Frequency and magnitude of volcanic eruptions controlled by magma injection and buoyancy
Frequency and magnitude of volcanic eruptions controlled by magma injection and buoyancy
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DOI：
10.1038/ngeo2041
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发表时间：
2014-02-01
影响因子：
18.3
通讯作者：
Pinel, Virginie
中科院分区：
文献类型：
--
作者：
Caricchi, Luca;Annen, Catherine;Pinel, Virginie
超级火山爆发是极其罕见的事件。事实上，全球火山爆发的频率与单一事件中释放的岩浆量成反比（1，2）。已知岩浆供应速率、地壳和岩浆的力学性质以及构造体制在控制喷发频率和强度（3-7）方面发挥着作用，但它们的相对贡献尚未量化。在这里，我们使用一个热力学数值模型的岩浆注入到地壳和蒙特卡洛模拟，探讨控制复发率的不同规模的喷发的因素。我们发现，岩浆供应到上地壳的速度控制了单次喷发的体积。岩浆注入次火山储层的时间间隔，在恒定的岩浆供应率，决定了喷发前岩浆活动的持续时间。我们的模拟再现了观测到的喷发量和岩浆房停留时间之间的关系，并复制了观测到的喷发量和破火山口尺寸之间的相关性（8，9）。我们还发现，岩浆浮力是触发超级喷发的关键，而与岩浆注入相关的加压是负责相对较小和频繁的喷发。我们的发现有助于提高我们破译火山系统长期活动模式的能力。
Super-eruptions are extremely rare events. Indeed, the global frequency of explosive volcanic eruptions is inversely proportional to the volume of magma released in a single event(1,2). The rate of magma supply, mechanical properties of the crust and magma, and tectonic regime are known to play a role in controlling eruption frequency and magnitude(3-7), but their relative contributions have not been quantified. Here we use a thermomechanical numerical model of magma injection into Earth's crust and Monte Carlo simulations to explore the factors controlling the recurrence rates of eruptions of different magnitudes. We find that the rate of magma supply to the upper crust controls the volume of a single eruption. The time interval between magma injections into the subvolcanic reservoir, at a constant magma-supply rate, determines the duration of the magmatic activity that precedes eruptions. Our simulations reproduce the observed relationship between eruption volume and magma chamber residence times and replicate the observed correlation between erupted volumes and caldera dimensions(8,9). We also find that magma buoyancy is key to triggering super-eruptions, whereas pressurization associated with magma injection is responsible for relatively small and frequent eruptions. Our findings help improve our ability to decipher the long-term activity patterns of volcanic systems.