Magmatic intrusions play a vital role in accommodating extensional stresses in continental rifts but also in feeding volcanic systems. The location, orientation and timescale of dyke intrusions are dictated by the interaction of regional and local stresses, the effect of pre‐existing weaknesses and the composition of magma. Observing active intrusions can provide important information regarding the interaction between magmatic processes and the tectonic stress field during continental rifting. We focus on a seismic swarm that occurred in 2015 to the northeast of Fentale volcano, in the Main Ethiopian Rift (MER) and use radar interferometry to study surface deformation associated with the seismic swarm. Interferograms show a pattern of dyke induced deformation, with a model estimate of volume change of 33×10⁶±0.6×10⁶m³at a depth range of 5.4 to 8 km. We use a small baseline subset algorithm to calculate line‐of‐sight time‐series and find that the displacements decay exponentially with a decay constant of ~83 days. Coupled source‐sink models suggest that such slow dyke intrusions require a high viscosity rhyolitic magma. The difference in behaviour between Fentale and other caldera systems in the MER, which show multi‐year cycles of inflation and deflation, suggests fundamental differences in magma composition and architecture of the plumbing system. This is the first direct observation of a dyke intrusion in the MER and provides new constraints on the temporal‐spatial patterns of stress and strain that occur during continental rifting. Whether this activity is transient or a long‐term feature associated with rift evolution is an open question.

中文翻译：

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来自2015年Fentale地震群的主要埃塞俄比亚大裂谷活跃流纹岩堤入侵的证据

岩浆侵入在适应大陆裂谷中的伸展应力中也起着至关重要的作用，但在火山系统中也起着重要作用。堤防侵入的位置，方向和时间尺度取决于区域和局部应力的相互作用，既有弱点的影响以及岩浆的组成。观察主动侵入可以提供有关大陆裂谷过程中岩浆作用与构造应力场之间相互作用的重要信息。我们关注于2015年发生在芬塔莱火山东北部，主埃塞俄比亚裂谷（MER）的地震群，并使用雷达干涉测量法研究了与地震群相关的表面变形。干涉图显示堤坝诱发变形的模式，模型估计的体积变化为33×10 ⁶±0.6×10 ⁶ m ³在5.4至8 km的深度范围内。我们使用一个小的基线子集算法来计算视线时间序列，发现位移以〜83天的衰减常数呈指数衰减。耦合的源汇模型表明，这种缓慢的堤防侵入需要高粘度的流纹岩浆。MER中的Fentale和其他破火山口系统在行为上的差异显示了多年的通货膨胀和通货紧缩周期，这表明了岩浆成分和管道系统结构的根本差异。这是对MER堤防入侵的首次直接观察，并为大陆裂谷期间出现的应力和应变的时空格局提供了新的约束。这种活动是短暂的还是与裂谷演化有关的长期特征是一个悬而未决的问题。