Details of the Researcher

PHOTO

Fumiaki Tomita
Section
International Research Institute of Disaster Science
Job title
Assistant Professor
Degree

  • 博士（理学）（東北大学）

  • 修士（理学）（東北大学）

e-Rad No.
20838916

Research History 4

  • 2021/07 - Present
    International Research Institute of Disaster Science (IRIDeS), Tohoku University　Subduction Earthquake Lab, Risk Evaluation and Disaster Mitigation Research Division　Assistant Professor

  • 2019/04 - 2021/06
    Japan Agency for Marine-Earth Science and Technology　Research Institute for Marine Geodynamics　Postdoctral Researcher

  • 2018/09 - 2019/03
    Hokkaido University　Graduate School of Science　Part-time researcher

  • 2018/04 - 2018/09
    International Research Institute of Disaster Science, Tohoku University　Research Fellowship for Young Scientists (PD), Japan Society for the Promotion of Science

Education 2

  • Tohoku University　Graduate School of Science　Geophysics

    2013/04 - 2018/03

  • Tohoku University　Faculty of Science　Department of Geophysics

    2009/04 - 2013/03

Committee Memberships 11

  • Japan Geoscience Union　Ocean Floor Geoscience Focus Group, Committee member

    2023/05 - Present

  • 日本測地学会　編集事務

    2022/06 - Present

  • Geodetic Society of Japan　Councillor

    2023/06 - 2025/05

  • Japan Geoscience Union　JpGU2024 Session Convener (Crustal deformation)

    2023/10 - 2024/06

  • 日本地震学会　「地震」編集委員

    2022/04 - 2024/03

  • Geodetic Society of Japan　Program Committee for Fall Meeting 2023

    2023/06 - 2023/11

  • Japan Geoscience Union　JpGU2023 Session Convener (Crustal deformation)

    2022/10 - 2023/06

  • 日本測地学会　JpGUプログラム委員

    2021/06 - 2023/05

  • 日本地震学会　地震学夏の学校2022実行臨時委員会委員

    2021/12 - 2022/10

  • Japan Geoscience Union　JpGU2022 Session Convener (Crustal deformation)

    2021/10 - 2022/06

  • Japan Geoscience Union　JpGU2021 Session Convener (Crustal deformation)

    2020/11 - 2021/06

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Professional Memberships 5

  • Japan Society for Disaster Information Studies

    2017 - 2020

  • JAPAN GEOSCIENCE UNION

  • American Geophysical Union

  • The Geodetic Society of Japan

  • THE SEISMOLOGICAL SOCIETY OF JAPAN

Research Interests 3

  • Earthquake

  • Crustal Deformation

  • Seafloor Geodesy

Research Areas 1

  • Natural sciences / Solid earth science /

Awards 8

  1. Excellent Reviewers in 2024

    2025/02　Earth, Planets and Space

  2. 2024年度若手学術奨励賞

    2024/08　日本地震学会　海底測地観測に基づいた沈み込み帯プレート境界すべりの解明

  3. Excellent Reviewers in 2023

    2024/02　Earth, Planets and Space

  4. Paper Award 2022

    2023/03　The Seismological Society of Japan　Improvement on spatial resolution of a coseismic slip distribution using postseismic geodetic data through a viscoelastic inversion

  5. 第十三回泉萩会奨励賞

    2021/09　東北大学物理系同窓会「泉萩会」　2011年東北沖地震に伴う海底地殻変動場の推定とそのモデル化

  6. Research Spotlight

    2021/06　Eos　Development of a Trans-Dimensional Fault Slip Inversion for Geodetic Data

  7. Highlights

    2016/01　Geophysical Research Letters

  8. Prominent Student Presentation Award, 122th Meeting of the Geodetic Society of Japan

    2014/11　The Geodetic Society of Japan

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Papers 24

  1. A Thin and Weak Lithosphere-Asthenosphere Boundary (LAB) Beneath the Oceanic Lithosphere and its Effects on Subduction Earthquake Cycle Deformation

    Tianhaozhe Sun, Kelin Wang, Jiangheng He, Fumiaki Tomita, Takeshi Iinuma, Ryota Hino, Motoyuki Kido, Yusaku Ohta

    2025/03/18

    DOI： 10.5194/egusphere-egu25-13084 　

  2. Seafloor Crustal Deformation Observations Utilizing Unmanned Surface Vehicles for Monitoring Fault Locking and Sliding Processes at Subduction Zone Plate Boundaries

    Takeshi Iinuma, Motoyuki Kido, Tatsuya Fukuda, Yusaku Ohta, Fumiaki Tomita, Ryota Hino, Hiroaki Takahashi, Takane Hori, Yusuke Yokota

    2025 IEEE Underwater Technology (UT)　1-5　2025/03/02

    Publisher: IEEE

    DOI： 10.1109/ut61067.2025.10947368 　

  3. GNSS-Acoustic positioning error in the vertical component considering the uncertainty of a reference sound speed profile Peer-reviewed

    Fumiaki Tomita, Motoyuki Kido, Takeshi Iinuma, Yusaku Ohta

    Marine Geophysical Research　46　(1)　2025/02/18

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s11001-025-09563-w 　

    ISSN： 0025-3235

    eISSN： 1573-0581

    More details Close

    Abstract The precise detection of seafloor crustal deformation is important for understanding various tectonic phenomena, especially the deformation process associated with a seismic cycle. Global Navigation Satellite System–Acoustic (GNSS-A) positioning enables the measurement of horizontal and vertical seafloor deformations. However, vertical motion detected by GNSS-A positioning often has various systematic biases; therefore, the positioning error of vertical motion is typically worse than that of horizontal motion. In this study, we examined one of the systematic bias sources originating from the uncertainty of the reference sound speed profile (SSP) employed in GNSS-A positioning. Using direct oceanographic measurement data, we addressed the uncertainties of using a reference SSP in both cases, where the reference SSP was obtained from direct measurement and the oceanographic data assimilation model (JCOPE2M). We then examined the vertical GNSS-A positioning errors in both cases using the Monte Carlo method: ~2 and ~6 cm in the former and latter cases, respectively. Moreover, we optimized the vertical GNSS-A positioning errors by considering the uncertainty of a reference SSP and other error sources. The optimized vertical GNSS-A positioning errors successfully explain offsets of the campaign solutions deviated from a long-term displacement trend compared with the conventional error evaluations. Although this study focused on the uncertainty of a reference SSP, it is important to carefully evaluate various other systematic error sources to precisely detect vertical seafloor motion.

  4. Enhanced GNSS-acoustic positioning method implementing with constraints on underwater sound speed structure Peer-reviewed

    Fumiaki Tomita

    Earth, Planets and Space　2024/12/27

    DOI： 10.1186/s40623-024-02120-6 　

  5. Revisiting Slip Deficit Rates and Its Insights Into Large and Slow Earthquakes at the Nankai Subduction Zone Peer-reviewed

    Raymundo Plata‐Martinez, Takeshi Iinuma, Fumiaki Tomita, Yasuyuki Nakamura, Takuya Nishimura, Takane Hori

    Journal of Geophysical Research: Solid Earth　129　(12)　2024/12/20

    Publisher: American Geophysical Union (AGU)

    DOI： 10.1029/2023jb027942 　

    ISSN： 2169-9313

    eISSN： 2169-9356

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    Abstract The Nankai subduction zone presents significant seismic and tsunami risks, given its historical earthquakes exceeding magnitude 8 and the expectations of similar future events. Slow earthquakes, common at the shallow and deep plate interface, result from different frictional properties linked to interplate slip deficit accumulation. This study estimates slip deficit rates at the Nankai subduction zone using land and ocean‐bottom geodetic data. Previous estimates encountered limitations, often smoothing slip deficits, omitting observational error differences between ocean‐floor and land data, and relying on homogeneous structure models. To address these issues, we employ a novel trans‐dimensional reversible jump Markov Chain Monte Carlo algorithm. This approach dynamically adjusts slip parameters, accommodating data resolution and producing a flexible slip distribution without predetermined spatial constraints. Additionally, it automatically weights data for observational errors and integrates elastic Green functions from a 3D structure of the Nankai region. Our results provide a finer, heterogeneous slip distribution, improving estimates in inland regions. However, limitations remain offshore in areas with sparse data. We revised the spatial distribution of Nankai slow earthquakes and confirmed a good agreement with intermediate slip deficit rates, identifying coupled and uncoupled regions. High slip deficit rates align with rupture areas of historic large earthquakes. Slow earthquakes occur at frictionally weak plate interfaces, and shallow slow earthquakes may result from subducting relief heterogeneities with important pore fluid pressure effects. We introduce an updated distribution of slip deficit rates for the Nankai subduction zone, considering observed slip deficit rates and the fast and slow earthquake occurrence.

  6. A new GNSS-acoustic positioning software implementing multiple positioning functions considering nadir total delays Peer-reviewed

    Fumiaki Tomita, Motoyuki Kido

    Earth, Planets and Space　76　(1)　2024/03/26

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1186/s40623-024-01987-9 　

    eISSN： 1880-5981

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    Abstract Global navigation satellite system-acoustic (GNSS-A) positioning is an important geodetic observation technique for detecting seafloor crustal deformation. After the 2011 Tohoku–Oki earthquake, GNSS-A observational networks were extended along various subduction zones, and observational systems have been improved, especially for sea surface platforms, such as the introduction of an unmanned vehicle, the Wave Glider. The aforementioned development of GNSS-A observations has provided a large amount of observational data. Furthermore, GNSS-A positioning methods were recently developed considering the lateral heterogeneity of the sound speed structure. Thus, it is important to develop a software that makes it easy for widespread use of the latest GNSS-A positioning methods. However, there is currently only one open-source GNSS-A positioning software, which may hinder the entry of various researchers into GNSS-A positioning analyses. Here, we developed a new GNSS-A positioning software, henceforth called “SeaGap” (Software of enhanced analyses for GNSS-acoustic positioning), that executes various positioning methods from the conventional kinematic positioning technique to the latest Markov Chain Monte Carlo (MCMC)-based static positioning technique. We introduce their methodology and demonstrate its application to actual observational data. The software newly added optional prior distributions to the unknown parameters expressing the heterogeneity of a sound speed structure into the MCMC-based static positioning method, and we also applied the new method to actual observational data. In addition to the positioning functions, the software contains various auxiliary functions, including drawing. The developed software is written using the “Julia” language and is distributed as an open-source software. Graphical Abstract

  7. The slip deficit rate, slow and fast earthquake at the Nankai subduction zone

    Raymundo Omar, Plata Martinez, Takeshi Iinuma, Fumiaki Tomita, Takuya Nishimura, Takane Hori

    2023/05/15

    DOI： 10.5194/egusphere-egu23-15859 　

  8. USV-Observed Turbulent Heat Flux Induced by Late Spring Cold Dry Air Incursion over Sub-Mesoscale Warm Regions off Sanriku, Japan Invited Peer-reviewed

    Akira Nagano, Takuya Hasegawa, Keisuke Ariyoshi, Takeshi Iinuma, Tatsuya Fukuda, Nobuhiro Fujii, Fumiaki Tomita, Ryota Hino

    Sensors　22　(24)　9695　2022/12/10

    DOI： 10.3390/s22249695 　

  9. An approximate travel time calculation and a robust GNSS-acoustic positioning method using an MCMC technique Peer-reviewed

    Fumiaki Tomita, Motoyuki Kido

    Earth, Planets and Space　74　(1)　2022/12/02

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1186/s40623-022-01740-0 　

    eISSN： 1880-5981

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    Abstract It is important to consider horizontal heterogeneity in an underwater sound speed structure to accurately estimate positions of GNSS-acoustic sites. Although large amounts of moving survey data (a sea-surface platform moves around when acoustic signals are transmitted) are required to accurately detect a sloping sound speed structure, the actual observational data do not necessarily include sufficient moving survey data due to sea conditions or observational time. To treat these insufficient data, it was assumed that a shallow sound speed gradient was continuously present up to a fixed water depth (gradient depth). However, the validity of this assumption has not been investigated, and the gradient depth has not been optimized. In this study, we developed a new GNSS-acoustic array positioning method that optimizes the gradient depth using an MCMC technique. To employ this technique, we also developed an approximate technique for rapidly calculating travel time, because the conventional travel time calculation requires high computational cost for integration into the MCMC technique. We assessed the performance of the approximate travel time calculation technique and demonstrated its sufficient accuracy and precision for estimating array positions. Then, we applied the new GNSS-acoustic array positioning method to the actual observational data collected by the Japan Coast Guard and Tohoku University. Using enough amounts of the moving survey data, our method demonstrated the results comparable with the conventional GNSS-acoustic positioning method estimating a sloping sound speed structure; thus, the assumption of the sound speed gradient with the fixed water depth was valid. Moreover, due to the physical restriction of this assumption, our method provided robust solutions even when the observational data contained small quantities of moving survey data with a simple sea-surface track. Although our method still cannot be used in the scenario, where no moving survey data are available, it can work robustly compared with the conventional methods. Graphical Abstract

  10. Impact of employing a waveglider on GNSS-Acoustic survey along the Japan trench

    Motoyuki Kido, Chie Honsho, Fumiaki Tomita, Yusaku Ohta, Ryota Hino, Takeshi Iinuma

    2022/03/27

    Publisher: Copernicus {GmbH}

    DOI： 10.5194/egusphere-egu22-2138 　

  11. Development of a Trans‐Dimensional Fault Slip Inversion for Geodetic Data Peer-reviewed

    Fumiaki Tomita, Takeshi Iinuma, Ryoichiro Agata, Takane Hori

    Journal of Geophysical Research: Solid Earth　126　(5)　2021/05

    Publisher: American Geophysical Union ({AGU})

    DOI： 10.1029/2020JB020991 　

    ISSN： 2169-9313

    eISSN： 2169-9356

  12. GNSS-Acoustic Observations of Seafloor Crustal Deformation Using a Wave Glider Peer-reviewed

    Takeshi Iinuma, Motoyuki Kido, Yusaku Ohta, Tatsuya Fukuda, Fumiaki Tomita, Iwao Ueki

    Frontiers in Earth Science　9　2021/03/11

    Publisher: Frontiers Media {SA}

    DOI： 10.3389/feart.2021.600946 　

    ISSN： 2296-6463

    eISSN： 2296-6463

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    Crustal deformation of the seafloor is difficult to observe solely using global navigation satellite system (GNSS). The GNSS-acoustic (GNSS-A) technique was developed to observe seafloor crustal deformation, and it has produced a steady series of successful observations with remarkable results related to crustal deformation associated with huge earthquakes around the Japanese Islands. However, utilizing GNSS-A incurs very large financial and human costs as it requires the use of a research vessel as a surface platform and has a limited observation frequency, which is less than once a year at seafloor stations along the Japan Trench. To conduct frequent observations, an automatic GNSS-A data acquisition system was developed that operates via an unmanned surface vehicle (wave glider). The first observations using this system were performed at a seafloor station off Aomori Prefecture in July 2019. The wave glider was equipped with two GNSS antennas, an acoustic transducer, a microelectromechanical system gyroscope, and associated control and logging units. Data acquisition and autonomous activation of the seafloor stations were successfully executed by controlling the power supply to the payload via satellite communication with the wave glider. The glider rarely strayed off the configured course and the solar panels generated sufficient power to perform the observations although the weather was mostly cloudy. The GNSS-A data processing results show that the position of the station was determined with the same accuracy and precision as in previous observations performed using a research vessel.

  13. Improvement on spatial resolution of a coseismic slip distribution using postseismic geodetic data through a viscoelastic inversion Peer-reviewed

    Fumiaki Tomita, Takeshi Iinuma, Yusaku Ohta, Ryota Hino, Motoyuki Kido, Naoki Uchida

    Earth, Planets and Space　72　(1)　2020/06

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1186/s40623-020-01207-0 　

    ISSN： 1343-8832

    eISSN： 1880-5981

  14. Development of a kinematic GNSS-Acoustic positioning method based on a state-space model Peer-reviewed

    Fumiaki Tomita, Motoyuki Kido, Chie Honsho, Ryo Matsui

    Earth, Planets and Space　71　(1)　2019/12

    Publisher: Springer Science and Business Media {LLC}

    DOI： 10.1186/s40623-019-1082-y 　

  15. Offshore Postseismic Deformation of the 2011 Tohoku Earthquake Revisited: Application of an Improved GPS-Acoustic Positioning Method Considering Horizontal Gradient of Sound Speed Structure Peer-reviewed

    C. Honsho, M. Kido, F. Tomita, N. Uchida

    Journal of Geophysical Research: Solid Earth　124　(6)　5990-6009　2019/06

    DOI： 10.1029/2018JB017135 　

    ISSN： 2169-9313

    eISSN： 2169-9356

  16. A study on the co- and post-seismic deformation of the 2011 Tohoku-oki earthquake inferred from GPS-acoustic observations

    Tomita, F

    Tohoku University　2018/03

  17. Learning from crustal deformation associated with the M9 2011 Tohoku-oki earthquake Peer-reviewed

    Kelin Wang, Tianhaozhe Sun, Lonn Brown, Ryota Hino, Fumiaki Tomita, Motoyuki Kido, Takeshi Iinuma, Shuichi Kodaira, Toshiya Fujiwara

    Geosphere　14　(2)　552-571　2018/02/24

    Publisher: Geological Society of America

    DOI： 10.1130/GES01531.1 　

    ISSN： 1553-040X

  18. Seafloor Geodetic Observations to Reveal Co- and Post-Seismic Slip Distributions of the 2011 Tohoku-Oki Earthquake Peer-reviewed

    Tomita, F, Ohta, Y, Iinuma, T, Hino, R, Kido, M, Uchida, N

    2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)　1-4　2018

    DOI： 10.1109/OCEANSKOBE.2018.8559370 　

  19. Along-trench variation in seafloor displacements after the 2011 Tohoku earthquake Peer-reviewed

    Fumiaki Tomita, Motoyuki Kido, Yusaku Ohta, Takeshi Iinuma, Ryota Hino

    SCIENCE ADVANCES　3　(7)　e1700113　2017/07

    DOI： 10.1126/sciadv.1700113 　

    ISSN： 2375-2548

  20. Analysis of “Disaster Mitigation Action Card Game” on educational effect for junior and junior high school students by questionnaire surveys Peer-reviewed

    Tomita, F, R. Oyanagi, A. Hisamatsu, S. Yamada, S. Ishibashi, S. Watanabe, R. Kaneko, H. Anzai, M. Kuri

    Journal of Disaster Information Studies　15　(2)　207-220　2017

    DOI： 10.24709/jasdis.15.2_207 　

    ISSN： 1348-3609 2433-7382

  21. Progress in the project for development of GPS/acoustic technique over the last 4 years Peer-reviewed

    Motoyuki Kido, Hiromi Fujimoto, Ryota Hino, Yusaku Ohta, Yukihito Osada, Takeshi Iinuma, Ryosuke Azuma, Ikuko Wada, Satoshi Miura, Syuichi Suzuki, Fumiaki Tomita, Misae Imano

    International Association of Geodesy Symposia　145　3-10　2017

    Publisher: Springer Verlag

    DOI： 10.1007/1345_2015_127 　

    ISSN： 0939-9585

  22. Development and examination of new algorithms of traveltime detection in GPS/acoustic geodetic data for precise and automated analysis Peer-reviewed

    Ryosuke Azuma, Fumiaki Tomita, Takeshi Iinuma, Motoyuki Kido, Ryota Hino

    EARTH PLANETS AND SPACE　68　(143)　2016/08

    DOI： 10.1186/s40623-016-0521-2 　

    ISSN： 1880-5981

  23. First measurement of the displacement rate of the Pacific Plate near the Japan Trench after the 2011 Tohoku-Oki earthquake using GPS/acoustic technique International-journal Peer-reviewed

    Fumiaki Tomita, Motoyuki Kido, Yukihito Osada, Ryota Hino, Yusaku Ohta, Takeshi Iinuma

    GEOPHYSICAL RESEARCH LETTERS　42　(20)　8391-8397　2015/10

    DOI： 10.1002/2015GL065746 　

    ISSN： 0094-8276

    eISSN： 1944-8007

  24. A study of postseismic deformation following the 2011 Tohoku-oki Earthquake based on seafloor geodetic observations

    Tomita, F

    Tohoku University　2015/03

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Misc. 7

  1. GNSS-Acoustic Observation Using the Wave Glider to Detect the Seafloor Crustal Deformation (3)

    飯沼卓史, 木戸元之, 福田達也, 太田雄策, 富田史章, 有吉慶介, 永野憲, PLATA-MARTINEZ Raymundo, 日野亮太, 高橋浩晃, 堀高峰

    日本測地学会講演会要旨　138th　2022

  2. 三陸沖北部、十勝・根室沖での海底地殻変動観測の開始 ～海域で将来起こりうる巨大地震を調べる～

    富田史章

    JAMSTEC 研究者コラム　2021/03/03

  3. Information column for disaster mitigation (98)

    Fumiaki Tomita

    Public Relations Erimo (Feb. 2019)　(963)　2019/02

  4. 平成 28 年熊本地震に関する緊急情報共有会の開催

    富田史章

    東北大学グローバル安全学トップリーダー育成プログラム 学生自主企画活動報告書　268-281　2017/03

  5. リーディング大学院学生討論会の実施報告

    富田史章, 今野大輔, 柳田泰宏, 松本恵子, 今野明咲香

    東北大学グローバル安全学トップリーダー育成プログラム 学生自主企画活動報告書　12-31　2017/03

  6. 発展途上国における火山災害に 対する建築システムの安全性の検討～インドネシア・ケルート火山を対象とした現地調査～

    今野大輔, 柳田泰宏, 松本恵子, 今野明咲香, 富田史章

    東北大学グローバル安全学トップリーダー育成プログラム 学生自主企画活動報告書　322-381　2016/03

  7. 小・中学生および留学生を対象とする総合的防災学習の新教材の開発とアンケートによる効果測定

    久松明史, 渡邉俊介, 金子亮介, 大柳良介, 石橋信治, 富田史章, 安西瞳

    東北大学グローバル安全学トップリーダー育成プログラム 学生自主企画活動報告書　56-105　2016/03

Show all ︎Show first 5

Presentations 108

  1. Initiation of GNSS-Acoustic seafloor geodetic observation along the Japan trench off Boso

    Fumiaki Tomita, Motoyuki Kido, Kazuo Nakahigashi, Yusaku Ohta, Kanata Endo, Chi-Hsien Tang, Ryota Hino

    JpGU Meeting 2025　2025/05/28

  2. Quantitative comparison of underwater sound speed structures derived from GNSS-Acoustic observations and ocean models

    Kazuki Sawanaga, Fumiaki Tomita

    JpGU Meeting 2025　2025/05/28

  3. Seafloor Crustal Deformation Observations Utilizing Unmanned Surface Vehicles at Plate Subduction zones around the Japanese Islands

    Takeshi Iinuma, Motoyuki Kido, Yusaku Ohta, Tatsuya Fukuda, Fumiaki Tomita, Yusuke Yokota, Ryota Hino, Mikiko Fujita, Takane Hori

    JpGU Meeting 2025　2025/05/28

  4. Postseismic deformation of the 2011 Tohoku earthquake: Insights from GNSS, GNSS-A, and repeating earthquake observations Invited

    Fumiaki Tomita, Tianhaozhe Sun, Takeshi Iinuma, Motoyuki Kido, Yusaku Ohta, Naoki Uchida, Kelin Wang

    JpGU Meeting 2025　2025/05/26

  5. Observed abyssal temperature variability modulated by mesoscale eddies

    Shuya Wang, Yusaku Ohta, Motoyuki Kido, Fumiaki Tomita, Ryota Hino

    JpGU Meeting 2025　2025/05/27

  6. A Thin and Weak Oceanic Lithosphere-Asthenosphere Boundary (LAB) Inferred From Crustal Deformation Following the 2011 Mw=9 Tohoku Earthquake

    Tianhaozhe Sun, Fumiaki Tomita, Takeshi Iinuma, Ryota Hino, Motoyuki Kido, Yusaku Ohta, Jiangheng He, Kelin Wang

    The 2024 AGU Annual Meeting　2024/12/13

  7. Postseismic deformation following the 2011 Tohoku earthquake revealed by onshore geodetic, offshore geodetic, and small repeating earthquake observations

    Fumiaki Tomita, Tianhaozhe Sun, Takeshi Iinuma, Motoyuki Kido, Yusaku Ohta, Naoki Uchida, Ryota Hino, Kelin Wang

    The 2024 AGU Annual Meeting　2024/12/10

  8. Slip deficits off Nemuro inferred from GNSS-A surveys

    Fumiaki Tomita, Yusaku Ohta, Motoyuki Kido, Mako Ohzono, Hiroaki Takahashi, Ryota Hino, Takeshi Iinuma

    142th Meeting of the Geodetic Society of Japan　2024/10/31

  9. Utilization of Unmanned Surface Vehicles in GNSS-Acoustic Observation Using to Detect the Seafloor Crustal Deformation

    Takeshi Iinuma, Motoyuki Kido, Tatsuya Fukuda, Yusaku Ohta, Fumiaki Tomita, Ryota Hino, Hiroaki Takahashi, Takane Hori, Yusuke Yokota

    The 2024 SSJ Fall Meeting　2024/10/22

  10. Postseismic deformation after the 2011 Tohoku earthquake captured by GNSS, GNSS-A, and small repeating earthquakes

    Fumiaki Tomita, Tianhaozhe Sun, Takeshi Iinuma, Motoyuki Kido, Yusaku Ohta, Naoki Uchida, Ryota Hino, Kelin Wang

    2024 SSJ Fall Meeting　2024/10/21

  11. Elucidation of interplate slip behaviors in a subduction zone based on seafloor geodetic observations Invited

    Fumiaki Tomita

    2024 SSJ Fall Meeting　2024/10/21

  12. GNSS-Acoustic Observation Using the Wave Glider to Detect the Seafloor Crustal Deformation (5)

    Takeshi Iinuma, Motoyuki Kido, Tatsuya Fukuda, Yusaku Ohta, Fumiaki Tomita, Ryota Hino, Hiroaki Takahashi, Takane Hori, Daisuke Sato

    JpGU Meeting 2024　2024/05/29

  13. Evaluation of vertical motion off Tohoku considering uncertainty in GNSS-Acoustic positioning

    Fumiaki Tomita, Motoyuki Kido, Takeshi Iinuma, Yusaku Ohta, Ryota Hino

    JpGU Meeting 2024　2024/05/29

  14. Shallow interplate slip deficit inferred from GNSS-Acoustic observations off Nemuro

    Fumiaki Tomita, Yusaku Ohta, Motoyuki Kido, Takeshi Iinuma, Naoki Kurosu, Mako Ohzono, Hiroaki Takahashi, Ryota Hino

    JpGU Meeting 2024　2024/05/31

  15. GNSS-A vertical positioning considering uncertainty of a sound speed profile

    Fumiaki Tomita, Motoyuki Kido

    Symposium for Ocean and Earth 2023　2024/03/01

  16. GNSS-acoustic observations using manned and unmanned sea surface platforms along the Kurile-Japan Trench to grasp the interplate locking state and the postseismic deformation of the 2011 Tohoku-oki earthquake

    Iinuma, T, M. Kido, F. Tomita, T. Fukuda, R. Hino, T. Hori, K. Nakahigashi, H. Takahashi, T. No, Y. Nakamura, M. Ohzono, R. Plata-Martinez, D. Sato

    The 2023 AGU Annual Meeting　2023/12/14

  17. Onboard processing and transmission of realtime GNSS-Acoustic data on a waveglider

    Kido, M, T. Iinuma, T. Fukuda, Y. Ohta, F. Tomita, N. Murai

    The 2023 AGU Annual Meeting　2023/12/14

  18. Development of a new GNSS-acoustic positioning software “SeaGap” and its application

    Tomita, F, M. Kido

    The 2023 AGU Annual Meeting　2023/12/14

  19. Crustal structure in the 17th century Kuril earthquake and its linkage to the occurrence of the large shallow slip

    Azuma, R, S. Kodaira, R. Hino, G. Fujie, K. Obana, F. Tomita, Y. Ohta

    2023 SSJ Fall Meeting　2023/11/01

  20. GNSS-Acoustic seafloor geodetic observations and their results along the Japan-Kuril trench

    Tomita, F, M. Kido, T. Iinuma, Y. Ohta, R. Hino, M. Ohzono, H. Takahashi, R. Plata-Martínez, T. No, K. Nakahigashi, K. Nakamura

    2023 SSJ Fall Meeting　2023/10/31

  21. Future Prospects for Seafloor Crustal Deformation Observation Using GNSS-Acoustic Observations with Wave Gliders

    Iinuma, T, M. Kido, T. Fukuda, Y. Ohta, F. Tomita

    140th Meeting of the Geodetic Society of Japan　2023/10/11

  22. Development of a GNSS-Acoustic positioning method assuming a horizontal gradient underwater sound speed structure with various prior distributions

    Tomita, F

    140th Meeting of the Geodetic Society of Japan　2023/10/11

  23. Array displacement estimation of seafloor crustal deformation observation by the training ship "Shioji Maru" of Tokyo University of Marine Science and Technology considering sound velocity gradient structure

    Yuu Okayama, Kazuo Nakahigashi, Motoyuki Kido, Fumiaki Tomita

    JpGU Meeting 2023　2023/05/24

  24. GNSS-Acoustic seafloor geodetic observations using a Wave Glider off Tohoku and their results

    Fumiaki Tomita, Takeshi Iinuma, Motoyuki Kido, Yusaku Ohta, Tatsuya Fukuda, Ryota Hino

    JpGU Meeting 2023　2023/05/22

  25. New slip deficit rate model and slow earthquakes at the Nankai subduction zone

    Raymundo Omar, Plata Martinez, Takeshi Iinuma, Fumiaki Tomita, Takuya NISHIMURA, Yasuyuki Nakamura, Takane Hori

    JpGU Meeting 2023　2023/05/24

  26. GNSS-Acoustic Observation Using the Wave Glider to Detect the Seafloor Crustal Deformation (4)

    Takeshi Iinuma, Motoyuki Kido, Tatsuya Fukuda, Yusaku Ohta, Fumiaki Tomita, Raymundo Plata Martinez, Ryota Hino, Hiroaki Takahashi, Takane Hori

    JpGU Meeting 2023　2023/05/23

  27. Seismic structural characteristics illuminating a large shallow slip zone in the 17th-century Kuril earthquake

    Ryosuke Azuma, Shuichi Kodaira, Ryota Hino, Gou Fujie, Koichiro Obana, Fumiaki Tomita, Yusaku Ohta

    JpGU Meeting 2023　2023/05/24

  28. Development of a new software for GNSS-acoustic positioning (SeaGap)

    Fumiaki Tomita

    JpGU Meeting 2023　2023/05/23

  29. 「かいめい」による北海道南東沖千島海溝周辺での地震探査

    野 徹雄, 小平 秀一, 藤江 剛, 尾鼻 浩一郎, 中村 恭之, 新井 隆太, 白石 和也, 三浦 亮, 瀧澤 薫, 山口 寛登, 藤本 萌, 中西 正男, 海宝 由佳, 孫 岳, 于 凡, 朴 進午, 小林 稜弥, 五十嵐 智秋, 木戸 元之, 富田 史章, 飯沼 卓史

    海と地球のシンポジウム2022　2023/03/16

  30. Slip deficit rate and slow earthquake distribution at the Nankai Trough

    R. Plata-Martinez, T. Iinuma, F. Tomita, T. Nishimura, R. Agata, T. Hori

    2022 AGU Fall Meeting　2022/12/15

  31. Near-Trench Postseismic Subsidence Following the 2011 Tohoku-oki Earthquake Revealed by GNSS-Acoustic Observations

    F. Tomita, M. Kido, C. Honsho, T. Iinuma, Y. Ohta, R. Hino, T. Sun, H. Luo, K. Wang

    2022 AGU Fall Meeting　2022/12/16

  32. Recent GNSS-Acoustic seafloor geodetic observations off Tohoku and their results

    Fumiaki Tomita, Motoyuki Kido, Takeshi Iinuma, Yusaku Ohta, Chie Honsho, Ryota Hino, Tetsuo No, Kazuo Nakahigashi

    2022 SSJ Fall Meeting　2022/10/24

  33. Seafloor Geodetic Observations along the Kuril Trench off Nemuro

    Fumiaki Tomita, Motoyuki Kido, Yusaku Ohta, Ryota Hino, Takeshi Iinuma, Chie Honsho, Mako Ohzono, Hiroaki Takahashi

    2022 SSJ Fall Meeting　2022/10/24

  34. Attitudes of a Wave Glider under various sea conditions

    Motoyuki Kido, Takeshi Iinuma, Tatsuya Fukuda, Yusaku Ohta, Fumiaki Tomita

    138th Meeting of the Geodetic Society of Japan　2022/10/05

  35. GNSS-Acoustic Observation Using the Wave Glider to Detect the Seafloor Crustal Deformation (3)

    Takeshi Iinuma, Motoyuki Kido, Tatsuya Fukuda, Yusaku Ohta, Fumiaki Tomita, Keisuke Ariyoshi, Kei Nagano, Raymundo Plata-Martinez, Ryota Hino, Hiroaki Takahashi, Takane Hori

    138th Meeting of the Geodetic Society of Japan　2022/10/05

  36. Slip deficit and its correlation with slow and fast earthquakes at the Nankai subduction zone

    R. Plata-Martinez, T. Iinuma, F. Tomita, T. Nishimura, R. Agata, T. Hori

    International Joint Workshop on Slow-to-Fast Earthquakes 2022　2022/09/14

  37. Detection of aseismic slip events along the plate interface after the 2011 Tohoku-oki earthquake inferred from geodetic data

    Fumiaki Tomita

    JpGU Meeting 2022　2022/06/03

  38. GNSS-Acoustic seafloor geodetic observations using a Wave Glider off Tohoku

    Fumiaki Tomita, Takeshi Iinuma, Motoyuki Kido, Yusaku Ohta, Chie Honsho, Tatsuya Fukuda

    JpGU Meeting 2022　2022/05/27

  39. Impact of employing a waveglider on GNSS-Acoustic survey along the Japan trench

    Motoyuki Kido, Chie Honsho, Fumiaki Tomita, Yusaku Ohta, Ryota Hino, Takeshi Iinuma

    EGU General Assembly 2022　2022/05/24

  40. GNSS-Acoustic observation using the Wave Glider to detect the seafloor crustal deformation off the Pacific coast of Northeastern Japan

    Takeshi Iinuma, Motoyuki Kido, Tatsuya Fukuda, Fumiaki Tomita, Yusaku Ohta, Chie Honsho, Ryota Hino

    2021 AGU Fall Meeting　2021/12/15

  41. Development of a GNSS-Acoustic positioning method using a MCMC technique

    Fumiaki Tomita, Motoyuki Kido

    136th Meeting of the Geodetic Society of Japan　2021/11/17

  42. GNSS-Acoustic observations using a Wave Glider and the recent seafloor crustal deformation off Tohoku

    Fumiaki Tomita, Takeshi Iinuma, Motoyuki Kido, Chie Honsho, Yusaku Ohta, Tatsuya Fukuda

    2021 SSJ Fall Meeting　2021/10/15

  43. GNSS-Acoustic observations using a Wave Glider and their results

    Tomita, F, M. Kido, Y. Ohta, T. Iinuma, C. Honsho, T. Fukuda, T. Hori

    JpGU Meeting 2021　2021/06/05

  44. Vertical seafloor movement after the 2011 Tohoku earthquake and remarkable uplift near the trench axis off Sanriku

    Honsho, C, M. Kido, F. Tomita, R. Hino

    JpGU Meeting 2021　2021/06

  45. nterpretation for variation in the incoming Pacific Plate structure around the Kuril Trench axial region by an OBS/MCS seismic survey

    Azuma, R, S. Kodaira, R. Hino, G. Fujie, K. Obana, F. Tomita, Y. Ohta

    JpGU Meeting 2021　2021/06

  46. Semi-realtime transmission of GNSS-A data using a Wave Glider

    Kido, M, T. Fukuda, Y. Ohta, F. Tomita, C. Honsho, T. Iinuma

    JpGU Meeting 2021　2021/06

  47. Urgent observation of seafloor crustal movement and installation of seafloor seismographs in preparation for future earthquakes off the east coast of Aomori Prefecture

    Hori, T, T. Iinuma, F. Tomita, M. Kido, C. Honsho, R. Azuma, C. Tang, Y. Ohta, R. Nakata, R. Hino, M. Shinohara, S. Kodaira

    JpGU Meeting 2021　2021/06

  48. Improvement of spatial resolution and evaluation of uncertainty for the coseismic slip distribution of the 2011 Tohoku-oki Earthquake

    Tomita, F, T. Iinuma, M. Kido, R. Hino, Y. Ohta, R. Agata, T. Hori, N. Uchida

    JpGU Meeting 2021　2021/06

  49. Imaging of fault-slip distributions using a trans-dimensional geodetic slip inversion approach

    Tomita, F, T. Iinuma, R. Agata, T. Hori

    2020 AGU Fall Meeting　2020/12

  50. Crustal structure of the incoming Pacific Plate off Hokkaido, the southern Kuril Trench subduction zone, by an active-source seismic survey using dense linear OBS array

    Azuma, R, S. Kodaira, R. Hino, G. Fujie, K. Obana, F. Tomita, Y. Ohta

    2020 AGU Fall Meeting　2020/12

  51. GNSS-Acoustic Observation Using the Wave Glider to Detect the Seafloor Crustal Deformation (2)

    Iinuma, T, M. Kido, T. Fukuda, Y. Ohta, F. Tomita, R. Hino

    2020 SSJ Fall Meeting　2020/10/31

  52. Crustal structure in the Kuril Trench subduction zone off Hokkaido, Japan, by a dense linear OBS-array seismic survey

    Azuma, R, S. Kodaira, R. Hino, G. Fujie, K. Obana, F. Tomita, Y. Ohta

    2020 SSJ Fall Meeting　2020/10/30

  53. Estimation of coupling slip distributions in a subduction zone by a trans-dimensional inversion approach

    Tomita, F, T. Iinuma, R. Agata, T. Hori

    2020 SSJ Fall Meeting　2020/10/31

  54. Onset of GNSSAcoustic observation for horizontal and vertical movements off Nemuro region using a triangular PXP array with an optional centered-PXP

    Kimura, Y, M. Kido, Y. Ohta, C. Honsho, F. Tomita

    134th Meeting of the Geodetic Society of Japan　2020/10/22

  55. Detection of seafloor crustal deformation by GNSS-Acoustic measurement using a Wave Glider - preliminary results of a trial observation for long-term operation

    Tomita, F, M. Kido, Y. Ohta, T. Iinuma, T. Fukuda, C. Honsho

    134th Meeting of the Geodetic Society of Japan　2020/10/22

  56. Estimation on fault-slip distributions without smoothing constraints by Reversible-jump MCMC

    Tomita, F, T. Iinuma, R. Agata, T. Hori

    JpGU-AGU Joint Meeting 2020　2020/07

  57. Active-source seismic study with a dense linear OBS array off Nemuro, the southern Kuril subduction zone

    Azuma, R, S. Kodaira, R. Hino, G. Fujie, K. Obana, F. Tomita, Y. Ohta

    JpGU-AGU Joint Meeting 2020　2020/07

  58. Launch of GNSS-Acoustic observation for horizontal and vertical movements off Nemuro using a triangular PXP array with an optional centered-PXP

    Kimura, Y, M. Kido, Y. Ohta, C. Honsho, F. Tomita

    JpGU-AGU Joint Meeting 2020　2020/07

  59. Improvements in GNSS-Acoustic analysis for the enhancement of positioning accuracy: application of phase-only correlation to travel time determination and positioning analysis considering the effect of earth tide

    Honsho, C, M. Kido, F. Tomita, Y. Ohta, H. Ichikawa, T. Ohashi, T. Kawakami

    JpGU-AGU Joint Meeting 2020　2020/07

  60. GNSS-Acoustic Observation Using the Wave Glider to Detect the Seafloor Crustal Deformation Associated with the Temporal Change in the Interplate Locking State

    Iinuma, T, M. Kido, Y. Ohta, T. Fukuda, F. Tomita, R. Hino, I. Ueki

    2019 AGU Fall Meeting　2019/12/13

  61. Estimation on co- & post-seismic slip distributions through viscoelastic inversion using Reversible-jump MCMC

    Tomita, F, T. Iinuma, R. Agata, T. Hori

    2019 AGU Fall Meeting　2019/12/13

  62. Detection of seafloor crustal deformation by GNSS-Acoustic measurement using a Wave Glider

    Tomita, F, M. Kido, Y. Ohta, T. Iinuma, T. Fukuda

    132th Meeting of the Geodetic Society of Japan　2019/10/30

  63. Estimation on fault slip distributions through viscoelastic inversion using Reversible-jump MCMC

    Tomita, F, T. Iinuma, R. Agata, T. Hori

    2019 SSJ Fall Meeting　2019/09/16

  64. Construction of the sea-floor geodesy network in Nemuro-Oki, the southwestern part of the Kuril Trench

    Ohta, Y, M. Kido, R. Azuma, M. Sato, S. Suzuki, R. Yamamoto, H. Takahashi, Y. Kimura, H. Otsuka, C. Honsho, R. Hino, M. Ohzono, K. Okada, Y. Aota, H. Takahashi, S. Masanao, F. Tomita, T. Kanamatsu, K. Hsiung, T. Iinuma

    2019 SSJ Fall Meeting　2019/09/16

  65. Preliminary Report of the GNSS-Acoustic Observation Using the Wave Glider to Detect the Seafloor Crustal Deformation

    Iinuma, T, M. Kido, Y. Ohta, T. Fukuda, F. Tomita, I. Ueki

    2019 SSJ Fall Meeting　2019/09/16

  66. Simple estimation of interplate coupling in the Kushiro-oki and the Nemuro-oki regions, eastern Hokkaido in Japan from onshore GNSS data

    Aota, H, M. Ohzono, F. Tomita, H. Takahashi

    JpGU Meeting 2019　2019/05/26

  67. Offshore Postseismic Deformation of the 2011 Tohoku Earthquake Revisited: Application of an Improved GPS-Acoustic Positioning Method Considering Sloping Sound Speed Structure

    Honsho, C, M. Kido, F. Tomita, N. Uchida

    JpGU Meeting 2019　2019/05/26

  68. Development of a kinematic GNSS-A positioning method using the extended Kalman-filter to detect precise vertical displacement

    Tomita, F, M. Kido, C. Honsho, R. Matsui

    JpGU Meeting 2019　2019/05/26

  69. Recent progresses in GNSS-Acoustic positioning technique and results in the off-Tohoku region, Japan International-presentation Invited

    Tomita, F, C. Honsho, M. Kido

    AGU Fall Meeting 2018　2018/12

  70. Episodic slow slip after the 2011 Tohoku-oki earthquake: Detection from repeating earthquakes, very low frequency earthquakes, and seafloor geodetic observations

    Uchida, N, C. Honsho, F. Tomita, T. Matsuzawa, R. Bürgmann

    SSJ Fall Meeting 2018　2018/10

  71. Development of GNSS-Acoustic positioning method based on State-Space Model

    Tomita, F, M. Kido, R. Matsui

    130th Meeting of the Geodetic Society of Japan　2018/10

  72. Seafloor geodetic observations to reveal co- and post-seismic slip distributions of the 2011 Tohoku-oki earthquake International-presentation

    Tomita, F, Y. Ohta, T. Iinuma, R. Hino, M. Kido, N. Uchida

    OCEANS’ 18 MTS　2018/05/30

  73. Extension of postseismic geodetic observations constrains on coseismic slip distribution through viscoelastic relaxation

    Tomita, F, Y. Ohta, T. Iinuma, R. Hino, M. Kido, N. Uchida

    Japan Geoscience Union Meeting 2018　2018/05

  74. Spatially non-linear property of sound speed structure in GPS-acoustic measurement

    Matsui, R, M. Kido, C. Honsho, F. Tomita

    Japan Geoscience Union Meeting 2018　2018/05

  75. Array positioning analysis of GPS-Acoustic observation data considering lateral gradient of the sound speed in seawater

    Honsho, C, M. Kido, F. Tomita

    Japan Geoscience Union Meeting 2018　2018/05

  76. Detecting gradient of sound speed in ocean by GPS-Acoustic technique

    Matsui, R, M. Kido, C. Honsho, F. Tomita

    128th Meeting of the Geodetic Society of Japan　2017/10

  77. Simultaneous estimation on co- and post-seismic slip distribution using viscoelastic Green’s function

    Tomita, F, Y. Ohta, T. Iinuma, M. Kido, R. Hino

    128th Meeting of the Geodetic Society of Japan　2017/10

  78. Simultaneous estimation on co- and post-seismic slip distribution of the 2011 Tohoku-oki earthquake using viscoelastic Green’s function

    Tomita, F, Y. Ohta, R. Hino, M. Kido, T. Iinuma

    SSJ Fall Meeting 2017　2017/10

  79. Spatio-Temporal Variation of the Postseismic Deformation Associated with the 2011 Tohoku Earthquake (M9.0) Based on Terrestrial and Seafloor Observations International-presentation

    Iinuma, T, Y. Ohta, S. Miura, J. Muto, F. Tomita, M. Kido, R. Hino

    AOGS 14th Annual Meeting　2017/08

  80. Postseismic deformation of the 2011 Tohoku Earthquake measured by GPS/Acoustic observations International-presentation

    Tomita, F, M. Kido, Y. Ohta, T. Iinuma, R. Hino

    IAG-IASPEI 2017　2017/08

  81. Detection of offshore vertical displacements after the 2011 Tohoku-oki Earthquake using GPS/A observations International-presentation

    Tomita, F, C. Honsho, M. Kido

    IAG-IASPEI 2017　2017/08

  82. Spatio-temporal variation of the postseismic deformation of the 2011 Tohoku Earthquake based on terrestrial and seafloor observations International-presentation

    Iinuma, T, Y. Ohta, S. Miura, J. Muto, F. Tomita, M. Kido, R. Hino

    JpGU-AGU Joint Meeting 2017　2017/05

  83. Comparison between temporal variation of sound velocity derived from GPS/acoustic and CTD measurements International-presentation

    Matsui, R, M. Kido, C. Honsho, F. Tomita

    JpGU-AGU Joint Meeting 2017　2017/05

  84. Evaluation of the sound speed equations for seawater proposed by Chen-and-Millero and Del-Grosso using GPS/Acoustic observation data International-presentation Invited

    Honsho, C, M. Kido, F. Tomita

    JpGU-AGU Joint Meeting 2017　2017/05

  85. Detection of offshore vertical displacements after the 2011 Tohoku-oki Earthquake from GPS-A observations

    Tomita, F, C. Honsho, M. Kido

    JpGU-AGU Joint Meeting 2017　2017/05

  86. Postseismic deformation associated with the 2011 Tohoku Earthquake deduced by means of GPS/Acoustic surveys International-presentation

    Tomita, F, M. Kido, Y. Ohta, T. Iinuma, R. Hino

    EGU General Assembly 2017　2017/04

  87. Spatiotemporal variation in the postseismic deformation of the 2011 Tohoku-oki earthquake revealed by seafloor geodetic observations International-presentation

    Tomita, F, M. Kido, Y. Ohta, R. Hino, T. Iinuma

    AGU Fall Meeting 2016　2016/12

  88. Measuring Relative Motions Across a Fault Using Seafloor Transponders Installed at Close Range to Each Other Based on Differential GPS/Acoustic Technique International-presentation

    Kido, M, J. Ashi, T. Tsuji, F. Tomita

    AGU Fall Meeting 2016　2016/12

  89. GPS/A観測によって捉えた2011年東北沖地震に伴う余効変動の時空間変化

    富田史章, 木戸元之, 太田雄策, 日野亮太, 飯沼卓史

    日本地震学会2016年度秋季大会　2016/10

  90. Effects of an initial underwater sound speed profile in GPS-Acoustic measurements

    Tomita, F, M. Kido, C. Honsho

    126th Meeting of the Geodetic Society of Japan　2016/10

  91. Postseismic Deformation Associated with the 2011 Tohoku-Oki Earthquake (M9.0) Based on 5 Years of Seafloor and Terrestrial Geodetic Observation International-presentation Invited

    Iinuma, T, F. Tomita, M. Kido, Y. Ohta, R. Hino, Y. Osada

    AOGS 13th Annual Meeting　2016/08

  92. Detecting a relative motion across the Japan Trench using precise acoustic ranging

    Yamamoto, R, R. Hino, M. Kido, Y. Ohta, T. Kubota, F. Tomita, K. Ohta, Y. Osada

    Japan Geoscience Union Meeting 2016　2016/05

  93. Detecting localized seafloor deformation using traveltime difference of acoustic signals of transponders nearby -Observation in the Japan Trench-

    Kido, M, J. Ashi, T. Tsuji, F. Tomita

    Japan Geoscience Union Meeting 2016　2016/05

  94. Spatial characteristics of postseismic deformation following the 2011 Tohoku-oki earthquake inferred from repeated GPS/Acoustic observations

    Tomita, F, M. Kido, Y. Ohta, R. Hino, T. Iinuma, Y. Osada

    Japan Geoscience Union Meeting 2016　2016/05

  95. Spatial characteristics of postseismic deformation of the 2011 Tohoku-oki earthquake revealed by GPS/Acoustic observations

    Tomita, F, M. Kido, Y. Ohta, R. Hino, T. Iinuma, Y. Osada

    Symposium on Subduction zone earthquakes in Nankai Trough & Japan Trench　2016/02

  96. Postseismic deformation of the 2011 Tohoku-Oki earthquake revealed by repeated GPS/Acoustic observations International-presentation

    Tomita, F, M. Kido, Y. Ohta, R. Hino, Y. Osada

    AGU Fall Meeting 2015　2015/12

  97. Postseismic deformation following the 2011 Tohoku-oki earthquake measured by GPS/A seafloor geodetic observation

    Tomita, F, Y. Osada, Y. Ohta, R. Hino, M. Kido, T. Iinuma

    SSJ Fall Meeting 2015　2015/10

  98. Direct-path acoustic ranging across the Japan trench: Efforts to realize long-term, long-baseline, and multi-station observation

    Hino, R, R. Yamamoto, Y. Osada, M. Kido, S. Suzuki, Y. Ohta, T. Kubota, F. Tomita

    124th Meeting of the Geodetic Society of Japan　2015/10

  99. 簡易アンケートによる小・中学生の防災意識の調査と「減災アクションカードゲーム」の効果測定

    大柳良介, 久松明史, 渡邉俊介, 石橋信治, 安西瞳, 金子良介, 富田史章, 山田修司, 久利美和

    日本災害情報学会第17回学会大会　2015/10

  100. Efficient observations for broad seafloor crustal deformation along the Japan trench

    Kido, M, F. Tomita

    The 25th Ocean Engineering Symposium　2015/08

  101. GPS/A海底測地観測により捉えた2011年東北地方太平洋沖地震の余効変動

    富田史章

    JDASH（深海調査で迫るプレート境界浅部すべりの謎〜その過去・現在）プロジェクト研究集会　2015/06

  102. Postseismic deformation following the 2011 Tohoku-oki earthquake measured by seafloor geodetic observation

    Tomita, F, M. Kido, Y. Osada, R. Hino, Y. Ohta, T. Iinuma, R. Azuma, I. Wada, S. Miura

    JpGU Meeting 2015　2015/05

  103. Fast Displacement Rate of the Subducting Pacific Plate After the 2011 Tohoku-oki Earthquake Measured by GPS/Acoustic Surveys International-presentation

    Tomita, F, M. Kido, Y. Osada, R. Hino, T. Iinuma, Y. Ohta

    AGU Fall Meeting 2014　2014/12

  104. Detection of high displacement rate on the Pacific plate after the 2011 Tohoku-oki earthquake inferred from GPS/Acoustic observations

    Tomita, F, M. Kido, Y. Osada, T. Iinuma, R. Hino, Y. Ohta

    122th Meeting of the Geodetic Society of Japan　2014/11

  105. Postseismic Seafloor Deformation Associated with the2011 Tohoku-oki Earthquake Revealed by Repeated GPS/Acoustic Observations International-presentation

    Tomita, F, M. Kido, Y. Osada, R. Azuma, R. Hino, H. Fujimoto, T. Iinuma, Y. Ohta, I. Wada

    GENAH2014　2014/07

  106. The postseismic deformation of the 2011 Tohoku-oki Earthquake observed by repeated GPS/Acoustic surveys International-presentation

    Tomita, F, M. Kido, Y. Osada, H. Fujimoto, R. Hino, R. Azuma, T. Iinuma, Y. Ohta, I. Wada

    AOGS 11th Annual Meeting　2014/07

  107. Detection of post-seismic movement after Tohoku-oki Earthquake using GPS/Acoustic technique

    Tomita, F, M. Kido, Y. Osada, R. Azuma, H. Fujimoto, R. Hino, T. Iinuma, Y. Ohta, I. Wada

    JpGU Meeting 2014　2014/04

  108. A trial for detection of the subducting rate of the Pacific plate using GPS-Acoustic observations

    Tomita, F, M. Kido, Y. Osada, H. Fujimoto, R. Hino, T. Iinuma, R. Azuma, Y. Ohta

    120th Meeting of the Geodetic Society of Japan　2013/10

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Research Projects 4

  1. 空間解像度に基づく小断層配置最適化による断層すべり推定手法の開発

    富田 史章

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 若手研究

    Institution: 東北大学

    2024/04 - 2028/03

  2. Waveglider-based GNSS-acoustic survey utilized oceanographic model

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2024/04/01 - 2027/03/31

  3. 2011年東北沖地震に伴う断層すべりの時空間発展の高解像度推定

    富田 史章

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 若手研究

    Category: 若手研究

    Institution: 国立研究開発法人海洋研究開発機構

    2020/04/01 - 2023/03/31

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    沈み込み帯のプレート境界における巨大地震サイクルに伴う断層すべりの時空間発展を高い解像度で推定することは，プレート境界における力学的特性を把握する上で極めて重要である．本研究では，巨大地震後の地殻変動観測データが過渡的な現象である粘弾性緩和を介して過去の断層すべりに関する情報を有していることに着目し，2011年東北沖地震における 地震間・地震時・地震後の地殻変動観測データを統合して解析（粘弾性インバージョン）することで，高解像度の断層すべりの時空間発展の推定に取り組む．本年度では，昨年度に大枠を開発したReversible-jump MCMC法による断層すべり推定手法を論文として取りまとめ，粘弾性インバージョンに適用できる状態に整えた．論文として取りまとめた内容では模擬データ，及び2011年東北沖地震時変位の実データに対してに本手法の適用を行った．これらに加え，南海トラフにおける固着分布推定にReversible-jump MCMC法を活用し，地震間の実データに対しても問題なく本手法を適用可能であることを確かめた．更に，地震サイクルにおける断層すべりの時空間発展を推定する際に活用する測地観測データの整理を行った．具体的には，陸上GNSSデータ，及び海域のGNSS音響観測データを用いて，余震・GNSS共通誤差・周期変動等の系統的な誤差要因を取り除く手法開発を行い，実際の適用に資する精緻なデータセットを揃えた．一方で，本研究における推定において重要となる東北沖における3次元粘弾体を考慮した変形を表現するグリーン関数については，試行錯誤を重ねており，現在その精査を行っている．

  4. 海底測地観測の高精度化を通した東北沖地震に伴う余効変動プロセスの解明

    富田 史章

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 特別研究員奨励費

    Category: 特別研究員奨励費

    2017/04/26 - 2019/03/31

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    本研究は，（１）GPS音響結合方式による海底地殻変動観測（以後，GPS-A観測）データ解析の高精度化を図ることで，2011年東北地方太平洋沖地震（以後，東北沖地震）後の詳細な海底地殻変動場を明らかにし，（２）（１）の結果を用いて東北沖地震に伴う地震後地殻変動（余効変動）のモデル化を行う，ことで構成される． （１）GPS-A観測データ解析においては，海中音速の傾斜構造を取り入れた傾斜パラメータと海底局位置（海底での変位）の同時推定を試みた．同時推定では，カルマンフィルタを導入することで海中音速構造の詳細な時空間変化を捉えることを試みた．しかし，海底局位置と傾斜パラメータ間のトレードオフが顕著であり，単一音響測距ごとでの精密測位は困難であることがわかった．一方で，観測時間内で普遍な海中音速の傾斜構造については，一部の観測データにおいては除去できることが判明し，測位精度の改善に成功した． （２）東北沖地震に伴う余効変動のモデル化では，（１）によって改善された測位結果を得るのに時間を要したため，従来手法によるGPS-A観測成果を用いて解析を実施した．GPS-A観測成果と，余効変動要因の一つである粘弾性緩和に関する先行研究のモデルを比較したところ，粘弾性緩和の発生要因である地震時すべり分布モデルの不確定性が余効変動のモデル化に与える影響が大きいことがわかった．そこで，粘弾性緩和の影響をグリーン関数として取り入れること（粘弾性グリーン関数）で，地震時すべり分布と地震後すべり分布の同時推定を行った．その結果，東北沖地震後の海底地殻変動データを加えることで，地震時・地震後ともにこれまでより高空間分解能でのすべり分布を得ることに成功した．このことは，地震が発生した後であっても，海底地殻変動観測などの観測網を充実させることで，地震後の測地観測から地震時の変動を拘束できることを示している．

Teaching Experience 1

  1. Geophysical Experiments Ⅰ & Ⅱ　Tohoku University

Media Coverage 9

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