| Project/Area Number |
17K18415
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Geology
Stratigraphy/Paleontology
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| Research Institution | National Institute of Advanced Industrial Science and Technology |
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Principal Investigator |
Utsunomiya Masayuki 国立研究開発法人産業技術総合研究所, 地質調査総合センター, 主任研究員 (10738313)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2017: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
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| Keywords | 海底地すべり / 前弧海盆 / 不整合 / 新生代 / 石灰質ナノ化石 / テフラ / 南関東 |
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| Outline of Final Research Achievements |
Mass-transport deposit (MTD)s in the upper Cenozoic forearc basin fills in the Southern Kanto area, central Japan, were examined to understand relationship between submarine landslides and tectonic/sedimentation processes resulting in unconformity. MTDs are intercalated not only on the unconformity but also in the other horizons. Based on stratigraphic position, lateral distribution, internal structure, tephra beds and calcareous nannofossil in MTDs, the formation ages and erosion/deposition processes were clarified. Deep-seated submarine landslides would have occurred after formation of thick muddy deposits. In addition, tephra bed would make a significant role in preferential formation of slide plane.
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| Academic Significance and Societal Importance of the Research Achievements |
海底地すべりは陸上のものと比べ大規模で，油ガス田などの海上設備の破壊や津波を引き起こすことから，社会経済に少なからぬ打撃を与える．その直接的な発生要因と共に，長期的な条件として土砂の堆積速度や構造運動による斜面傾動の影響が重要視されている．南関東の前弧海盆堆積物は第四紀の高精度な年代指標を用いて不整合や海底地すべりの形成年代を制約出来ることに加えて，こうした長期的な発生要因を理解するための地質学的検討が可能である．研究の結果，海底地すべりの特徴や海盆発達との関係を地質学的証拠に基づいて理解し，活動的な前弧域における海底斜面の長期的な安定性を理解する上で意義ある成果が得られた．
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