Development of flood damage trace investigation method by magnetic susceptibility anisotropy of sedimentary soil and challenge to elucidate disaster scenario

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K21055
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 25:Social systems engineering, safety engineering, disaster prevention engineering, and related fields
• Research Institution: University of Toyama
• Principal Investigator: Kimura Ichiro 富山大学, 学術研究部都市デザイン学系, 教授 (60225026)
• Co-Investigator(Kenkyū-buntansha): 酒井 英男 富山大学, 理学部, 客員教授 (30134993) ; 泉 吉紀 サレジオ工業高等専門学校, その他部局等, 講師 (60793669) ; 立石 良 富山大学, 学術研究部都市デザイン学系, 准教授 (30823322)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: 帯磁率異方性 / 河川

Outline of Final Research Achievements

This research uses the magnetic susceptibility and its anisotropy (AMS) in river sediment, which records the flow regime during deposition, to obtain information on the flow characteristics during past floods. Laboratory experimental results of with an open channel flume indicate correlations between running water, the magnetic susceptibility anisotropy tensor, and the three axes of the particle ellipsoid measured with X-ray CT scan. It was suggested that the AMS could be a powerful research method for river engineering. In addition, a characteristic phenomenon was found that the minimum axis of the magnetic susceptibility ellipsoid tilts upstream from the vertical direction, and the maximum axis concentrates parallel to the flow direction.

Free Research Field

水理学

Academic Significance and Societal Importance of the Research Achievements

堆積時の流況と土砂粒子の帯磁率および粒子配列の相互の関係を系統的かつ制御された実験条件のもとで検討した事例はこれまでほとんど例がなく，新規性が高い研究といえる．特に，河川工学分野では帯磁率を計測に利用する発想がこれまでほとんどなかったため，学術的に意義が高いと考えられる．一方，最近増加しつづける河川災害の減災に向けて，過去の洪水痕跡調査はその手掛かりをしる有益な方法であり，本研究で用いた手法や知見はこのような分野にも貢献でき，社会的意義も大きい．