Crustal structure and magmato-tectonic processes in an active rift (Asal-Ghoubbet, Afar, East Africa): 1. Insights from a 5-month seismological experiment
Crustal structure and magmato-tectonic processes in an active rift (Asal-Ghoubbet, Afar, East Africa): 1. Insights from a 5-month seismological experiment
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DOI：
10.1029/2005jb003940
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发表时间：
2007-05
影响因子：
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通讯作者：
C. Doubre;I. Manighetti;C. Dorbath;L. Dorbath;E. Jacques;J. Delmond
中科院分区：
文献类型：
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作者：
C. Doubre;I. Manighetti;C. Dorbath;L. Dorbath;E. Jacques;J. Delmond
我们试图描述大陆裂谷过程中岩浆活动和构造活动是如何联合收割机和相互作用的。我们在两个配套文件中解决这个问题。在这两个，我们分析了地震活动发生在一个活跃的岩浆构造裂谷，Asal-Ghoubbet（东非），以确定其活动负责的功能和/或过程。在这里，我们报告了我们在裂缝中进行的为期5个月的实验结果。部署了11个地震仪，以补充8个台站的永久网络。这使得在裂谷中记录了10400次地震; 200次事件可以很好地定位（精度5-6公里）岩浆库。大多数事件集中在管道的顶部（3-4公里处），并由火山（环）和构造断层上的上下滑动破裂引起，这些断层在深度上包围管道。上下运动可能是由岩浆库中的压力变化驱动的。因此，虽然有少数裂谷断层与地震活动有关，但大多数在实验期间保持地震沉默。在配套的论文中，我们分析了裂谷在最后一次裂谷活动之后的23年中的地震活动。这证实了菲耶尔-鲨鱼湾管道系统在整个裂谷活动中的重要性。
We seek to characterize how magmatic and tectonic activities combine and interact during the continental rifting process. We address this question in two companion papers. In both, we analyze the seismicity that occurs in an active magmato-tectonic rift, Asal-Ghoubbet (East Africa), to identify the features and/or processes responsible for its activity. Here, we report results from a 5-month experiment that we conducted in the rift. Eleven seismometers were deployed to complement the eight-station permanent network. This allowed recording ∼400 earthquakes in the rift; 200 events could be well located (precision 5–6 km) magma reservoir. Most events concentrate at the roof of the pipe (at 3–4 km) and result from up and down slip ruptures on both the volcanic (ring) and tectonic faults that enclose the pipe at depth. The up and down motions are likely driven by pressure changes in the magma reservoir. Hence, although a few rift faults were associated with seismicity, most remained seismically silent during the experiment. In the companion paper, we analyze the seismic activity in the rift over the 23 years that followed its last rifting episode. This confirms the importance of the Fieale-Shark Bay plumbing system in the overall rift behavior.