Magma storage and migration associated with the 2011-2012 El Hierro eruption: Implications for crustal magmatic systems at oceanic island volcanoes
Magma storage and migration associated with the 2011-2012 El Hierro eruption: Implications for crustal magmatic systems at oceanic island volcanoes
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DOI：
10.1002/jgrb.50289
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发表时间：
2013-08-01
影响因子：
3.9
通讯作者：
Sansosti, Eugenio
中科院分区：
文献类型：
--
作者：
Gonzalez, Pablo J.;Samsonov, Sergey V.;Sansosti, Eugenio
从2011年7月开始，在年轻的海洋岛屿火山耶罗岛观测到异常地震活动。在2011年10月12日，这一过程导致了一次海底NW-SE裂缝喷发的开始，距离最初的地震地点大约15公里，这表明岩浆有明显的侧向迁移。在这里，我们进行多频，多传感器干涉分析的星载雷达图像采集使用三个不同的卫星系统（雷达卫星-2，ENVISAT，和COSMO-SkyMed（小卫星星座地中海盆地观测））。这些数据充分反映了喷发前和喷发时的情况。地面变形的弹性模拟被用来约束与岩浆活动相关的动力学。这项研究代表了加那利群岛火山的第一个大地测量约束的活动岩浆管道系统模型，也是迄今为止海底火山活动的少数例子之一。大地测量结果揭示了两个空间上不同的浅（地壳）岩浆库，一个更深的中央源（9.54.0km），和一个较浅的岩浆库在南部裂谷的侧翼（4.52.0km）。更深的源被重新充注，解释了相对较长的玄武岩喷发，有助于观察到的全岛隆起过程，并验证了建议的活动岩浆底侵作用。最浅的源可能是一个初期的水库，有利于分离结晶在其他加那利群岛观察。从这次喷发的数据支持浅地壳岩浆系统的深度和长期的岩浆供应率和海洋岩石圈年龄之间的关系。这种关系意味着控制海洋岛屿火山中浅层（地壳）岩浆系统的存在/深度的因素是岩石圈热机械行为。
Starting in July 2011, anomalous seismicity was observed at El Hierro Island, a young oceanic island volcano. On 12 October 2011, the process led to the beginning of a submarine NW-SE fissural eruption at similar to 15km from the initial earthquake loci, indicative of significant lateral magma migration. Here we conduct a multifrequency, multisensor interferometric analysis of spaceborne radar images acquired using three different satellite systems (RADARSAT-2, ENVISAT, and COSMO-SkyMed (Constellation of Small Satellites for Mediterranean Basin Observation)). The data fully captures both the pre-eruptive and coeruptive phases. Elastic modeling of the ground deformation is employed to constrain the dynamics associated with the magmatic activity. This study represents the first geodetically constrained active magmatic plumbing system model for any of the Canary Islands volcanoes, and one of the few examples of submarine volcanic activity to date. Geodetic results reveal two spatially distinct shallow (crustal) magma reservoirs, a deeper central source (9.54.0km), and a shallower magma reservoir at the flank of the southern rift (4.52.0km). The deeper source was recharged, explaining the relatively long basaltic eruption, contributing to the observed island-wide uplift processes, and validating proposed active magma underplating. The shallowest source may be an incipient reservoir that facilitates fractional crystallization as observed at other Canary Islands. Data from this eruption supports a relationship between the depth of the shallow crustal magmatic systems and the long-term magma supply rate and oceanic lithospheric age. Such a relationship implies that a factor controlling the existence/depth of shallow (crustal) magmatic systems in oceanic island volcanoes is the lithosphere thermomechanical behavior.