The influence of cooling, crystallisation and re-melting on the interpretation of geodetic signals in volcanic systems
The influence of cooling, crystallisation and re-melting on the interpretation of geodetic signals in volcanic systems
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DOI：
10.1016/j.epsl.2013.12.002
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发表时间：
2014-02-15
影响因子：
5.3
通讯作者：
Ebmeier, Susanna
中科院分区：
文献类型：
--
作者：
Caricchi, Luca;Biggs, Juliet;Ebmeier, Susanna
火山建筑物的变形通常归因于火山管道系统内岩浆的运动，但各种岩浆过程能够产生显着的体积变化，也可能产生变形。为了了解喷发前岩浆系统的演化并正确解释监测信号，有必要量化热液系统结晶、脱气和膨胀等过程可能产生的地表变形的模式和时间尺度。我们展示了如何将岩石学和热建模相结合应用于大地测量观测，以识别火山动荡期间岩浆储层中发生的过程。热建模和岩石学用于确定与冷却、结晶和气体逸出相关的时间尺度和体积变化。这些计算可以快速执行，并突出显示最有可能导致一组监测参数变化的过程。然后，我们考虑活跃岩浆系统附近发生的其他过程产生的变形的大小和时间尺度。我们将这些模型应用于阿留申群岛奥克莫克火山 1997 年至 2008 年喷发期间的时间序列大地测量数据，检查涉及结晶浅岩浆体的结晶、脱气和重熔的场景，包括粘弹性壳或热液系统。大地测量结果与注入水饱和玄武岩、随后发生轻微结晶和脱气的情况一致。其他场景与变形信号的幅度或速率不兼容。 (C) 2013 Elsevier B.V. 保留所有权利。
Deformation of volcanic edifices is typically attributed to the movement of magma within the volcanic plumbing system, but a wide range of magmatic processes are capable of producing significant volume variations and may also produce deformation. In order to understand the evolution of magmatic systems prior to eruption and correctly interpret monitoring signals, it is necessary to quantify the patterns and timescales of surface deformation that processes such as crystallisation, degassing and expansion of the hydrothermal system can produce. We show how the combination of petrology and thermal modelling can be applied to geodetic observations to identify the processes occurring in a magmatic reservoir during volcanic unrest. Thermal modelling and petrology were used to determine the timescales and volumetric variations associated with cooling, crystallisation and gas exsolution. These calculations can be performed rapidly and highlight the most likely processes responsible for the variation of a set of monitoring parameters. We then consider the magnitude and timescales of deformation produced by other processes occurring within the vicinity of an active magma system. We apply these models to a time series of geodetic data spanning the period between the 1997 and 2008 eruptions of Okmok volcano, Aleutians, examining scenarios involving crystallisation, degassing and remelting of the crystallising shallow magmatic body and including a viscoelastic shell or hydrothermal system. The geodetic observations are consistent with the injection of a water-saturated basalt, followed by minor crystallisation and degassing. Other scenarios are not compatible either with the magnitude or rate of the deformation signals. (C) 2013 Elsevier B.V. All rights reserved.