Reconstruction of paleoseismological events based on the seismic driving model

2020 Fiscal Year Final Research Report

• Project/Area Number: 17H02074
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Natural disaster / Disaster prevention science
• Research Institution: Tohoku University (2019-2020); Museum of Natural and Environmental History, Shizuoka (2017-2018)
• Principal Investigator: Sugawara Daisuke 東北大学, 災害科学国際研究所, 准教授 (50436078)
• Co-Investigator(Kenkyū-buntansha): 北村 晃寿 静岡大学, 理学部, 教授 (20260581)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 古地震 / 古津波 / 海岸地形 / 堆積物 / 地下レーダー

Outline of Final Research Achievements

In this study, relationship between formation and development of coastal topography and paleo-earthquake and tsunami were examined. In the Shimizu Plain, Shizuoka City, a large-scale coseismic uplift that took place around ca. 400 AD was identified based on the analysis of data from ground-penetrating radar (GPR) and sedimentary deposits. In Makinohara City, a possible tsunami deposit dated at early 4th to 5th century was detected. This coincides with the ca. 400 AD uplift in the Shimizu Plain. An increase in sediment supply to the coast 150 years after the tsunami was inferred from the GPR and sediment data. In Yaidzu City, a prehistoric and three historic tsunami deposits were found from the GPR and sediment data. A large-scale landslide due to 1096 Tokai earthquake and resulting development of coastal topography was inferred based on the analysis of the data.

Free Research Field

地質学

Academic Significance and Societal Importance of the Research Achievements

従来とは異なる観点から、より多くの地域・時代について古地震・古津波履歴を復元しリスク評価を行うための手法として、巨大地震後の海岸地形の形成・発達の調査研究が有効であることを示した。ひとつの地震がどのように海岸地形に反映されるのかは、地域によって異なるであろう。今後、同様の調査研究を進めていくことで、国内各地における地震・津波の履歴とリスクに対する理解を深め、適切な対応の検討に資する知見を提示できると考えられる。