OHMORI Hiroo Graduate School of Science, the University of Tokyo, Professor, 大学院・理学系研究科, 教授 (60092160)
MATSUMOTO Jun Graduate School of Science, the University of Tokyo, Associate Professor, 大学院・理学系研究科, 助教授 (80165894)
SAITO Kyoji Faculty of Education, Saitama University, Associate Professor, 教育学部, 助教授 (60170495)
|Budget Amount *help
¥4,000,000 (Direct Cost : ¥4,000,000)
Fiscal Year 1995 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1994 : ¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1993 : ¥1,700,000 (Direct Cost : ¥1,700,000)
A large slope failure with a volume of 34 million cubic meters took place at Ontakesan, Japan, in Sept.1984. The volume of the failure is the eighth largest among historical large slope failures in Japan. The sediments produced by the failure went down along the valley of the Otaki river, and were deposited in the middle reach. Subsequently the deposits were incised to reproduce sediments which have been transported downstream. This slope failure and subsequent geomorphic changes provide a good example to analyze the development of fluvial landforms and changes in hydrological processes after big slope failures. For this reason, synthetic research were performed in the drainage basin of the Otaki river.
Our research focuses mainly on five issues : a) change in channel forms, b) transportation of river sediments, c) rates of erosion and deposition, d) development of terrace scarps and valley forms, and e) change in river runoff. Related issues such as geology, climate, and vegetation in the river basin were also examined. To cover such broad scientific fields, researchers with experiences and knowledge in various fields took part in the group. Some of the members had already worked in the Otaki river basin before the group foundation. The preceding research data were also used in this study. As a result, some new insights were obtained regarding geomorphology, sedimentology, hydrology, climate, and vegetation in the river basin. This publishing report contains ten papers to present our results.
Furthermore, our group performed research in other areas of Japan to improve the understanding of fluvial geomorphology, slope failure, river runoff, clinate, and vegetation. Although the results of these studies are not included in this report, they were presented in journals, scientific reports, and conferences. The list of these papers is carried in this report.