Computational simulations of volcanic eruptions and infrasound

火山喷发和次声的计算模拟

• 批准号: 1930979
• 负责人: Eric Dunham
• 金额: $ 20.05万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-15 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1930979&HistoricalAwards=false
• 关键词: Computational; simulations; volcanic; eruptions; infrasound

Volcanic eruptions generate sound waves in the atmosphere and seismic waves in the solid Earth. These waves can be recorded at a safe distance from volcanoes and used to constrain eruptive processes that are otherwise obscured from study. This project will develop computer simulations of magma ascent through volcanic conduits in the solid Earth and eruption into the atmosphere that also capture sound and seismic waves. Most current eruption simulations are based on simplifying approximations, like incompressible fluids and rigid solids, that eliminate waves. Simulation results from the project can be used to improve volcano monitoring, data interpretation, and hazard assessment. The project will provide training for a PhD student and postdoctoral scholar, and outreach activities for the general public include volcano-related demos at local elementary school science nights, STEMTaught articles for an elementary-school-level textbook meeting the Next Generation Science Standards, and a Stanford Ask A Scientist webpage.The eruption simulations will utilize a state-of-the-art aeroacoustics code originally designed to study sound radiation by turbulent jets and shocks created by discharge of high pressure gas from jet engines. The code will be modified to study volcanic eruptions by coupling to an unsteady conduit flow code that models the ascent, depressurization, and fragmentation of magma. Simulations of vulcanian and strombolian eruptions will be used to 1.) assess the validity of commonly used acoustic source models like the point monopole and linear acoustics; 2.) quantify the effects of turbulent entrainment on infrasound generation (facilitating joint interpretation of visual and infrasound data); and 3.) probe subsurface eruptive processes like the rate of depressurization of shallow reservoirs, providing insight into how gas and magma are temporarily stored, pressurized, and released near the vent; also, identify signatures of the descent of the fragmentation surface down the conduit in large vulcanian explosions. Seismic representation theory will be used to convert pressure and momentum changes within the conduit to equivalent seismic moment tensor and force sources in the elastic wave equation. Seismic constraints on eruptive processes like fragmentation will be derived to complement infrasound constraints. This project is supported by the Geophysics and Petrology/Geochemistry programs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

火山喷发在大气中产生声波，在固体地球中产生地震波。这些波可以在距火山安全距离处记录下来，并用于限制喷发过程，否则这些喷发过程将在研究中被掩盖。该项目将开发岩浆通过固体地球中的火山管道上升并喷发到大气中的计算机模拟，同时捕获声音和地震波。目前大多数喷发模拟都是基于简化的近似，例如不可压缩流体和刚性固体，可以消除波浪。该项目的模拟结果可用于改进火山监测、数据解释和灾害评估。该项目将为博士生和博士后学者提供培训，并为公众提供外展活动，包括在当地小学科学之夜进行与火山相关的演示、为符合下一代科学标准的小学教科书编写 STEM 教学文章，以及斯坦福大学询问科学家网页。喷发模拟将利用最先进的气动声学代码，最初设计用于研究湍流射流的声辐射和喷气发动机排出高压气体产生的冲击。该代码将被修改，通过耦合到模拟岩浆上升、减压和破碎的非稳态管道流代码来研究火山喷发。火山喷发和斯特龙博利喷发的模拟将用于 1.) 评估常用声源模型（如点单极子和线性声学）的有效性； 2.) 量化湍流夹带对次声产生的影响（促进视觉和次声数据的联合解释）； 3.) 探测地下喷发过程，例如浅层储层的减压速率，深入了解气体和岩浆如何在喷口附近暂时储存、加压和释放；此外，还可以识别大型火山爆炸中碎片表面沿着管道下降的特征。地震表示理论将用于将管道内的压力和动量变化转换为弹性波方程中的等效地震矩张量和力源。将导出对喷发过程（如碎裂）的地震约束，以补充次声约束。该项目得到了地球物理学和岩石学/地球化学项目的支持。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Infrasound Radiation from Impulsive Volcanic Eruptions: Nonlinear Aeroacoustic 2D Simulations

脉冲火山喷发的次声辐射：非线性气动声学二维模拟

• 发表时间: 2021
• 期刊: Journal of geophysical research
• 作者: Watson, Leighton M.;Dunham, Eric M.;Mohaddes, Danyal;Labahn, Jeff;Jaravel, Thomas;Ihme, Matthias
• 通讯作者: Ihme, Matthias

Ultra and Very Long Period Seismic Signatures of Unsteady Eruptions Predicted From Conduit Flow Models

根据管道流模型预测的不稳定喷发的超长周期地震特征

• DOI: 10.1029/2022jb024313
• 发表时间: 2022
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Coppess, Katherine R.;Dunham, Eric M.;Almquist, Martin
• 通讯作者: Almquist, Martin

Physics‐Based Model Reconciles Caldera Collapse Induced Static and Dynamic Ground Motion: Application to Kīlauea 2018

基于物理的模型协调了火山口塌陷引起的静态和动态地面运动：应用于 Kä«lauea 2018

• DOI: 10.1029/2021gl097440
• 发表时间: 2022
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Wang, Taiyi A.;Coppess, Katherine R.;Segall, Paul;Dunham, Eric M.;Ellsworth, William
• 通讯作者: Ellsworth, William