Assessment of the liquefaction vulnerability caused by the artificial land modification

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K01224
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Geography
• Research Institution: Gunma University
• Principal Investigator: Aoyama Masafumi 群馬大学, 教育学部, 准教授 (30724744)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 液状化危険度評価 / 土地履歴 / 砂利採掘 / 谷埋め盛土 / 史料 / 2011年東北地方太平洋沖地震 / 2016年熊本地震 / 2018年北海道胆振東部地震

Outline of Final Research Achievements

The land condition and land history of the liquefied area due to the recent earthquake were clarified. There were many areas located on the past gravel pits in the area that was considered to be the liquefaction occurrence in the natural ground of the 2011 Tohoku Earthquake. It was suggested that small rivers or waterways existed until the Edo period in the zonal liquefaction concentrated area that appeared during the 2016 Kumamoto earthquake. The liquefaction occurrence area in Kiyota Ward, Sapporo City, during the 2018 Hokkaido Eastern Iburi Earthquake was the valley embankment area that was created in the hilly area since the 1980s. Most of the liquefaction areas caused by recent earthquakes have a history of artificial land modification, and the liquefaction vulnerability of artificial ground such as buried soil in river and valley topography and backfill soil in mined areas is high.

Free Research Field

自然地理学

Academic Significance and Societal Importance of the Research Achievements

多くの人々の生活の場となっている平野部の海、河川、谷地形や採掘地などの埋立地は液状化脆弱性が高いことが知られていたが、土地履歴の調査がこれまで不十分であり、それらの領域が十分に抽出されていなかった（適切にハザードマップに反映されていなかった）ことを本研究により示すことができた。本研究で実施した多角的・統合的な調査・検討によって近年の地震による液状化域の土地履歴を明らかにできたことは、今後の液状化危険度の高い領域の抽出や液状化被害の軽減につながることから、その意義は大きい。