[H-TT15] Development and application of environmental traceability methods

[HTT15-04] Comparative study of the granite weathering chemical characteristics of using ICP-MS

*kawagoe seiki¹, Yuki Kusakabe¹, Shiho Yabusaki² (1.Faculty of Symbiotic Systems science/Fukushima university, 2.Research institute for Humanity and Nature)

Keywords:ICP-MS, Granite, slope failure, weathering

In recent years, climate change has led to a series of record-breaking precipitation amounts in various parts of Japan, resulting in frequent and extensive disasters related to phenomena such as flooding and sediment production. Excessive sediment production is caused by slope failure. Slope failure is activated not only by precipitation, but also by topography and geological weathering. Therefore, to determine the risk of sediment production, not only hydrological quantities have to be taken into account, but also topographical and geological conditions. In this study, the weathering state of geological features, which is difficult to visualise in subsurface conditions, was quantified using chemical components. The chemical composition was determined by analysing river water samples from the geological distribution area. The chemical abundances were derived by determining the concentrations of multiple elements using ICP-MS and applying the hydrological abundances. The weathering degree should be derived for comprehensive geological conditions, but an attempt was made to derive the weathering degree for granite, which has a well-defined rock composition and a good track record of slope failures.