Magma Waves, magma wagging and volcanic oscillations

岩浆波、岩浆摇摆和火山振荡

• 批准号: 1645057
• 负责人: David Bercovici
• 金额: $ 54.3万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1645057&HistoricalAwards=false
• 关键词: Magma; Waves; magma; wagging; volcanic

Volcanoes are dynamic and display a wide range of activity even before they erupt. Many volcanoes, especially the most destructive ones, undergo long slow oscillations in ground swelling, gas emissions and seismic activity, with periods between repeated peak activity of hours to days. Volcanoes may also experience tremor or shaking with much shorter periods of around one second. Such oscillations, with both day- and second-long periods, can last for weeks before an eruption occurs, and thus serve as important precursors to volcanic disasters. Understanding the cause for these oscillations is therefore critical for forecasting these disasters as well as for advancing the science of how volcanoes work. This project seeks to unify two leading physical models for both the slow ultra-long, i.e., day-long, period oscillations and volcanic tremor, with second-long oscillation periods. Our model explains long-period oscillations in terms of slowly ascending magma waves of gas pulses in the magma-filled volcanic conduit, which arrive sequentially at the surface, causing ground swelling and other activity such as small earthquakes. The shorter-period tremors are explained by a magma wagging mechanism in which the heavy column of magma in the volcanic conduit wags side-to-side inside of a spongy jacket of extra-bubbly magma. However, very-long and shorter period oscillations are not independent of each other; for example, long period oscillations involve cycles of enhanced volcanic tremor activity. The main goal of this project is to develop a 3-D (three-dimensional) model of bubbly magma in a volcanic conduit to account for the full range of oscillatory behavior, from rapid tremor to ultra-slow cycles. The central hypothesis of this study is that the evolution of magma waves in 3-D influences the onset of magma-wagging motion; this potentially provides a prediction for how long-period oscillations evolve and trigger (and sustain) shorter-period volcanic tremor prior to an eruption. The project also involves development of fundamental theories of two-phase physics that will, in addition to its impact on volcanic hazards, may contribute to better understanding of other problems of geological, environmental and energy-related processes.The models of magma waves and magma wagging are built from the same physics of two-phase systems,; the processes these models describe are inevitably coupled and influence each other's behavior. For example, degassing activity during long period cycles correlates with tremor, and our models suggest that gas emissions help drive tremor activity. Moreover, the current magma-wave model accounts for only vertical motion in one dimension, while the present magma-wagging model treats only horizontal movement in one-dimension. However, new preliminary models already suggest that the magma wagging entails circular swirling motion that can be detected from seismic stations. Magma waves are also likely to develop three-dimensional shapes, like spherical pockets near the center of the volcanic conduit, or stretched out bands near the conduit wall; these wave shapes would then affect how the magma column wags side to side. Accordingly, the primary activity of this proposal is to (1) develop the 3-D two-phase analytic theories of magma waves and magma wagging, including new physics such as gas exsolution and variable viscosity; (2) develop a 3-D unified numerical model of fully coupled magma wave and wagging evolution and activity; and (3) test the model predictions against new laboratory experiments, as well as existing seismological, ground-motion and gas-flux data, including recent observations from a pilot project in a volcano in Mexico. The goal of this work is to provide physical understanding and, ideally, model forecasting with a unified theory for the cause and evolution of long and short period oscillations, leading up to explosive volcanic eruptions. The magma wave and magma wagging models form the essential building blocks for a complete model of long and shorter period oscillations prior to volcanic eruption. The extension of these models into three-dimensions with more sophisticated physics, and their eventual unification into a single numerical model, will provide a wealth of predictions to further test the model with lab experiments as well as existing and new data. The model will provide insight into the dynamics and evolution of the volcanic magma column prior to an eruption, as well as a potentially important prognostic tool for volcanic hazards.

火山是动态的，甚至在爆发之前就显示出广泛的活动。许多火山，特别是最具破坏性的火山，在地面膨胀、气体排放和地震活动中经历长时间的缓慢振荡，在几小时到几天的重复高峰活动之间。火山也可能经历震颤或摇晃，时间短得多，约为一秒。这种振荡，有一天和一秒长的周期，在火山爆发之前可以持续数周，因此是火山灾害的重要前兆。因此，了解这些振荡的原因对于预测这些灾害以及推进火山如何工作的科学至关重要。该项目旨在统一两个领先的物理模型，用于慢速超长，即，一天的周期振荡和火山震颤，第二长的振荡周期。我们的模型解释了长周期振荡，在充满岩浆的火山管道中缓慢上升的气体脉冲岩浆波，依次到达地表，引起地面膨胀和其他活动，如小地震。较短周期的震动是由岩浆摇摆机制解释的，在这种机制中，火山管道中的重岩浆柱在泡沫状岩浆的海绵状外套内左右摇摆。然而，非常长和较短的周期振荡并不是相互独立的;例如，长周期振荡涉及增强的火山震颤活动的周期。该项目的主要目标是开发一个火山管道中气泡岩浆的3-D（三维）模型，以解释从快速震颤到超慢周期的全方位振荡行为。这项研究的中心假设是，在3-D的岩浆波的演变影响岩浆摆动运动的开始，这可能提供了一个预测如何长期振荡的演变和触发（和维持）较短的火山喷发前的震颤。该项目还涉及发展两相物理学的基础理论，除了对火山灾害的影响外，还可能有助于更好地理解地质、环境和能源相关过程的其他问题。岩浆波和岩浆摇摆的模型是根据两相系统的相同物理学建立的;这些模型描述的过程不可避免地相互耦合并影响彼此的行为。例如，在长周期循环期间的脱气活动与震颤相关，我们的模型表明气体排放有助于驱动震颤活动。此外，目前的岩浆波动模型只考虑了一维的垂直运动，而目前的岩浆摆动模型只考虑了一维的水平运动。然而，新的初步模型已经表明，岩浆摇摆需要圆形漩涡运动，可以从地震站检测到。岩浆波也可能发展成三维形状，比如火山管道中心附近的球形口袋，或者管道壁附近的延伸带;这些波浪形状将影响岩浆柱左右摇摆的方式。因此，本项目的主要工作是：（1）发展岩浆波动和岩浆摆动的三维两相解析理论，包括气体出溶和变粘度等新物理，（2）发展完全耦合的岩浆波动和摆动演化与活动的三维统一数值模型，（3）建立岩浆波动和岩浆摆动演化与活动的三维统一数值模型，（4）建立岩浆波动和岩浆摆动演化与活动的三维统一数值模型。（3）用新的实验室实验以及现有的地震学、地面运动和气体通量数据（包括最近在墨西哥火山试验项目中的观测结果）来检验模型预测。这项工作的目标是提供物理上的理解，理想情况下，模型预测与长期和短期振荡的原因和演变的统一理论，导致爆炸性火山爆发。岩浆波和岩浆摇摆模型形成了火山爆发前长周期和短周期振荡的完整模型的基本组成部分。将这些模型扩展到具有更复杂物理学的三维空间，并最终将其统一为单个数值模型，将提供丰富的预测，以进一步用实验室实验以及现有和新的数据来测试模型。该模型将提供对火山喷发前火山岩浆柱的动态和演变的深入了解，以及对火山灾害的潜在重要预测工具。

项目成果

Granular size segregation in silos with and without inserts

带或不带插入件的筒仓中的粒度分离

• DOI: 10.1098/rspa.2020.0242
• 发表时间: 2021
• 期刊: Physical and Engineering Sciences
• 作者: Cliff, A.;Fullard, L. A.;Breard, E. C.;Dufek, J.;Davies, C. E.
• 通讯作者: Davies, C. E.

An experimental study of volcanic tremor driven by magma wagging

岩浆摆动驱动的火山震颤实验研究

• DOI: 10.1093/gji/ggab404
• 发表时间: 2021
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: Dehghanniri, Vahid;Jellinek, A. Mark
• 通讯作者: Jellinek, A. Mark

Microphysical Effects of Water Content and Temperature on the Triboelectrification of Volcanic Ash on Long Time Scales

• DOI: 10.1029/2019jd031498
• 发表时间: 2019-08
• 期刊: Journal of Geophysical Research: Atmospheres
• 作者: Joshua Méndez Harper-Joshua-Méndez Harper-2126679743;L. Courtland;J. Dufek;J. McAdams

Inferring Compressible Fluid Dynamics From Vent Discharges During Volcanic Eruptions

• DOI: 10.1029/2018gl078286
• 发表时间: 2018-07-28
• 期刊: GEOPHYSICAL RESEARCH LETTERS
• 影响因子: 5.2
• 作者: Harper, J. S. Mendez;Cimarelli, C.;Thomas, R. J.
• 通讯作者: Thomas, R. J.

The Effects of Degassing on Magmatic Gas Waves and Long Period Eruptive Precursors at Silicic Volcanoes

脱气对硅质火山岩浆气波和长周期喷发前兆的影响

• DOI: 10.1029/2020jb019755
• 发表时间: 2020
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Jordan, Jacob S.;Bercovici, David;Liao, Yang;Michaut, Chloé
• 通讯作者: Michaut, Chloé