2022 Fiscal Year Final Research Report
Study on slope deformation caused by crustal movement and climatic change along high relief collision belt in sub-troptical zone
| Project/Area Number |
19H01368
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 04010:Geography-related
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| Research Institution | Yamagata University |
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Principal Investigator |
YAGI HIROSHI 山形大学, 地域教育文化学部, 名誉教授 (40292403)
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| Co-Investigator(Kenkyū-buntansha) |
下岡 順直 立正大学, 地球環境科学部, 准教授 (10418783)
鄒 青穎 弘前大学, 農学生命科学部, 講師 (40750055)
佐藤 浩 日本大学, 文理学部, 教授 (60360468)
熊原 康博 広島大学, 人間社会科学研究科(教), 准教授 (60379857)
若井 明彦 群馬大学, 大学院理工学府, 教授 (90292622)
松四 雄騎 京都大学, 防災研究所, 准教授 (90596438)
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| Project Period (FY) |
2019-04-01 – 2023-03-31
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| Keywords | 地すべり / 地すべりダム / 突然決壊 / 土石流 / 長距離移動 / 高ヒマラヤ |
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| Outline of Final Research Achievements |
Higher terrace surfaces composed of vast deposits up to 200 meters in thickness which sometimes embed debris flow deposits in origin are distributed along Marsyandhi river and other valleys transversing the Himalayan ranges. The debris deposits intercalate gneiss boulders are found even in 40 Kilometers lower course from the piedmont of the Higher Himalayas. Emergence of the higher terraces are dated back to late Last Glacial Age, 40ka to 20ka. Those implies debris flow came from the Higher Himalayas due to glaciation and rock slope failures in the Last Glacial Age. Lower terrace of 4ka developed along the Marsyandhi river also is composed of debris flow deposits including gneiss boulders traveled long distance. There remain many traces of landslides and debris flow deposits of the Holocene age along Marsyandhi valley indicate that landslide damming and subsequent outbursts of dam lakes occurred and debris flow traveled for long distance.
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| Free Research Field |
地形学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究はヒマラヤなどの高起伏地域ので気候変化や地震活動を誘因とするカタストロフィックな地形変化を数万年から数千年の時間オーダーで捉えたものである．そして，山体崩壊が河道閉塞と決壊を繰り返しながら，土石流に変化して数10kmを流下してきたことを明らかにした．その類似現象が小規模でながらば現代でも発生していることから，幾つかの条件が揃えば現在でも決して発生し得ないものではないことを明らかに出来たと考える．この知見は，災害回避に繋がる村落開発や都市開発に活用されることが望まれる．
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