Studies of tsunami and storm deposits in NE Japan and Bangladesh.

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K03778
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 17040:Solid earth sciences-related
• Research Institution: Shinshu University
• Principal Investigator: HOYANAGI Koichi 信州大学, 学術研究院理学系, 特任教授 (30202302)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: tsunami depsoits / storm surge deposits / global warming / sea level rise / 井田川低地 / GBM Delta / 津波堆積物 / 高潮堆積物

Outline of Final Research Achievements

In order to specifically understand the effects of storm surges and tsunamis during periods of rising sea levels, this study examines the Idagawa lowland in Fukushima Prefecture where the effects of earthquake and tsunami have been known, and the Ganges-Brahmaputra-Meghna (GBM) Delta in Bangladesh. As a result, it was found that there are some sand layers in the Idagawa lowland that is thought to be affected by storm surges in warming stage. The storm surges have not reached the lowlands in the cooling stage. It was shown that storm surge deposits have increased in Bangladesh due to the rise in sea level during last 1000 years. Thus, it was shown that the land area is more susceptible to tsunamis and storm surges during the period of sea level rise due to global warming.

Free Research Field

堆積地質学

Academic Significance and Societal Importance of the Research Achievements

この研究によって，海水準上昇と津波，嵐の高潮が相互に働き，陸域への影響を大きくすることを示した．このことは温暖化が進むとされる現在，今までとは違った大きな災害をもたらす可能性を示したといえる．温暖化は，海水準上昇をもたらす．人類の多くが海岸付近で生活しており，嵐による高潮や地震による津波などの脅威にさらされている．これらの海面上昇と高潮や津波の相互作用による影響を過去の地層中に見出して，明らかにすることは，今後，地球温暖化の中での災害対策の基本として重要である．