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

大体积火山碎屑流的侵位机制：ITO Ignimbrite，日本

• 批准号: 9205022
• 负责人: Richard Fisher
• 金额: --
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-01 至 1995-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9205022&HistoricalAwards=false
• 关键词: Mechanism; Emplacement; Large; Volume; Pyroclastic

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.

该项目旨在研究火山碎屑流如何穿越高山（1000m）：是否（1）它们是膨胀流并分离成不同的部分，还是（2）具有高动量的非膨胀流，像在平地上一样越过山脉。了解流动机制如何影响流动长度和流动可以克服的高度对于危险评估具有重大影响。伊东熔凝岩非常适合研究：它 (1) 跨越高山，(2) 暴露良好且面积广阔，(3) 交通方便。流向差异对于识别不同的流动模型至关重要，将通过标准地质方法（相分析、最大碎片尺寸分布、组构分析）和磁化率各向异性来测量。结果不仅应该提供对火山碎屑流运动的更好的科学理解，而且还可以触发与拯救人类生命直接相关的行政行动。