| Budget Amount *help |
¥16,640,000 (Direct Cost: ¥12,800,000、Indirect Cost: ¥3,840,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2019: ¥6,760,000 (Direct Cost: ¥5,200,000、Indirect Cost: ¥1,560,000)
Fiscal Year 2018: ¥6,890,000 (Direct Cost: ¥5,300,000、Indirect Cost: ¥1,590,000)
Fiscal Year 2017: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Outline of Final Research Achievements |
During explosive volcanic eruptions, a mixture of pyroclasts and gas is ejected from the volcanic vent, and can flow on the ground surface as a pyroclastic density current (PDC). PDCs are generally stratified with respect to particle concentration and are composed of two layers: the upper dilute layer and the lower dense layer. The dynamics of these two layers are controlled by various physical processes with different length scales. The upper dilute layer is affected by particle settling, thermal expansion of entrained air, and resistance at the flow front, whereas the lower dense layer is controlled by friction, deposition, and erosion at the base.
We developed a two-layer PDC model where an eruption-cloud model is applied to the upper dilute layer and a depth-averaged model to the lower dense layer. The new model enables us to investigate the complex effects of volcanological factors (e.g., topographic effects as well as eruption conditions) on the run-out distances of PDCs.
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