The lateral extent of volcanic interactions during unrest and eruption
The lateral extent of volcanic interactions during unrest and eruption
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DOI：
10.1038/ngeo2658
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发表时间：
2016-04-01
影响因子：
18.3
通讯作者：
Cashman, Katharine
中科院分区：
文献类型：
--
作者：
Biggs, Juliet;Robertson, Elspeth;Cashman, Katharine
火山喷发经常同时发生（1-4）或从多个岩浆库中流出（5，6）。岩浆系统之间的这种横向相互作用归因于应力变化（7，8）或水力联系（4，8 -10），但耦合喷发发生的精确条件尚未量化。在这里，我们使用干涉合成孔径雷达卫星数据来分析在肯尼亚裂谷火山动荡所产生的表面变形。我们确定了几个岩浆源位于2-5公里的深度，重要的是，源的间隔小于约10公里的相互作用，而那些间隔超过约25公里的间隔不。然而，在地质历史中，相距25公里的火山相互作用（1，11）。因此，火山耦合不是简单地由岩浆库之间的距离控制。然后，我们考虑全球不同的构造环境，包括板内火山，如夏威夷和黄石，弧火山在阿拉斯加和智利，和其他裂谷环境，如新西兰，冰岛和阿法尔。我们发现，最紧密间隔的岩浆相互作用控制的范围内的一个浅的晶体泥层，应力变化可以耦合大喷发的距离约为20-40公里，只有大型岩脉侵入或俯冲地震可以产生耦合喷发的距离约为50-100公里。
Volcanic eruptions often occur simultaneously(1-4) or tap multiple magma reservoirs(5,6). Such lateral interactions between magmatic systems are attributed to stress changes(7,8) or hydraulic connections(4,8-10) but the precise conditions under which coupled eruptions occur have yet to be quantified. Here we use interferometric synthetic aperture radar satellite data to analyse the surface deformation generated by volcanic unrest in the Kenyan Rift. We identify several magma sources located at depths of 2-5 km; importantly, sources that are spaced less than about 10 km apart interact, whereas those spaced more than about 25 km apart do not. However, volcanoes up to 25 km apart have interacted in the geologic past(1,11). Thus, volcanic coupling is not simply controlled by the distance between the magma reservoirs. We then consider different tectonic settings globally, including intraplate volcanoes such as Hawaii and Yellowstone, arc volcanism in Alaska and Chile, and other rift settings, such as New Zealand, Iceland and Afar. We find that the most closely spaced magmatic interactions are controlled by the extent of a shallow crystal mush layer, stress changes can couple large eruptions over distances of about 20-40 km, and only large dyke intrusions or subduction earthquakes could generate coupled eruptions over distances of about 50-100 km.