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Prediction of Sediment Yield by Shallow Landslide Based on Landslide Periodicity

基于滑坡周期的浅层滑坡产沙量预测

基本信息

批准号：
01560172
负责人：
SHIMOKAWA Etsuro
金额：
$ 1.66万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01560172/
关键词：
Landslide Landslide periodicity Sediment yield Prediction Topsoil Granite Shirasu (Ito pyroclastic flow deposits)rainfall

项目摘要

The purpose of this study is to develop a new method for prediction of sediment Yield by shallow landslide based on landslide periodicity. The main research areas are Mt. Shibisan, Yaku-Aina island, Mt. lichifusa-yama, Kagoshima-shi(Shirasu)and Aso-Nekodake, Southern Kyushu, Japan. Landslide scars were made out by interpretation of aerophotographs and field survey and topsoil thickness on the slopes was wmured using a cone-tipped metal stick in the research sites.1. Many landslide sears with different ages distribute at the 0-order basins in each research area according to the landslide chronological sap. Although the greater part of scars has been formed on different slope site each other, in the volcanic research areas the newer and older scars overlap on a same slope site during less than 100 years.2. The topsoil on the steep slope has a critical thickness for shallow landsliding beyond which the tpsoil can not grow up largely. The critical-thickness depends on geological and topographical setting of the slopes.3. The frequency of landslide in the forested basins depends on the landslide periodicity as well as rainfall if other factors are same.4. The shallow landslide potential in a forested basin is expressed by probability density function of the topsoil thickness. The probability function is time dependence. If many shallow landslides occur under a heavy rain, the density of topsoil thickness more than critical one is reduced and as a result of that the landslide potential falls off. On the contrary if the landslide does not occur during a long period, the density of topsoil thickness more than critical one increases and as a result of that the landslide potential rises.

本研究的目的是发展一种基于滑坡周期性的浅层滑坡产沙预测新方法。主要研究领域是Mt。Shibisan，Yaku-Aina island，Mt. lichifusa-yama，Kagoshima-shi（Shirasu）and Aso-Nekodake，Southern Kyushu，Japan.通过航片解译和野外调查，对滑坡痕迹进行了提取，并在研究现场用锥形金属棒测量了边坡表土厚度.根据滑坡年代学资料，在各研究区的0级盆地中分布着许多不同时代的滑坡遗迹。虽然绝大部分的火山遗迹都是在不同的坡位上相互形成的，但在火山研究区，同一坡位上的新老遗迹在不到100年的时间里相互重叠.陡坡表土存在一个发生浅层滑坡的临界厚度，超过该厚度表土不能大面积上长。临界厚度取决于边坡的地质和地形条件.在其他因素相同的情况下，森林流域滑坡的发生频率取决于滑坡的周期性和降雨量.森林盆地浅层滑坡潜势可用表土厚度的概率密度函数表示。概率函数是时间依赖性的。如果在大雨下发生多处浅层滑坡，则超过临界厚度的表土密度会降低，从而导致福尔斯滑坡潜力下降。反之，如果滑坡长期不发生，则超过临界厚度的表土密度增加，滑坡潜势增大。