Elucidation of the dynamic magma system by precise time-scale evaluation

为了了解火山岩浆动力系统，我们尝试发展新的年龄测定方法，并将其应用于天然火山喷出物。在此基础上，建立了多源ICP-MS U-Th-Ra不平衡测年方法，并确定了富士火山岩浆供给序列的持续时间。此外，我们研究了新的K-Ar测年相结合的加标和未加标的灵敏度方法，以确定喷发年龄小于0.1万年。这种方法可以成功地应用于印尼布拉坦火山的熔岩。建立了熔体浮力驱动的超火山喷发动力学模型。

In order to understand the dynamic magma system of volcanoes, we attempted to develop new age dating methods then applied them to natural volcanic ejecta. Consequently, we established new U-Th-Ra disequilibrium dating method by using multi collection ICP-MS, and determined the duration of magma supply sequences of Fuji volcano. Additionally, we examined new K-Ar dating combining the spiked and the unspiked sensitivity method to determine eruption ages less than 0.1 Myrs. This method could be successfully applied for lavas from Bratan volcano in Indonesia. The dynamic eruption model regarding supervolcan eruptions driven by melt buoyancy was established.