Regional controls on volcano seismicity along the Aleutian arc
Regional controls on volcano seismicity along the Aleutian arc
复制标题
对阿留申岛弧沿线火山地震活动的区域控制
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
C. Cameron
中科院分区：
文献类型：
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作者：
H. Buurman;C. Nye;M. West;C. Cameron
我们利用近10年来在46座火山记录的地震数据，确定了沿阿留申弧的火山地震活动模式。弧中心部分的火山——从Aniakchak到okmok——与深度低于15公里的地震活动密切相关。我们还通过汇编已发表的地球化学数据，对地震监测的火山SiO2组成的中位数重量百分比进行了研究。研究发现，东部的长英质火山作用向西部的基性火山作用过渡发生在火山地震深度分布发生变化的同一地区。由于深部火山地震通常被认为是由岩浆上升穿过深部地壳（即深度bbb15 km）产生的，我们的研究结果表明，与西部和东部地区相比，岩浆上升在弧的中部地区更为丰富。这一观测结果与阿留申岛弧上最大和历史上最活跃的火山的位置一致，这些火山位于产生丰富的深部火山地震活动的同一地区。我们提出了两个模型来解释这些明显的岩浆通量变化：(1)一个基于应力的模型，其中俯冲倾角和雅库塔地块的碰撞影响了上部板块的应力状态，抑制了弧东西部地区岩浆的上升；(2)一个基于熔体的模型，其中通过含水沉积物和俯冲断裂带，下沉的板块增加了水，在弧中部地区产生了更多的岩浆。
We identify patterns in volcano seismicity along the Aleutian arc using nearly 10 years of seismic data recorded at 46 volcanoes. The volcanoes in the central portion of the arc—those located from Aniakchak to Okmok—are associated with significantly more seismicity at depths below 15 km. We also examine the median weight percent SiO2 compositions of the seismically monitored volcanoes by compiling published geochemical data. We find that the transition between felsic volcanism in the east to more mafic volcanism in the west occurs in the same region where the depth distribution of volcanic earthquakes changes. Since deep volcanic earthquakes are often thought to be generated by the ascent of magma through the deep crust (i.e., depths > 15 km), our results suggest that magma ascent is more prolific in the central part of the arc compared to the western and eastern regions. This observation is in agreement with the location of the largest and most historically active volcanoes in the Aleutian arc, which are found in same region that generates abundant deep volcano seismicity. We propose two models to explain these apparent variations in magmatic flux: (1) a stress‐based model, in which subduction obliquity and the collision of the Yakutat block affect the stress regime in the upper plate, inhibiting the rise of magma in eastern and western regions of the arc and (2) a melt‐based model, where more magma is generated in the central region of the arc through increased H2O in the downgoing slab via water‐laden sediments and subducting fracture zones.