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

这个项目是研究火山碎屑流如何穿越高山（1000m）：是(1)膨胀流并分离成不同的部分，还是(2)非膨胀流，动量大，像在平地上一样在山上移动。了解流动机制如何影响跳动长度和流动可以超越的高度，对危害评估具有重要意义。伊藤褐煤是理想的研究对象：它(1)跨越高山，(2)暴露良好且分布广泛，(3)进入容易。流动方向差异是识别不同流动模型的关键，将通过标准地质方法（相分析、最大碎片尺寸分布、结构分析）和磁化率的各向异性来测量。研究结果不仅可以为火山碎屑流运动提供更好的科学认识，而且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.