Mechanism of Emplacement of Large Volume Pyroclastic Flows: ITO Ignimbrite, Japan

本项目旨在研究火山碎屑流如何穿越高山（1000米）：（1）它们是否是扩展流并分离成不同的部分，或（2）具有高动量的非扩展流，它们在山上移动，就像在平地上一样。了解流动机制如何影响跳动长度和海拔高度的流动可以超越的危害评估的主要后果。伊藤熔结凝灰岩是理想的研究对象：它（1）跨越高山，（2）暴露良好且广泛，（3）容易进入。流动方向的差异，识别不同的流动模式的关键，将通过标准的地质方法（相分析，最大碎片尺寸的分布，组构分析）和磁化率的各向异性测量。研究结果不仅可以提供对火山碎屑流运动的更好的科学认识，而且还可以引发与拯救人类生命直接相关的行政行动。

This project is to study how pyroclastic flows cross high mountains (1000m): whether (1) they are expanded flows and segregate into different parts, or (2) non-expanded flows with high momentum that move over mountains as they do on flat ground. Understanding how flow mechanisms influence runout length and elevations a flow can surmount has major consequences for hazard assessments. The Ito ignimbrite is ideal to study: it (1) crosses high mountains, (2) is well exposed and extensive, and (3) access is easy. Flow direction differences, critical for recognition of the different flow models, will be measured by standard geologic methods (facies analysis, distribution of maximum fragment sizes, fabric analysis) and by anisotropy of magnetic susceptibility. Results should not only provide a better scientific understanding of pyroclastic flow movement, but could also trigger administrative action directly related to saving human lives.