Bayesian inversion of data from effusive volcanic eruptions using physics‐based models: Application to Mount St. Helens 2004–2008
Bayesian inversion of data from effusive volcanic eruptions using physics‐based models: Application to Mount St. Helens 2004–2008
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使用基于物理的模型对火山喷发数据进行贝叶斯反演：2004-2008 年圣海伦斯火山的应用
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
P. Segall
中科院分区：
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作者：
K. Anderson;P. Segall
基于物理的火山喷发模型可以直接将岩浆过程与多种时变的地球物理观测结果联系起来，并且当在逆过程中使用时，可以将所有可用信息用于估计火山系统的性质。我们开发了一种技术，用于反演大地测量、喷出通量和其他类型的数据，使用基于物理的喷涌硅火山喷发模型来估计岩浆房的几何形状、压力、深度和挥发性含量，以及连接岩浆房与地表的管道的特性。贝叶斯反公式可以很容易地将独立信息合并到反演中，例如对熔融水含量的岩石学估计，并产生对模型参数和火山其他属性的概率估计。使用马尔科夫链蒙特卡罗算法对概率分布进行采样。我们使用GPS和2004-2008年圣海伦火山喷发的挤压数据来应用这项技术。与更传统的反演（如将大地测量数据单独与运动学正演模型相结合）相比，这种技术能够提供岩浆特性的约束，包括其挥发性含量，以及岩浆室的绝对体积和压力。研究结果表明，大腔体面积约为40km3，形心深度为11 ~ 18 km，腔体顶部溶解水含量为2.6 ~ 4.9 wt%。
Physics‐based models of volcanic eruptions can directly link magmatic processes with diverse, time‐varying geophysical observations, and when used in an inverse procedure make it possible to bring all available information to bear on estimating properties of the volcanic system. We develop a technique for inverting geodetic, extrusive flux, and other types of data using a physics‐based model of an effusive silicic volcanic eruption to estimate the geometry, pressure, depth, and volatile content of a magma chamber, and properties of the conduit linking the chamber to the surface. A Bayesian inverse formulation makes it possible to easily incorporate independent information into the inversion, such as petrologic estimates of melt water content, and yields probabilistic estimates for model parameters and other properties of the volcano. Probability distributions are sampled using a Markov‐Chain Monte Carlo algorithm. We apply the technique using GPS and extrusion data from the 2004–2008 eruption of Mount St. Helens. In contrast to more traditional inversions such as those involving geodetic data alone in combination with kinematic forward models, this technique is able to provide constraint on properties of the magma, including its volatile content, and on the absolute volume and pressure of the magma chamber. Results suggest a large chamber of >40 km3 with a centroid depth of 11–18 km and a dissolved water content at the top of the chamber of 2.6–4.9 wt%.