Volatile Degassing From Magma Chambers as a Control on Volcanic Eruptions
Volatile Degassing From Magma Chambers as a Control on Volcanic Eruptions
复制标题
岩浆房挥发物脱气控制火山喷发
DOI：
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
M. Richards
中科院分区：
文献类型：
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作者：
T. Mittal;M. Richards
岩浆储集层挥发分的损失会影响驱动地面变形和喷发的岩浆超压。尽管岩浆房周围的高温变质光环通常被认为具有低渗透性，但最近的理论、实验和野外研究都强调了岩浆系统中瞬时渗透率的作用。此外，直接测量表明，被动脱气是玄武岩和硅质火山总挥发分损失的重要组成部分。因此，当系统中存在岩浆时，地壳的有效渗透率可能比出土岩石样品的有效渗透率大许多个数量级。我们发展了一个完全耦合的孔热弹性框架来考虑挥发分的流动以及对地壳应力状态的相关影响，并计算了球面几何的解析解。然后，我们将岩浆箱模型与这些解结合起来分析岩浆系统中的喷发动力学。我们发现，除了粘性松弛、岩浆补给和冷却时间尺度外，孔压扩散时间尺度对地壳渗透率为10−17到10−19 m2的中等高渗透率的火山喷发起到一级控制作用。我们描述了一个参数空间，根据这些不同的时间尺度来识别哪些成分在不同的火山喷发区域中起主导作用。
The loss of volatiles from a magma reservoir affects the magmatic overpressure responsible for driving ground deformation and eruptions. Although the high‐temperature metamorphic aureole around a magma chamber is typically considered to have low permeability, recent theoretical, experimental, and field studies have highlighted the role of transient permeability in magmatic systems. Also, direct measurements suggest that passive degassing is a significant component of total volatile loss in both basaltic and silicic volcanoes. Consequently, the effective permeability of the crust when magma is present in the system can be many orders of magnitude larger than that of exhumed rock samples. We develop a fully coupled porothermoelastic framework to account for both the flow of volatiles as well as associated effects on the stress state of the crust and calculate an analytical solution for spherical geometry. We then combine a magma chamber box model with these solutions to analyze eruption dynamics in magmatic systems. We find that in addition to viscous relaxation, magma recharge, and cooling timescales, the pore pressure diffusion timescale exerts a first‐order control on volcanic eruptions with moderately high crustal permeabilities of order 10−17 to 10−19 m2. We describe a parameter space to identify which components dominate in different regimes for volcanic eruptions according to these different timescales.
影响因子：
18.3
作者：
Caricchi, Luca;Annen, Catherine;Pinel, Virginie
通讯作者：
Pinel, Virginie
DOI：
10.1098/rsta.2018.0298
发表时间：
2019-02-25
影响因子：
5
作者：
Edmonds, Marie;Cashman, Katharine V.;Jackson, Matthew D.
通讯作者：
Jackson, Matthew D.