1990 Fiscal Year Final Research Report Summary
Earth Surface Movement Inferred from Grain-size Variation in Pond Sediments
| Project/Area Number |
01540341
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
気象・海洋・陸水学
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| Research Institution | The Graduate School of Science and Technology, Kobe University |
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Principal Investigator |
KASHIWAYA Kenji The Graduate School of Science and Technology, Kobe University Assistant Professor, 大学院・自然科学研究科, 助手 (30161029)
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| Co-Investigator(Kenkyū-buntansha) |
ISOZUMI Yasuto Chemical Institute, Kyoto University Associate Professor, 化学研究所, 助教授 (50027603)
OKIMURA Takashi Faculty of Engineering, Kobe University Associate Professor, 工学部, 助教授 (50031125)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Mass movement / Man-made landform / Pond sediment / Grain size / Heavy rainfall |
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| Research Abstract |
Grain-size analysis of pond sediments in the Rokko Mountains shows that years of heavy rainfalls can traced in the grain-size sequences for the past 50 years. These years show up as prominent coarsenings in the grain-size distribution. This coarse layer was used to cross date undated sediment to dated sediment in the heavy rainfall area in the mountains. Sediment from a pond somewhat distant from the area was cross-dated to sediment in the mountain pond by the use of peak values of ^<137>Cs data. Changes in grain-size distribution show differences in the erosional and sedimentary environments of the ponds in the mountain area and in the area just to the west of the mountains ; prominent coarsening severe heavy rainfall area and non prominent coarsening in less heavy rainfall areas that are correlated with rainfall distribution in times of heavy rain. These results show that grain-size analysis can provide a very useful tool for reconstructing the erosional environments during the past 10^1-10^2 years.
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