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(1000米)：(1)它们是扩张流并分离成不同的部分，还是(2)像在平地上那样在山上移动的具有高动量的非扩张流。了解水流机制如何影响径流可以跨越的长度和高程，对危险评估具有重大影响。伊藤岩是理想的研究对象：(1)跨越高山，(2)裸露良好，范围广泛，(3)容易接近。对于识别不同的流动模式至关重要的流动方向差异将通过标准地质方法(相分析、最大碎块尺寸分布、组构分析)和磁化率的各向异性来测量。这些结果不仅应该提供对火山碎屑流运动的更好的科学理解，而且还可能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.