Collaborative Proposal: Experimental Studies of Dilute Pyroclastic Density Currents

合作提案：稀火山碎屑密度流的实验研究

• 批准号: 1447559
• 负责人: Michael Manga
• 金额: $ 23.21万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-15 至 2019-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1447559&HistoricalAwards=false
• 关键词: Collaborative; Proposal; Experimental; Studies; Dilute

Pyroclastic density currents are hot and fast-moving mixtures of solid particles and gas produced by explosive volcanic eruptions or the collapse of lava domes. They travel great distances, pose substantial hazards, and alter landscapes. The processes governing the movement of, and transport in, pyroclastic density currents are not well understood quantitatively. Even conceptual models remain controversial. Basic questions remain about how hills, ridges, and valleys alter and direct pyroclastic density currents and about how air mixes into the currents. These key processes control current speed, direction, and injection of ash into the atmosphere. The long term outcome of better understanding pyroclastic density currents is a scientific foundation for assessing the hazards they pose.This project will use dynamically scaled laboratory experiments, in particular their interaction with topography, to understand pyroclastic density current dynamics. This will be accomplished by imaging the three-dimensional velocity and concentration fields inside modeled dilute pyroclastic density currents, and quantifying the entrainment of air and sedimentation of particles. This understanding will improve our ability to relate field deposits to the dynamics of these currents. The experimental setup is designed to permit a large number of experiments and hence to explore relationships between parameters and processes.

火山碎屑密度电流是由爆炸性火山喷发或熔岩圆顶崩溃产生的固体颗粒和气体的热和快速的混合物。他们走得很大，构成了重大危害并改变了景观。在定量上尚未很好地理解了控制火山碎屑密度电流和运输的过程。甚至概念模型仍然存在争议。关于山丘，山脊和山谷如何改变和直接的火山碎屑密度电流以及空气如何混合到电流的基本问题。这些关键过程控制当前的速度，方向和将灰分注入大气中。更好地理解火山碎屑密度电流的长期结局是评估其构成危害的科学基础。该项目将使用动态缩放的实验室实验，特别是它们与地形的相互作用，以了解Pyroclastic Montivers Proverty Dynamics。这将通过对建模稀释的火山塑性密度电流内部的三维速度和浓度场进行成像，并量化空气的夹带和颗粒沉积。这种理解将提高我们将现场沉积与这些电流动态联系起来的能力。实验设置旨在允许大量实验，因此可以探索参数和过程之间的关系。