Tsunami risk assessment for a caldera-forming eruption

• Project/Area Number: 17H06606
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Geology
• Research Institution: The University of Tokyo
• Principal Investigator: YAMADA Masaki 東京大学, 地震研究所, 特任研究員 (40806402)
• Research Collaborator: SATAKE Kenji ; MAENO Fukashi ; FUJINO Shigehiro ; KUSUMOTO Satoshi ; WANG Yuchen
• Project Period (FY): 2017-08-25 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000); Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 鬼界カルデラ噴火 / 火砕流 / 火山性津波 / 津波堆積物 / 鬼界アカホヤ噴火 / 津波シミュレーション

Outline of Final Research Achievements

This study aimed to unravel the tsunami size and triggering volcanic phenomena by numerical simulations of both caldera collapse and pyroclastic flow tsunamis, based on the widely-distributed tsunami deposit associated with the eruption. The tsunami deposit was identified at coastal lowlands in Oita, Tokushima, and Wakayama prefectures. The simulation results indicate that the tsunami generated by caldera collapse can arrive and inundate at the distant locations while the tsunami generated by pyroclastic flow is probably not powerful enough to form a tsunami deposit there.

Academic Significance and Societal Importance of the Research Achievements

カルデラを形成するような大規模噴火は極めて低頻度で発生するイベントであるため，実際に観測することは難しい．本研究では，火山噴出物などに関する先行研究によって噴火の規模や様子が概ね分かっている鬼界カルデラ噴火を研究対象にし，また地質記録と数値計算を組み合わせたことで，7300年前の鬼界カルデラ噴火に伴って同時に発生したと考えられている巨大津波の規模と発生要因をある程度明らかにすることができた．世界中の浅海域に火山は多く存在しており，本研究成果は大規模噴火を起こした際に発生し得る津波のリスク評価に貢献すると言える．

Research Products

• [Journal Article] Redeposition of volcaniclastic sediments by a tsunami 4600?years ago at Kushima City, south-eastern Kyushu, Japan (2019)
  • Author(s): Yamada Masaki、Fujino Shigehiro、Chiba Takashi、Goto Kazuhisa、Goff James
  • Journal Title: Sedimentology Volume: 印刷中 Issue: 3 Pages: 1354-1372
  • DOI: 10.1111/sed.12547
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Geological record of prehistoric tsunamis in Mugi town, facing the Nankai Trough, western Japan (2019)
  • Author(s): Shimada Yumi、Fujino Shigehiro、Sawai Yuki、Tanigawa Koichiro、Matsumoto Dan、Momohara Arata、Saito-Kato Megumi、Yamada Masaki、Hirayama Eri、Suzuki Takahiro、Chagu? Catherine
  • Journal Title: Progress in Earth and Planetary Science Volume: 6 Issue: 1
  • DOI: 10.1186/s40645-019-0279-9
  • NAID: 120007133452
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] The sedimentary record and numerical simulation of a tsunami associated with the 7.3 ka eruption of the Kikai volcano, Japan (2019)
  • Author(s): Yamada, M., Wang, Y., Maeno, F., Fujino, S., Satake, K.
  • Organizer: 20th Congress of the International Union for Quaternary Research (INQUA) 2019
  • Int'l Joint Research
• [Presentation] Numerical Simulation of a Tsunami Generated by the 7.3 Ka Caldera-forming Eruption of the Kikai Volcano, Japan (2018)
  • Author(s): Yamada, M., Wang, Y., Maeno, F., Fujino, S., Satake, K.
  • Organizer: AOGS 15th Annual Meeting
  • Int'l Joint Research
• [Presentation] 別府湾沿岸地域で発見された古津波堆積物 (2018)
  • Author(s): 山田昌樹，千葉 崇，Catherine Chague，篠崎鉄哉，藤野滋弘
  • Organizer: 第35回歴史地震研究会
• [Presentation] 鬼界カルデラ噴火に伴う津波堆積物と火山噴出物の層序関係 (2018)
  • Author(s): 山田昌樹，藤野滋弘，佐竹健治
  • Organizer: 日本堆積学会2018年秋田大会
• [Presentation] Geological Evidence for Tsunamis and Crustal Movements associated with Intraplate Earthquakes in Beppu Bay, Japan (2017)
  • Author(s): Yamada, M., Fujino, S., Chiba, T., Chague, C.
  • Organizer: The 5th International Tsunami Field Symposium
  • Int'l Joint Research
• [Presentation] 広域に分布するアカホヤ津波堆積物の識別 (2017)
  • Author(s): 山田昌樹，藤野滋弘，佐竹健治
  • Organizer: 日本地質学会第124年学術大会
• [Presentation] Geological Evidences for a Large Tsunami Generated by the 7.3 ka Kikai Caldera Eruption, Southern Japan (2017)
  • Author(s): Yamada, M., Fujino, S., Satake, K.
  • Organizer: 2017 AGU Fall Meeting
  • Int'l Joint Research
• [Remarks] Masaki Yamada
  • URL: https://sites.google.com/site/masakiyamada1231/home?authuser=0
• [Remarks] Masaki Yamada
  • URL: https://sites.google.com/site/masakiyamada1231/