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Classification of rivers based on fluvial land forms and debris transport processes in Yaku Island, southern Japan.

日本南部屋久岛基于河流地貌和泥石流迁移过程的河流分类。

基本信息

批准号：
15500691
负责人：
SHIMAZU Hiroshi
金额：
$ 0.96万
依托单位：
Rissho University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15500691/
关键词：
mountain river debris transport process relief condition DEM drainage system debris flow landslicle dam Yaku Island 河床堆積物崩壊

项目摘要

Based on morphometric analysis and field survey, the relief condition, debris production and transport processes of Yaku Island, Southern Japan are discussed. Mean altitude and mean relief derived from Japanese mountains show a strong positive relationship. The highest point on Yaku Island plots near this regression line indicating that the relief of the island is high enough for its altitude. The relief in the central area of Yaku Island, which is the area with the highest altitude, is lower than in other regions. Yaku Island has very high relief in lower altitude areas and very low relief in higher altitude areas. In the high relief areas of the coast, there are deep valleys with steep slopes. In the low relief areas of the central part of the island, low relief surfaces are distributed on the ridges. In the upper-middle reaches through the large relief area, huge gravels, whose maximum diameters are 3-10m, fill on the riverbed. Gradual downstream decrease of maximum diameter according to the decrease of channel slope shows that these huge gravels were transported being affected by sorting process. There are many landslide scars in the tributaries which join the main stream in these reaches. At the junctions these tributaries develop alluvial cones on the valley floor of the main stream. The deposits of the riverbed and the alluvial cones include several meters size gravels. The distinctive relief conditions of Yaku Island can be attributed to the uplift characteristics of the island. Huge block production owes to the geological characteristics. These blocks sometimes formed landslide dams at the tributary junctions with the main stream. Large debris flows or torrential floods, caused by landslides in the tributary heads or burst of the dams, transported such huge gravels.

通过地貌分析和野外考察，探讨了日本南部屋久岛的地形地貌、岩屑产生和搬运过程。来自日本山脉的平均海拔和平均起伏度显示出很强的正相关关系。Yaku岛上的最高点在这条回归线附近，表明该岛的地形相对于其海拔高度足够高。雅库岛中部地区是海拔最高的地区，地势低于其他地区。Yaku岛在低海拔地区地形起伏很大，在高海拔地区地形起伏很小。在海岸的高起伏地区，有陡峭的山谷。在岛中部的低起伏区，低起伏面分布在山脊上。在上中游通过大面积的地形起伏，河床上堆积着最大粒径为3- 10 m的巨砾。最大粒径随河道坡度的减小而向下游逐渐减小，表明这些巨砾的搬运受到分选作用的影响。在这些河段汇入干流的支流中有许多滑坡痕迹。在交汇处，这些支流在干流的谷底形成冲积锥。河床和冲积锥的沉积物包括数米大小的砾石。雅库岛独特的地形条件可以归因于该岛的隆起特征。大区块开采是地质特征决定的。这些块体有时在支流与干流的交汇处形成滑坡坝。由于支流源头滑坡或大坝决堤而引起的大规模泥石流或山洪，运送了如此巨大的砾石。