Abstract
We aimed to propose a combined simulation model of lahar triggered by snowmelt and examined effects of erupted sediment and snow in northwest of Mt. Yake, central Japan. By composing three models (one dimensional heat transfer and snowmelt model, drainage model of snowmelt water in source area, and two dimensional lahar model), we could simulate not only inundation and changes in ground level due to lahar but their timings. Supply of erupted sediment on snow layer caused exponential decreases in thickness of snow layer and very high initial peak of snowmelt water. Although volume of snowmelt water was sufficient, snowmelt water drained from the source area (= initial lahar) was very small under conditions in which snow layer partially remained after snowmelt process.
