地形発達効果および気候変動を考慮した斜面危険度の広域評価

随着我们的环境变得越来越温暖，极端气候变得更加频繁。全球气候变暖直接或间接地影响着坡面植被、地形地貌和稳定性，而这些是坡面灾害发生的主导因素。滑坡是各种边坡灾害的成因，进行边坡灾害评价，其分析对象是滑坡。本研究旨在发展一种方法，可以实现高分辨率的预测气候变化影响下的斜坡灾害。在过去两年，我们成功地完成了一个新的基于力学的滑坡模型的发展，以确定三维不稳定区容易发生滑坡的不规则表土层陡峭和植被山坡上使用孔隙弹性，摩尔-库仑破坏理论和树异速生长。2014年7月发生在日本广岛和2011年7月发生在韩国首尔的两个历史事件被用于验证和案例研究。模拟结果与真实的现场情况吻合较好。在三维地下水模拟方面，通过对地下水水力学理论的分析研究，提出了一种新的正确模拟方法，并采用松弛法对三维不规则土层中地下水位的演化进行了数值模拟。将两种模型进行集成，实现了高分辨率的三维滑坡预测。然而，景观演化模拟部分仍在发展中，并将在不久的将来出现，长期气候变化影响下的山坡过程的综合模拟。

As our environment becomes warmer, extreme climate becomes more frequent. Global warming directly or indirectly influences hillslope vegetation, landform and stability, which are the dominant factors for hazard occurrence on slopeland. To perform slopeland hazard assessment, the analysis target is landslide which is the origin of all kinds of slopeland hazards. This research aims to develop a methodology which can achieve high resolution prediction of slopeland hazards under climate change impact. In last two years, we have successfully finished the development of a novel mechanically based landslide model to identify three-dimensional unstable zones prone to landslide in irregular topsoil layers on steep and vegetated hillslopes by using Poroelasticity, Mohr-Coulomb failure theory and tree allometry. Two historical events occurred in Hiroshima, Japan in July 2014 and in Seoul, Korea in July 2011 are used for verification and case studies. The simulated results are in good agreements with real field conditions. For 3D groundwater modeling, we successfully analytically investigate hydraulic groundwater theory to propose a new way for correct modeling, and perform numerical modeling of groundwater table evolution in irregular 3D soil layer using relaxation approach. Both of the models above have been integrated to achieve 3D landslide prediction in the high resolution. However, the part for landscape evolution simulation is still under development, and to be appear in the near future for comprehensive modeling of hillslope process under long-term climate change influence.