Magma plumbing system and seismicity of an active mid-ocean ridge volcano.
Magma plumbing system and seismicity of an active mid-ocean ridge volcano.
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DOI：
10.1038/srep42949
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发表时间：
2017-02-20
影响因子：
4.6
通讯作者：
Scholz JR
中科院分区：
文献类型：
--
作者：
Schmid F;Schlindwein V;Koulakov I;Plötz A;Scholz JR
在大洋中脊，火山活动一般随扩张速度而减少，但令人惊讶的是，大规模的火山中心出现在扩张最慢的海脊。这些火山可能会发生意想不到的强烈地震和剧烈的海底爆发。由于缺乏地球物理数据和难以捕捉其罕见的岩浆活动阶段，我们对形成这些火山中心的地球动力学过程的了解仍然不完整。我们提出了一个当地的地震断层图像的岩浆管道系统下的第8段火山在超低速扩张西南印度洋脊。断层扫描显示火山下有一个局部熔化的封闭区域。我们推断，从那里融化水平运输到邻近的山脊段在35公里的距离，微震群和侵入震颤发生，表明正在进行的岩浆活动。在我们的研究之前，第8段火山周围的Teleseeps地震表明，目前的岩浆扩张事件可能已经持续了十多年，因此其时间范围大大超过了快速开放的洋中脊频繁的短暂扩张事件。
At mid-ocean ridges volcanism generally decreases with spreading rate but surprisingly massive volcanic centres occur at the slowest spreading ridges. These volcanoes can host unexpectedly strong earthquakes and vigorous, explosive submarine eruptions. Our understanding of the geodynamic processes forming these volcanic centres is still incomplete due to a lack of geophysical data and the difficulty to capture their rare phases of magmatic activity. We present a local earthquake tomographic image of the magma plumbing system beneath the Segment 8 volcano at the ultraslow-spreading Southwest Indian Ridge. The tomography shows a confined domain of partial melt under the volcano. We infer that from there melt is horizontally transported to a neighbouring ridge segment at 35 km distance where microearthquake swarms and intrusion tremor occur that suggest ongoing magmatic activity. Teleseismic earthquakes around the Segment 8 volcano, prior to our study, indicate that the current magmatic spreading episode may already have lasted over a decade and hence its temporal extent greatly exceeds the frequent short-lived spreading episodes at faster opening mid-ocean ridges.