の水平勾配を考慮した海底地殻変動観測のアレイ解析 (2018)
  • Author(s): 本荘 千枝，木戸 元之，富田 史章
  • Organizer: 日本地球惑星科学連合2018年大会
• [Presentation] Direct measurement of postseismic motion of incoming Pacific plate after the 2011 Tohoku Earthquake using acoustic ranging system (2018)
  • Author(s): Yamamoto, R., R. Hino, M. Kido, Y. Osada, and C. Honsho
  • Organizer: European Geosciences Union General Assembly 2018
  • Int'l Joint Research
• [Presentation] Effect of tidal internal wave on GNSS-Acoustic positioning (2018)
  • Author(s): Matsui, R., and M. Kido
  • Organizer: American Geophysical Union Fall Meeting 2018
  • Int'l Joint Research
• [Presentation] Seafloor geodetic survey revealed partial creep of North Anatolian Fault at the western part of the Sea of Marmara, Turkey (2017)
  • Author(s): Kido, M., R. Yamamoto, Y. Ohta, N. Takahashi, Y. Yamamoto, D. Kalafat, A. Pinar, H. Ozener, S. Ozeren, Y. Kaneda
  • Organizer: EGU General Assembly 2017
  • Int'l Joint Research
• [Presentation] XBT集中観測で見られた短周期内部重力波とGPS音響測距観測に与える影響 (2017)
  • Author(s): 木戸元之, 松井凌, 今野美冴, 本荘千枝
  • Organizer: JpGU-AGU Joint Meeting 2017
• [Presentation] Short-period ocean fluctuation induced by internal wave and its effect on GNSS/acoustic analysis (2017)
  • Author(s): Kido, M., R. Matsui, M. Imano, C. Honsho
  • Organizer: IAG-IASPEI 2017
  • Int'l Joint Research
• [Presentation] Short period sound speed oscillation measured by intensive XBT survey and its role on GNSS/acoustic positioning (2017)
  • Author(s): Kido, M., R. Matsui, M. Imano, C. Honsho
  • Organizer: 2017 AGU Fall meeting
  • Int'l Joint Research