Researcher basic information

• Doctor of Engineering, The University of Tokyo

• https://researchmap.jp/yamanakay?lang=en

• https://orcid.org/0000-0002-7260-7034
• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201801003295116924

• 60815108

• https://orcid.org/0000-0002-7260-7034

• 201801003295116924

• Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention), Disaster prevention engineering
• Natural Science, Solid earth sciences
• Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention), Hydroengineering

• Bachelor's degree program, School of Science
• Master's degree program, Graduate School of Science
• Doctoral (PhD) degree program, Graduate School of Science

Research activity information

• May 2026, Geophysical Research Letters, Top viewed article 2025
  Yusuke Yamanaka;Yoshinao Matsuba;Takenori Shimozono;Yoshimitsu Tajima, Nearshore Propagation and Amplification of the Tsunami Following the 2024 Noto Peninsula Earthquake, Japan; the top 10% of most-viewed papers published by the journal in 2024.
• Mar. 2025, Earth, Planets and Space, Excellent Reviewers 2024
  Yusuke Yamanaka
• Feb. 2023, Earth, Planets and Space, Highlighted Papers 2022
  Yuichiro Tanioka;Yusuke Yamanaka;Tatsuya Nakagaki, Characteristics of the deep sea tsunami excited offshore Japan due to the air wave from the 2022 Tonga eruption, Official journal
• Nov. 2022, Coastal Engineering Committee, JSCE, Coastal Engineering Journal Reviewer Award 2021
  Yusuke Yamanaka, Official journal

• Spatiotemporal Distribution of Coseismic Slip During the 2025 Kamchatka Earthquake Inferred from Tsunami Waveform Data
  Tatok Yatimantoro; Yusuke Yamanaka; Yuichiro Tanioka
  Bulletin of the Seismological Society of America, Seismological Society of America (SSA), 08 Sep. 2026, [Peer-reviewed], [International Magazine]
  English, Scientific journal, ABSTRACT
  
  On 29 July 2025 (UTC), an earthquake with a moment magnitude of approximately 8.8 occurred along the plate interface of the Kamchatka subduction zone and generated a trans-Pacific tsunami. Using tsunami waveform data recorded at offshore stations, we conducted tsunami waveform inversion based on a multiple time-window approach to investigate the spatiotemporal distribution of coseismic slips during the earthquake. The inversion results suggest temporally distributed slip evolution, with the largest slip occurring approximately 180–225 s after the earthquake occurrence. The slip distribution indicates that the dominant asperities were located primarily in the shallow-to-intermediate portions of the fault plane, whereas the largest slip was estimated to be in the deeper region at approximately 12 m. Resolution tests of our inversion analysis suggest that slips in the shallow-to-intermediate portions of the fault plane were relatively well constrained, whereas those in the deeper region were less well resolved. This reduced resolution likely reflects the lower sensitivity of far-field tsunami observations to deep fault slip, together with limitations in the azimuthal distribution of offshore stations. The total seismic moment derived from the developed source model was 1.44×1022  N·m, corresponding to a moment magnitude of 8.7. The spatiotemporal characteristics of slips in our source model were comparable with source models developed by previous studies using other observational data.
• Historical tsunamigenic earthquakes in the Sea of Japan: case study of an event inferred from tsunami deposits in the Hokkaido region, Japan
  Yuto Tsutsui; Yusuke Yamanaka
  Coastal Engineering Journal, 1, 18, Informa UK Limited, 27 May 2026, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
  English, Scientific journal
• Comparison of the tsunamis following the 2025 and 1952 Kamchatka Earthquakes, Russia: field observations along the Japanese coast
  Yusuke Yamanaka; Yota Atobe; Yuto Tsutsui; Kazumi Okada; Hiroaki Takahashi; Yuichiro Tanioka
  Earth, Planets and Space, 11 Dec. 2025, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Tsunami penetration along a river: insights from the tsunami following the 2024 Noto Peninsula Earthquake, Japan
  Yusuke Yamanaka; Yoshinao Matsuba; Takenori Shimozono; Yoshimitsu Tajima
  Coastal Engineering Journal, 02 Oct. 2025, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Investigation of a static source model for non-seismic tsunamis using waveform inversion: A case study of the 2018 Anak Krakatau event
  Tatok Yatimantoro; Yusuke Yamanaka; Aditya Riadi Gusman; Yuichiro Tanioka; Rinda Nita Ratnasari; Dwikorita Karnawati
  Geophysical Journal International, Oxford University Press (OUP), 29 Jan. 2025, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal, Summary
  
  This study investigates the effectiveness of inversion methods using tsunami waveforms to analyse volcanic tsunami sources, which are a type of non-seismic tsunami source. We focused on the 2018 Anak Krakatau tsunami triggered by a volcanic eruption. This study developed a static initial sea surface displacement model based on tsunami waveform inversion with data recorded at tide gauge stations using a Gaussian-shaped sea surface displacement for the unit source. A key characteristic of our model is that all initial velocity components of the tsunami were zero. We tested 12 scenarios for accuracy to determine the most plausible sea surface displacement. The optimal displacement model reasonably reproduced the observed tsunami waveforms. The calculated water volume at the initial sea surface displacement was reasonably consistent with the total collapse volume of the Anak Krakatau eruption by magnitude. These findings suggest that our approach to developing a static source model can effectively apply to non-seismic tsunami events. Although this approach offers simplified tsunami source modeling for tsunami estimation during volcanic eruptions with complex source dynamics, further validation is required for its application to other non-seismic tsunami events.
• Swash Zone Response to the Tsunami Triggered by the 2024 Noto Peninsula Earthquake
  Yoshinao Matsuba; Yoshimitsu Tajima; Takenori Shimozono; Yusuke Yamanaka
  Journal of Geophysical Research: Earth Surface, Jan. 2025, [Peer-reviewed], [Last author], [International Magazine]
  English, Scientific journal
• A MACRO-ANALYSIS OF SEAWALL EFFECTIVENESS IN SMALL COASTAL AREAS
  Sho KAWASE; Takenori SHIMOZONO; Yusuke YAMANAKA
  Japanese Journal of JSCE, 80, 17, n/a, n/a, Japan Society of Civil Engineers, Nov. 2024, [Peer-reviewed], [Last author], [Domestic magazines]
  Scientific journal
• Nearshore Propagation and Amplification of the Tsunami Following the 2024 Noto Peninsula Earthquake, Japan
  Y. Yamanaka; Y. Matsuba; T. Shimozono; Y. Tajima
  Geophysical Research Letters, 51, 19, American Geophysical Union (AGU), 05 Oct. 2024, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal, Abstract
  
  On 1 January 2024, a massive earthquake struck the Noto Peninsula in Japan, and the resulting tsunami significantly damaged the nearby coasts. This study focuses on Iida Bay, located on the peninsula that suffered severe coastal damage. We observed a tsunami waveform in Iida Bay from video analysis owing to the lack of instrument data. This, combined with the waveform observed outside the bay, was used to correct the initial sea‐surface displacements produced by a prior source model. We successfully reproduced the observed waveforms with corrected displacements and investigated how the tsunami propagated and amplified in the bay. Alongshore wave propagation and superposition were identified as crucial factors in this tsunami event.
• Estimation of tsunami characteristics under rough wind waves in the 2024 Noto Peninsula Earthquake
  Yoshimitsu Tajima; Yoshinao Matsuba; Yusuke Yamanaka; Takenori Shimozono; Fuminori Kato
  Coastal Engineering Journal, 1, 15, Informa UK Limited, 31 Jul. 2024, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• Assessment of Tsunami Evacuation Plan in Small Declining Cities: Study Case of Tosashimizu, Japan
  Auriane Lauren; Hiroyuki Hashimoto; Yuki Ishikawa; Aiko Kondo; Takeshi Miwa; Haruka Yamada; Yusuke Yamanaka; Yoshimitsu Tajima
  Proceedings of the 11th International Conference on Asian and Pacific Coasts, 1059, 1067, Jun. 2024, [Peer-reviewed], [International Magazine]
  English, International conference proceedings
• Tsunami waveform inversion using Green’s functions with advection effects: application to the 2003 Tokachi–Oki earthquake
  Yusuke Yamanaka; Yuichiro Tanioka
  Earth, Planets and Space, 76, 71, 1, 14, 10 May 2024, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  Scientific journal
• Real-time tsunami forecasting system with nonlinear effects using Green’s functions: application to near-shore tsunami behavior in complex bay topography
  Yusuke Yamanaka; Kana Hashimoto; Yoshimitsu Tajima
  Coastal Engineering Journal, 1, 14, Informa UK Limited, 14 Nov. 2023, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Recent progress in research on source processes of great earthquakes using tsunami data
  Yuichiro Tanioka; Yusuke Yamanaka
  Progress in Earth and Planetary Science, 10, 1, Springer Science and Business Media LLC, 08 Oct. 2023, [Peer-reviewed], [Invited], [International Magazine]
  English, Scientific journal, Abstract
  
  This paper provides an overview of inverse studies that estimate earthquake source processes using tsunami-related data. Methods and techniques developed with those data associated with the 2004 Sumatra and 2011 Tohoku-oki earthquakes were reviewed. These events significantly impacted subsequent studies that focused on great historical earthquakes. Thus, recent advancements from studies on great historical earthquakes (M > 8) using old tsunami data, including documents and non-digital tsunami waveforms, have been reviewed. Another key earthquake was the 1700 Cascadia earthquake, and its source process was revealed using geological tsunami deposit data, which have led to a recent surge in prehistorical earthquake studies using tsunami deposit data. Considering this, the advancements in prehistorical earthquake studies have been reviewed. Finally, expected advancements in earthquake source process studies using tsunami-related data in the near future have been discussed.
• Re-Estimating a Source Model for the 1923 Kanto Earthquake by Joint Inversion of Tsunami Waveforms and Coseismic Deformation Data
  Yumi Nakadai; Yuichiro Tanioka; Yusuke Yamanaka; Tatsuya Nakagaki
  Bulletin of the Seismological Society of America, 01 Oct. 2023, [Peer-reviewed]
  English, Scientific journal
• Development of early warning system for tsunamis accompanied by collapse of Anak Krakatau volcano, Indonesia
  Rinda Nita Ratnasari; Yuichiro Tanioka; Yusuke Yamanaka; Iyan E. Mulia
  Frontiers in Earth Science, 11, Frontiers Media SA, 06 Sep. 2023, [Peer-reviewed], [International Magazine]
  Scientific journal, Present tsunami warning systems have been specialized for earthquake-generated tsunamis, but rapidly evaluating the tsunamis caused by volcanic eruptions and/or volcanic sector collapses remains a challenge. In this study, we applied a numerical model to the 2018 Anak Krakatau tsunami event, which was generated by the sector collapse, investigated a tsunami prediction skill by the model, and developed a real-time forecasting method based on a pre-computed database for future tsunamis accompanied by such eruption of Anak Krakatau. The database stores spatiotemporal changes in water surface level and flux, which are simulated under various collapse scenarios, for confined areas in the vicinity of potential source. The areas also cover the locations of observation stations that are virtually placed on uninhabited island surrounding the source area. During an actual volcanic tsunami event, a tsunami is expected to be observed at the observation stations. For real-time tsunami forecasting, the most suitable scenarios to reproduce the observed waveforms are searched quickly in the database. The precomputed results under the identified scenarios are further provided as input for rapid tsunami propagation simulation. Therefore, an effective real-time forecasting can be conducted to densely populated coastal areas located at a considerable distance from the source, such as the coasts of Java and Sumatra. The forecasting performance was examined by applying the method for three hypothetical collapse scenarios assuming different sliding directions. We demonstrated that the tsunamis along the coasts were successfully forecasted. Moreover, we showed that the combination of a pre-computed database and the existence of observation stations near the source area was able to produce appropriate tsunami forecasting for the coastal area even in a volcanic event.
• Short-wave run-ups of the 1611 Keicho tsunami along the Sanriku Coast
  Yusuke Yamanaka; Yuichiro Tanioka
  Progress in Earth and Planetary Science, 9, 1, Dec. 2022, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Tsunami inundation characteristics along the Japan Sea coastline: effect of dunes, breakwaters, and rivers
  Yusuke Yamanaka; Takenori Shimozono
  Earth, Planets and Space, 74, 1, Springer Science and Business Media {LLC}, Dec. 2022, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  Scientific journal, For Japanese coastal communities along the Japan Sea, where the risk of earthquake-induced tsunamis is deemed lower than that along the Pacific Ocean, tsunami disaster mitigation strategies have not been sufficiently developed. This study estimated the tsunami inundation characteristics for three major Japanese coastal cities along the Japan Sea. Based on tsunami simulations for representative coastal areas, we aimed to identify common vulnerabilities, which included those suggested by previous studies and local governments, to develop disaster mitigation strategies. Comprehensive simulations for tsunami propagation and inundation were performed for coastal areas in Akita City, Sakata City, and Niigata City based on earthquake and tsunami source scenarios developed by the Japanese Government for the Japan Sea area. To demonstrate the effectiveness of the estimated inundation characteristics, tsunami inundation was simulated for each coastal area under varying tsunami source conditions (including excessive tsunami magnitude) with a high resolution of the topography and infrastructure. Natural sand dunes, ports with man-made breakwaters, and rivers with levees are typical topographical features found in urbanized and densely populated areas along the Japan Sea coastline. According to the simulated results, the dunes and port breakwaters contribute significantly to decreasing the total amount of tsunami inundation for the areas behind them. However, the presence of the breakwaters also increases the tsunami heights in the areas immediately beyond the ports. Additionally, even the areas protected by the dunes might be exposed to an inundation risk in which the tsunamis invade a river channel, causing it to overflow. These findings were common to the coastal areas, and could be generally applicable to tsunami inundation for all coastal areas along the Japan Sea. Based on these results, the enhancement of existing infrastructure such as breakwaters and river levees should be the priority measure within tsunami risk-mitigation strategies; these, combined with natural resources such as dunes, can effectively mitigate tsunami disasters.
  
  
  Graphical Abstract
• ANALYSIS OF TSUNAMI SEDIMENT TRANSPORT OVER A SILTY BOTTOM BASED ON LABORATORY EXPERIMENT AND NUMERICAL MODELING
  Sohei JIMBO; Yusuke YAMANAKA; Takenori SHIMOZONO
  Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 78, 2, I_181, I_186, Japan Society of Civil Engineers, Nov. 2022, [Peer-reviewed], [Domestic magazines]
  Japanese, Scientific journal
• A COMPERATIVE STUDY OF RUNUP HEIGHTS BY WINTER STORM WAVES AND POTENTIAL TSUNAMIS ON THE SEA OF JAPAN COAST
  Takuto ISE; Takenori SHIMOZONO; Yusuke YAMANAKA
  Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 78, 2, I_211, I_216, Japan Society of Civil Engineers, Nov. 2022, [Peer-reviewed], [Domestic magazines]
  Japanese, Scientific journal
• Rapid assessment of tsunami source impacts on low-lying coastal areas using offshore wave superposition and static sweep of onshore terrain
  Yusuke Yamanaka; Takenori Shimozono
  Coastal Engineering Journal, 1, 17, Informa UK Limited, 03 Apr. 2022, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Characteristics of the deep sea tsunami excited offshore Japan due to the air wave from the 2022 Tonga eruption
  Yuichiro Tanioka; Yusuke Yamanaka; Tatsuya Nakagaki
  Earth, Planets and Space, 74, 1, Apr. 2022, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• Numerical investigation on characteristics of long wave components amplified under the 2018 Typhoons Jebi and Trami observed along the coast of Wakayama, Japan
  Yusuke Yamanaka; Yoshimitsu Tajima
  Coastal Engineering Journal, 64, 1, 1, 16, Informa UK Limited, 28 Nov. 2021, [Peer-reviewed], [Lead author], [International Magazine]
  English, Scientific journal
• Study on the 1906 Colombia‐Ecuador megathrust earthquake based on tsunami waveforms observed at tide gauges: release variation of accumulated slip‐deficits in the source area
  Yusuke Yamanaka; Yuichiro Tanioka
  Journal of Geophysical Research: Solid Earth, 126, 5, e2020JB021375, 02 Apr. 2021, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Frequency-dependent amplification of the Sanriku tsunamis in Ryori Bay
  Yusuke Yamanaka; Miyuki Nakamura
  Earth, Planets and Space, 72, 1, :6, Springer Science and Business Media {LLC}, Dec. 2020, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  Scientific journal
• 防波堤マウンドに作用する段波の水理特性と被覆ブロックの安定性に関する研究
  野田智也; 山中悠資; 田島芳満; 小関健斗
  土木学会論文集B2(海岸工学), 76, 2, I_691, I_696, Nov. 2020, [Peer-reviewed], [Domestic magazines]
  Scientific journal
• 海浜トレンチ調査による砂礫海岸形成機構の解明
  佐藤愼司; 野口賢二; 山中悠資; 与那嶺瑞輝
  土木学会論文集B2(海岸工学), 76, 2, I_571, I_576, Nov. 2020, [Peer-reviewed], [Domestic magazines]
  Scientific journal
• 日本海西部域における1833年庄内沖地震津波の広域沿岸挙動に関する研究
  山中悠資; 島津希来; 下園武範; 檜垣敬真
  土木学会論文集B2(海岸工学), 76, 2, I_271, I_276, Nov. 2020, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
  Scientific journal
• Numerical modeling of ship wave generation using Green’s functions based on linear dispersive wave theory
  Jumpei Morioka; Yoshimitsu Tajima; Yusuke Yamanaka; Magnus Larson; Yoshiaki Kuriyama; Takenori Shimozono; Shinji Sato
  Coastal Engineering Journal, 62, 2, 317, 335, Informa UK Limited, May 2020, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  Scientific journal
• Tsunami hazard in the Caribbean coast of Honduras due to large earthquakes occurred along the Cayman Trough at the northwest boundary of Caribbean plate
  Yuichiro Tanioka; Amilcar Geovanny Cabrera; Greyving Jose Arguello; Yusuke Yamanaka
  Coastal Engineering Journal, 62, 3, 405, 412, Mar. 2020, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• Study on the influence of infragravity waves on inundation characteristics at Minami-Ashiyahama in Osaka Bay induced by the 2018 Typhoon Jebi
  Naohiro Hattori; Yoshimitsu Tajima; Yusuke Yamanaka; Kenzo Kumagai
  Coastal Engineering Journal, 62, 2, 182, 197, Feb. 2020, [Peer-reviewed], [International Magazine]
  Scientific journal
• Nearshore Dynamics of Storm Surges and Waves Induced by the 2018 Typhoons Jebi and Trami Based on the Analysis of Video Footage Recorded on the Coasts of Wakayama, Japan
  Yusuke Yamanaka; Yoshinao Matsuba; Yoshimitsu Tajima; Ryotaro Shibata; Naohiro Hattori; Lianhui Wu; Naoko Okami
  Journal of Marine Science and Engineering, 7, 11, 413, 413, MDPI AG, Nov. 2019, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  Scientific journal, In this study, field surveys along the coasts of Wakayama Prefecture, Japan, were first conducted to investigate the coastal damage due to storm surges and storm-induced waves caused by the 2018 Typhoons Jebi and Trami. Special focus was placed on the characteristic behavior of nearshore waves through investigation of observed data, numerical simulations, and image analysis of video footage recorded on the coasts. The survey results indicated that inundation, wave overtopping, and drift debris caused by violent storm-induced waves were the dominant factors causing coastal damage. Results of numerical simulations showed that heights of storm-induced waves were predominantly greater than storm surge heights along the entire coast of Wakayama in both typhoons. However, computed gradual alongshore variations in wave and surge heights did not explain locally-concentrated inundation and run-up heights observed along the coasts. These results indicate that complex nearshore hydrodynamics induced by local nearshore bathymetry might have played a significant role in inducing such local wave characteristics and the associated coastal damage. Analysis of video footage recorded during Typhoon Jebi, for example, clearly showed evidence of amplified infragravity wave components, which could enhance inundation and wave run-up.
• UAVを用いた海岸情報マッピングに関する研究
  柴田涼太郎; 佐藤愼司; 山中悠資
  土木学会論文集B2(海岸工学), 75, 2, 1261, 1266, Oct. 2019, [Peer-reviewed], [Domestic magazines]
  Scientific journal
• 非定常性に着目した津波に対する防波堤マウンド被覆ブロックの安定性評価
  小関健斗; 山中悠資; 田島芳満; 下園武範
  土木学会論文集B2(海岸工学), 75, 2, 841, 846, Oct. 2019, [Peer-reviewed], [Domestic magazines]
  Scientific journal
• Inundation Characteristics in Arida City Due to Overtopping Waves Induced by 2018 Typhoon Jebi
  Yusuke Yamanaka
  Proceedings of the 10th International Conference on Asian and Pacific Coasts, APAC2019, 199, 206, Sep. 2019, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  Scientific journal
• Development of an imagery-based monitoring system for nearshore bathymetry by using wave breaking density
  Naohiro Hattori; Shinji Sato; Yusuke Yamanaka
  Coastal Engineering Journal, 61, 3, 308, 320, Informa {UK} Limited, 03 Jul. 2019, [Peer-reviewed], [International Magazine]
  Scientific journal
• 2018 Typhoon Jebi post-event survey of coastal damage in the Kansai region, Japan
  Nobuhito Mori; Tomohiro Yasuda; Taro Arikawa; Tomoya Kataoka; Sota Nakajo; Kojiro Suzuki; Yusuke Yamanaka; Adrean Webb; Tomoyuki Takahashi; Sooyoul Kim; Susumu Araki; Yoko Shibutani; Takashi Yamano; Daiki Sakai; Tomohiro Takagawa; Naoki Tsuruta; Shingo Kawaguchi; Syota Asahi; Takashi Fujiki; Takumu Iwamoto; Yu Chida; Tomoya Shibayama; Miguel Esteban; Tomoyuki Takabatake; Ryota Nakamura; Kohji Uno; Tetsuya Kakinoki; Yasuo Nihei; Daisuke Inazu; Takaaki Shigematsu; Kazunori Sameshima; Kazuhiko Honda; Daiki Satomura; Ibuki Tsujisawa; Kentaro Kumagai; Noriki Sugahara; Shoichi Emoto; Yoshimitsu Tajima
  Coastal Engineering Journal, 61, 3, 278, 294, 03 Jul. 2019, [Peer-reviewed], [International Magazine]
  Scientific journal
• Method for Near-Real Time Estimation of Tsunami Sources Using Ocean Bottom Pressure Sensor Network (S-Net)
  Mayu Inoue; Yuichiro Tanioka; Yusuke Yamanaka
  GEOSCIENCES, 9, 7, 310, Jul. 2019, [Peer-reviewed], [International Magazine]
  English, Scientific journal
• Study on the comprehensive countermeasures for coastal erosion of Kujukuri Beach
  Ryotaro Shibata; Shinji Sato; Yusuke Yamanaka
  Coastal Engineering Journal, 61, 2, 256, 265, Informa {UK} Limited, 03 Apr. 2019, [Peer-reviewed], [International Magazine]
  Scientific journal
• Generation mechanism of large later phases of the 2011 Tohoku-oki tsunami causing damages in Hakodate, Hokkaido, Japan
  Yuichiro Tanioka; Mizuho Shibata; Yusuke Yamanaka; Aditya Riadi Gusman; Kei Ioki
  PROGRESS IN EARTH AND PLANETARY SCIENCE, 6, 30, Mar. 2019, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A numerical study on nearshore behavior of Japan Sea tsunamis using Green’s functions for Gaussian sources based on linear Boussinesq theory
  Yusuke Yamanaka; Shinji Sato; Takenori Shimozono; Yoshimitsu Tajima
  Coastal Engineering Journal, 61, 2, 187, 198, Feb. 2019, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  Scientific journal
• Study on characteristics of synthetic aperture radar (SAR) imagery around the coast for shoreline detection
  Lianhui Wu; Yoshimitsu Tajima; Yusuke Yamanaka; Takenori Shimozono; Shinji Sato
  Coastal Engineering Journal, 61, 2, 152, 172, Informa UK Limited, Dec. 2018, [Peer-reviewed], [International Magazine]
  Scientific journal
• Large amplification of the 1906 Colombia-Ecuador earthquake tsunami in Hilo Bay induced by bay-scale resonance
  Yusuke Yamanaka; Yuichiro Tanioka
  GEOPHYSICAL JOURNAL INTERNATIONAL, 214, 3, 1937, 1946, Sep. 2018, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• Simulation of a Dispersive Tsunami due to the 2016 El Salvador-Nicaragua Outer-Rise Earthquake (M-w 6.9)
  Yuichiro Tanioka; Amilcar Geovanny Cabrera Ramirez; Yusuke Yamanaka
  PURE AND APPLIED GEOPHYSICS, 175, 4, 1363, 1370, Apr. 2018, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
  English, Scientific journal
• A parametric study of tsunami fission generation in a bay geometry based on numerical simulation
  Yusuke Yamanaka; Shinji Sato; Takenori Shimozono; Yoshimitsu Tajima
  Coastal Engineering Journal, 60, 1, 22, 38, Jan. 2018, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  Scientific journal
• A long source area of the 1906 Colombia-Ecuador earthquake estimated from observed tsunami waveforms
  Yusuke Yamanaka; Yuichiro Tanioka; Takahiro Shiina
  EARTH PLANETS AND SPACE, 69, 163, Dec. 2017, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• EXPERIMENTAL STUDY OF WAVE FORCE IN A SUPERIMPOSED WAVEFIELD WITH BORES AND SHORT WAVES
  YAMANAKA Yusuke; TAJIMA Yoshimitsu
  Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 73, 2, 391, 396, Japan Society of Civil Engineers, Oct. 2017, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
  Japanese,  Some reports for the cases such as the 2011 Tohoku Tsunami and the 2013 Typhoon Haiyan pointed out that the coastal damages expanded due to the short waves which come together with the long wave. The objective of this study is to investigate characteristics of wave force in such wavefield based on laboratory experiments. Characteristics of the wave forces measured by wave pressure sensors were examined with waveforms estimated by image analysis of video footage during the experiment. It was found that the vertical acceleration of the water motion due to short waves was one of the influential factors for the wave force. It was also found that the location change of wave breaking induced by the interaction between short and long waves maximizes the impulsive breaker force of short waves affecting the structure, and it could be dominant rather than that of the long wave.
• AN EFFICIENT INUNDATION MODEL FOR TSUNAMI RISK ASSESSMENT OF NUMEROUS LOW-LYING AREAS ALONG A LONG COASTLINE
  HIGASHI Ryota; SHIMOZONO Takenori; YAMANAKA Yusuke
  Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 73, 2, 1483, 1488, Japan Society of Civil Engineers, Oct. 2017, [Peer-reviewed], [Domestic magazines]
  Japanese,  An efficient inundation model was developed for tsunami risk assessment of numerous low-lying areas along a long coastline. The inundation model is based on the level fill method, which inputs water into a coastal low-lying area protected by a levee using the overflow formulas. In order to apply the model to numerous low-lying areas, a topographic database of each low-lying area was created for a model input. The model validation was carried out by applying it to the 2011 Tohoku tsunami case. The results show that the model gives reasonable estimation of inundated areas although significant underestimation occurs in areas where levees were actually breached. We also examined the sensitivity of the inundated area to the levee height to discuss the levee protectablity in different low-lying areas.
• Estimating the Topography Before Volcanic Sector Collapses Using Tsunami Survey Data and Numerical Simulations
  Yusuke Yamanaka; Yuichiro Tanioka
  PURE AND APPLIED GEOPHYSICS, 174, 8, 3275, 3291, Aug. 2017, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
  English, Scientific journal
• A STUDY ON SOLITON FISSION OF NANKAI TROUGH TSUNAMI
  YAMANAKA Yusuke; SATO Shinji; TAJIMA Yoshimitsu; SHIMOZONO Takenori
  Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 72, 2, 403, 408, Japan Society of Civil Engineers, Nov. 2016, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
  Japanese,  The generation of the soliton fission was investigated for the Nankai Trough giant tsunami. Four bays were selected as target sites prone to the soliton fission on the basis of nearshore geometries in the bay. The generation of the soliton fission in the respective site was judged by using a parametric diagram developed on the basis of 1-D tsunami simulation with the Boussinesq equation. The tsunami source was assumed by the Cabinet Office model. The result of the analysis demonstrated that the soliton fission is likely to develop in the Owase Bay and the Suzaki Bay owing to the amplification due to the resonance in the both bays.
• A STUDY ON COMPREHENSIVE TSUNAMI COUNTERMEASURES BASED ON TSUNAMI RISK ANALYSIS FOR WEST COAST OF THE IZU PENINSULA
  YAMAZAKI Asuka; SATO Shinji; YAMANAKA Yusuke
  Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 72, 1, 71, 82, Japan Society of Civil Engineers, Nov. 2016, [Peer-reviewed], [Domestic magazines]
  Japanese,  Tsunami risk was analyzed on the basis of tsunami flood simulation for three towns, Heda, Toi and Matsuzaki located on the west coast of the Izu Peninsula, Shizuoka Prefecture. Existing annual tsunami risks for the three towns were found to be in the range from 180 to 230 million yen/year. Risk reduction due to quick evacuation was compared with that due to seawall construction. Long-term risk reduction in 50 years was projected by considering population decrease and relocation encouragement from flooding zones. It is considered that the risk analysis in this study helps to establish a comprehensive and rational tsunami mitigation plan.
• STUDY ON THE MECHANISM OF INUNDATION CHARACTERISTICS AROUND THE SAN PEDRO BAY INDUCED BY TYPHOON HAIYAN
  TAGUCHI Yusuke; TAJIMA Yoshimitsu; NAKAMURA Shunichiro; YAMANAKA Yusuke
  PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 71, 2, 1675, 1680, Japan Society of Civil Engineers, Nov. 2015, [Peer-reviewed], [Domestic magazines]
  Japanese, This study aims to investigate the mechanisms of observed inundation characteristics around the San Pedro bay induced by Typhoon Haiyan. Numerical analysis was first carried out to overview the characteristics of storm surge and stormy waves. It was found through the analysis that strong anti-clockwise circulating current was developed in the San Pedro bay. Laboratory experiment was then conducted to investigate the interactions of strong current and waves. It was found through the experiment that the strong current dramatically changes the dissipations of stormy waves and this feature may reasonably explain the observed inundation characteristics especially around the mouth of San Pedro bay.
• STUDY ON TSUNAMI DAMAGE MECHANISM IN FUKUSHIMA PREFECTURE FOCUSING ON THE GENERATION OF BORES
  OKUMA Shohei; SATO Shinji; YAMANAKA Yusuke; SANUKI Hiroshi
  PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 71, 1, 58, 68, Japan Society of Civil Engineers, Oct. 2015, [Peer-reviewed], [Domestic magazines]
  Japanese, Destruction mechanisms of coastal structures due to the 2011 Tohoku Tsunami were investigated on the basis of field surveys in Fukushima Prefecture. Severe destruction appeared to be developed by the action of breaking bores. Laboratory experiments demonstrated that the angle of the tsunami front was an essential parameter for the generation of breaking bores. Larger wave force was observed as the angle of the tsunami front became steeper. Numerical simulation revealed that such a steep tsunami was developed in the central part of Fukushima Prefecture, where the reflection of the preceding tsunami by coastal cliff enhanced the steepness of the largest tsunami.
• Tsunami sediment analysis based on luminescence measurement
  Shinji Sato; Kanto Nishiguchi; Yusuke Yamanaka
  Proceeding of Coastal Sediments, May 2015, [Peer-reviewed], [International Magazine]
  International conference proceedings
• Estimation of Tsunami Wave Force on Collapsed Coastal Dyke in the Ryori Bay
  YAMANAKA Yusuke; SATO Shinji; TAJIMA Yoshimitsu
  PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 70, 2, 201, 205, Japan Society of Civil Engineers, Nov. 2014, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
  Japanese, Scientific journal, This study aims at the estimation of tsunami wave force due to the 2011 Tohoku earthquake tsunami. Field survey in Ryori, Iwate Prefecture, suggested multiple mechanisms for the collapse of 8.6 m high coastal dikes. Numerical tsunami simulation based on the nonlinear dispersive wave theory revealed the concentration of tsunami-induced flow to the northern area which is considered to develop severe scour of the foundation. The model also simulated the large wave force was exerted to the dike due to the tsunami overflow as well as the impulsive breaker force due to 10m high short period wave generated at the wave front. The estimated wave force was consistent with the collapse of the parapet observed in the field study.
• Development of A Fast Tsunami Simulation System Based on The Linear Boussinesq Theory
  YAMANAKA Yusuke; SATO Shinji; TAJIMA Yoshimitsu; SHIMOZONO Takenori; SANUKI Hiroshi
  PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 70, 2, 206, 210, Japan Society of Civil Engineers, Nov. 2014, [Peer-reviewed], [Lead author, Corresponding author]
  Japanese, A fast tsunami simulation system was developed which utilized the superposition of point source computations stocked as a database. The single point source was represented by the Gaussian distribution with s=5 km. The propagation of the point source was computed by using the linear Boussinesq theory. The accuracy of the model was discussed in representing the actual tsunami source profile as well as in the dispersive tsunami propagation. The system was applied to a hypothetical Japan Sea tsunami used in the disaster mitigation planning of Tottori Prefecture. The system successfully displayed the sensitivity of local tsunami height to the tsunami source location and thus demonstrated the performance to assist specific evacuation planning in individual towns and cities.
• Analysis of Paleo Tsunami by Luminescence Measurement of Beach Sand
  NISHIGUCHI Kanto; SATO Shinji; YAMANAKA Yusuke; TAKEMORI Ryo
  PROCEEDINGS OF THE JAPANESE CONFERENCE ON COASTAL ENGINEERING, 70, 2, 291, 295, Japan Society of Civil Engineers, Nov. 2014, [Peer-reviewed]
  Japanese, Luminescence measurements of coastal sand particles were applied to the analysis of paleo tsunami generated by a Japan Sea earthquake in 1833. Long-term coastal morphology was described for a 20 km sandy beach formed by fluvial sediments supplied from the Hinogawa River. The alongshore distribution of the thermo-luminescence of beach sand and the comparison of shoreline in old maps indicated historical beach erosion at old river mouth and westward longshore sand transport. The vertical distribution of the optically-stimulated-luminescence of a sediment core sampled 420 m inland from the present shoreline suggested coastal and aeolian accretion processes interrupted by a 7 cm thick tsunami sediment layer. Numerical tsunami simulation supported the movement of beach sand due to flooding tsunami.
• Sensitivity Analysis of Damages around Katsushika Ward, Tokyo, Dependent on Locations of Levee Breach along the Arakawa River
  Yusuke Yamanaka; Nanae Kita; Yoshimitsu Tajima; Takaaki Kato
  Proceeding of International Alliance for Sustainable Urbanization and Regeneration, 95, 102, Oct. 2014, [Peer-reviewed]
• 東北地方太平洋沖地震津波の綾里湾における増幅機構
  山中悠資; 佐藤愼司; 田島芳満
  土木学会論文集B2(海岸工学), 69, 2, 171, 175, Nov. 2013, [Peer-reviewed], [Lead author, Corresponding author]
• Analysis of Paleo Tsunami by Optically Stimulated Luminescence Dating of Tsunami Sediments
  西口幹人; 劉海江; 佐藤愼司; 田島芳満; 山中悠資
  土木学会論文集B2(海岸工学), 69, 2, 291, 295, 土木学会, Nov. 2013, [Peer-reviewed]
  Japanese
• Dynamic behaviors of the 2011 Tohoku Tsunami in Ryori bay
  Yusuke Yamanaka; Yoshimitsu Tajima; Shinji Sato; Haijiang Liu
  Proceeding of Coastal Dynamics, 1937, 1946, Jun. 2013, [Peer-reviewed], [Lead author, Corresponding author]
• ビデオ画像解析に基づく綾里湾白浜海岸に集中した津波外力場特性の分析
  山中悠資; 田島芳満; 佐藤愼司
  土木学会論文集B2(海岸工学), 68, 2, 341, 345, Nov. 2012, [Peer-reviewed], [Lead author, Corresponding author]
• Gravel Movement on a Sand-Gravel Mixed Beach Based on RFID technique
  IYAGAWA Ryuichi; TAKAGAWA Tomohiro; SATO Shinji; NAGASAKA Yosuke; YAMANAKA Yusuke
  Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), 68, 2, 491, 495, Japan Society of Civil Engineers, Nov. 2012, [Peer-reviewed]
  Japanese, Gravel movement on sand-gravel mixed beaches was investigated by using RFID technique which detects individual gravel tagged with a passive IC tag. At the same time, variation of the foreshore beach topography was recorded by RTK-GPS. Gravel movement mechanism and the corresponding beach face change were studied on the basis of seven field surveys performed in the period from January to February 2012. On the target beach, storm waves tended to transport many gravels onshore and develop a steep beach face. In contrast, downwash motion by moderate waves moved gravels offshore although a small amount of gravels was exchanged across the shoreline simultaneously. The movement of gravels on the foreshore appeared to be influenced by the presence of submerged breakwaters.
• Study on the Erosion Mechanisms of Soil Embankment by Tsunamis
  長坂陽介; HarryYEH; 中尾秀之; 佐藤愼司; 田島芳満; 山中悠資
  土木学会論文集B2(海岸工学), 68, 2, 1331, 1335, 土木学会, Nov. 2012, [Peer-reviewed]
  Japanese
• Cohherency of quality factor of subsurface ground identified using vertical array records of earthquake motions
  Osamu Tsujihara; Yusuke Yamanaka
  Proceeding of 9th U.S. National and 10th Canadian Conference on Earthquake Engineering, No.838, Jul. 2010, [Peer-reviewed]
• IMPROVEMENT OF SWEEPING METHOD IN IDENTIFICATION PROBLEM OF SUBSURFACE GROUND STRUCTURE AND ITS APPLICABILITY
  TSUJIHARA Osamu; YAMANAKA Yusuke
  PROCEEDINGS OF THE JSCE EARTHQUAKE ENGINEERING SYMPOSIUM, 65, 1, 195, 201, Japan Society of Civil Engineers, 2009, [Peer-reviewed]
  Vertical array observations of ground motions have been energetically carried out in Japan. They give us important information to identify the dynamic properties of subsurface ground. Some methods were proposed for the identification of shear wave velocity and quality factor. The accuracy of the identification of shear wave velocity has been improved. However, the improvement of accuracy is not very notable in the identification of quality factor. In this study, the sweeping method, in which the quality facor is estimated only at the frequency where the quality facor is sensitive, is modified so as to enable the extraction of more reliable information. Applying it to the identification of KiK-net sites, the coherency of identified quality facor at the identical site using the ground motions in the different events of earthquake is discussed.

• 自然史科学論文講読１, 2024年, 修士課程, 理学院
• 地球計測実習, 2024年, 学士課程, 理学部
• 自然史科学特別研究１, 2024年, 修士課程, 理学院
• 一般教育演習(ﾌﾚｯｼｭﾏﾝｾﾐﾅｰ), 2024年, 学士課程, 全学教育

• JAPAN GEOSCIENCE UNION
• THE SEISMOLOGICAL SOCIETY OF JAPAN
• JAPAN SOCIETY OF CIVIL ENGINEERS

• 基盤・映像観測網の融合による津波観測・予測体系の革新
  科学研究費助成事業
  01 Apr. 2026 - 31 Mar. 2030
  山中 悠資
  日本学術振興会, 基盤研究(B), 北海道大学, 26K00787
• Development of combined source modeling of ground motion and tsunamis to mitigate damaging earthquakes and tsunamis
  Grants-in-Aid for Scientific Research
  01 Apr. 2026 - 31 Mar. 2029
  三宅 弘恵; 山中 悠資; 浅野 公之; 対馬 弘晃
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), The University of Tokyo, 26K01178
• 海底光ファイバDASによる巨大津波観測手法の開拓
  科学研究費助成事業
  Jun. 2026 - Mar. 2029
  山中 悠資; 福島 駿
  日本学術振興会, 挑戦的研究(萌芽), 北海道大学, 26K22362
• 世界中の大規模爆発的噴火の規模をリアルタイム推定するシステムの開発
  科学研究費助成事業
  Apr. 2025 - Mar. 2029
  高橋 浩晃; 吉澤 和範; 青山 裕; 山中 悠資
  日本学術振興会, 基盤研究(B), 北海道大学, 25K01074
• 沿岸津波観測記録を用いた高精度波源推定に関する研究
  Grants-in-Aid for Scientific Research Grant-in-Aid for Early-Career Scientists
  Apr. 2020 - Mar. 2023
  山中 悠資
  本研究は、水槽実験と数値実験の結果に基づき、沿岸域において観測される津波波形を用いた波源推定技術を高度化させることを研究の目的としている。
  本年度は主に水槽実験を行い、定量的な計測データを蓄積した。水槽実験では断面二次元水槽を用い、水槽内に設置したゲートの急開(ダムブレイク)により津波を想定した段波を発生させることができる。波高や波形勾配が異なる様々な段波を発生させ、その水位変動および伝播過程を計測した。このようにして得られた実験結果に対して数値計算に基づく再現計算を行った。発生させた段波は水槽内の初期水深条件などに応じて様々な形態に遷移しながら伝播するが、その再現に適した数値モデルを選択して用いることで、実験結果を数値計算により比較的良好に再現できることを確認した。
  1906年にコロンビア沖で発生した地震津波の波源を、沿岸域で観測されたその津波波形に基づき推定した。その推定波源をスケーリングしながら様々な規模の波源を仮想的に想定し、それらの伝播を二つの異なる数値モデル(線形長波モデルおよび非線形長波モデル)に基づき推定した。これらの結果に基づき、沿岸域で観測されることが期待される波形を両モデルから推定したところ、津波による水位上昇量が大きくなるほど期待される波形のズレが大きくなった。これは津波の非線形性の考慮の有無により生じる結果である。また沿岸域で数十cm程度の比較的小規模の津波でも、得られる波形は数値モデルによって異なることが確認された。この結果、観測津波波形に基づく波源推定において、津波の非線形性の影響を評価することの重要性が示された。
  Japan Society for the Promotion of Science, Grant-in-Aid for Early-Career Scientists, The University of Tokyo, 20K14563
• 沿岸地形の簡約化による広域低地群の浸水被害予測体系の構築
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
  Apr. 2018 - Mar. 2021
  Takenori Shimozono
  The study develops a new model framework for coastal flooding by tsunamis and storm surges, which enables an efficient hazard assessment of numerous small coastal communities along a long stretch of coastline. The model represents coastal low-lying areas as networks of their small subdomains and solve transfers of mass and momentum among the subdomains based on the linear shallow water equations. It is capable of simulating coastal flood processes with a smaller number of computational elements compared to conventional grid-based models. Model applications to past flood events confirmed that it achieves a good balance of accuracy and computational cost.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), The University of Tokyo, 18H01541
• Innovation of beach nourishment technology for erosion control based on multi-aspect analyses of beach topography and sediments
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
  Apr. 2018 - Mar. 2021
  SATO Shinji
  Beach trench surveys were conducted on sand gravel beaches in Miyazaki and Kochi Coast. The survey in Kochi Coast was conducted on a beach protected by detached breakwaters. Alongshore and cross-shore trenches were excavated with a total length of 150m. The trench faces were recorded by a RTK-UAV and compared with topography data. A clear boundary between sand and gravel layers was observed at a level of 2m above sea level. The bottom gravel layers were considered to be developed by swash waves at the construction of detached breakwaters. The beach was found to be eroded by several high waves in last 15 years. The erosion level, however, was found to be up to the level of sand-gravel boundary, which implied that the sand gravel beach protected by detached breakwaters was resistant to erosion owing to the presence of buried gravel layers.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Kochi University of Technology, 18H01539
• Understanding of tsunami events due to great earthquakes occurred in Japan Sea and their tsunami forecast
  Grants-in-Aid for Scientific Research
  01 Apr. 2015 - 31 Mar. 2019
  Tanioka Yuichiro; Ioki Kei; Yamanaka Yusuke; Razjigaeva Nadezhda; Ganzey Larisa; Kaistrenko Victor
  We conducted tsunami deposit surveys at various locations in Primorsky, identified tsunami events, and estimated the age of the events. For tsunamis around the 12th century, a fault model that can explain tsunami deposits on the coast of Hokkaido was estimated by using the tsunami numerical simulation. The total fault length was estimated to be 109 km, and a large slip of 18m was estimated at a 50 km fault on the north side. This estimate is much larger than the previous estimate of 6m. It has become clear that the fault model of the 12-century earthquake is located just between the fault model of the 1993 Hokkaido Nansei-oki earthquake and the fault model of the 1983 Japan Sea earthquake. In addition, the tsunami caused by the volcanic sector collapse due to the eruption of the Oshima-Oshima volcano in 1741 is reproduced by the numerical simulation.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 15H05133
• 波源推定の不確実性が沿岸域の津波挙動に及ぼす影響に関する研究
  Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows
  Apr. 2016 - Mar. 2019
  山中 悠資
  本年度は日本海域で想定されている地震津波断層を用いて、沿岸域で予想される津波挙動を詳細に分析した。まず、複数の断層による連動型地震が想定されている断層を対象として、それにより形成される津波の伝播計算を行った。次にその構成断層各々が単独で地震を発生させる場合を想定し、同様にそれによる津波の伝播計算を行った。一般的には連動地震の方が地震規模が大きくなり、形成される津波規模も大きくなるが、これらの伝播計算結果の比較から、沿岸域においては単独地震による津波の方が連動地震による津波よりも局所的に津波高が大きくなる場合があることがわかった。
  上述の結果から、各沿岸域単位で予想される津波挙動を分析する必要があることがわかったため、鳥取県及び島根県に位置する美保湾を分析対象としてさらに詳細な分析を実施した。まず上述の分析と同様に想定されている地震津波断層を用いて津波の伝播計算を行い、美保湾における津波の挙動を推定した。その結果、特に日本海東縁部及び北海道周辺海域で形成された津波においては、美保湾では第一波目ではなく後続波で津波高が最大になる傾向があることがわかった。さらに、沿岸部固有振動によってその後続波が大きくなっている可能性があることがわかった。これを踏まえて、美保湾で励起されやすい津波の振動成分の推定及び、それと各津波断層が形成しやすい津波の振動成分の比較を行った。その結果、美保湾に影響が大きかった地震津波断層が励起しやすい津波の振動成分と湾内で見られたその振動成分が整合的であることがわかった。したがって、本研究の手法を用いることにより、各地震津波断層が各沿岸域で形成しやすい津波特性を予察的に推定することが可能であることがわかった。
  Japan Society for the Promotion of Science, Grant-in-Aid for JSPS Fellows, 16J00394
• 津波・波浪流体運動のマルチスケールモデルの構築に基づく沿岸防災技術の考究
  Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows
  Apr. 2013 - Mar. 2016
  山中 悠資
  前年度までの研究により，2011年東北津波が来襲した岩手県綾里湾では波の分裂現象(ソリトン分裂)が生じていたことや，それが綾里湾の海岸堤防の破壊に寄与した可能性などが明らかになっている．このように，津波のソリトン分裂は沿岸構造物の破壊に影響を与えることや氾濫域を拡大させることがあるため，その発生可能性を考慮しながら津波防災計画を策定する必要があると考えられる．防災計画策定の際には数値計算を行い，津波の伝播・氾濫を予測するが，その発生を考慮した詳細な数値計算は計算負荷が非常に大きくなる．そこで，まずソリトン分裂の発生を考慮した数値実験を行ってそれが発生する津波及び地形条件を抽出した．それに基づき，ソリトン分裂発生の判定図を作成した．実際にソリトン分裂が発生した地域を対象としてその判定図を2011年東北津波に適用し，詳細な数値計算を行わなくてもその発生を予測できることを確認した．この手法を現在想定されている南海トラフ巨大地震津波に適用し，ソリトン分裂が発生する可能性がある地域を示した．
  適切な防災計画を策定するためには，各地域に来襲する津波波形を事前に精度良く把握しておく必要がある．しかしながら，数多くの想定津波を対象にしながら各地域に来襲する津波波形をそれぞれ把握することは，計算負荷の観点からも非効率的である．そこで，前年度に構築した，日本海津波を対象とした津波計算システムに基づき，沖合任意地点における津波波形を高速に計算することができるウェブサイトを開設した．同サイトでは日本海東縁部を波源とする任意津波の波形を計算することができる．これを活用することで，日本海沿岸域の防災計画の策定を効率的に行うことができる．
  Japan Society for the Promotion of Science, Grant-in-Aid for JSPS Fellows, The University of Tokyo, 13J02058