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

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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.