Pre‐eruptive electrical signals at active volcanoes are generally interpreted in terms of electrokinetic processes. Spatio‐temporal self‐potential (SP) signals can be caused by strain‐induced fluid flow in volcanic aquifers, however, previous studies lack the quantitative assessments of these phenomena and the underpinning poroelastic responses. Here we use Finite‐Element Analysis to study poroelastic responses induced by subsurface stressing from sill and dike sources by jointly solving for ground displacements, pore pressure, and SP signals. We evaluate the influence of pressure source orientation on the poroelastic response in two different volcanic aquifers (pyroclastic and lava flow) to provide insights on emergent geodetic and SP signals and their sensitivity to governing parameters. Strain‐induced SP amplitudes deduced from a reference parameter set vary in both aquifer models and are of negative polarity (−0.35 and −22.6 mV) for a pressurized dike and of positive polarity (+4 and +20 mV) for a pressurized sill. Importantly, we find uniquely different SP and ground displacement patterns from either sill or dike intrusions. Our study shows that SP signals are highly sensitive to the subsurface Young's modulus, streaming potential coupling coefficient and electrical conductivity of the poroelastic domains. For the set of parameters tested, the dike model predicts SP amplitudes of up to −947 mV which are broadly representative of recorded amplitudes from active volcanoes. Our study demonstrates that electrokinetic processes reflect magma‐induced stress and strain variations and highlights the potential of joint geodetic and SP studies to gain new insights on causes of volcanic unrest.

中文翻译：

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磁应力对自势信号的动电贡献

活跃火山喷发前的电信号通常用电动过程来解释。时空自电位（SP）信号可能是由应变引起的火山岩含水层中的流体流动引起的，但是，先前的研究缺乏对这些现象和基础孔隙弹性反应的定量评估。在这里，我们通过有限元分析，通过共同求解地面位移，孔隙压力和SP信号，研究窗台和堤防源的地下应力引起的孔隙弹性响应。我们评估了两种不同的火山含水层（火山碎屑和熔岩流）中压力源方向对孔隙弹性响应的影响，从而提供了对新兴大地测量和SP信号及其对控制参数的敏感性的见识。从参考参数集推导出的应变诱发的SP振幅在两个含水层模型中都不同，对于加压堤坝，其为负极性（-0.35和-22.6 mV），对于加压坝基，其为正极性（+4和+20 mV）。重要的是，我们发现门槛或堤防的侵入都有独特的SP和地面位移模式。我们的研究表明，SP信号对地下杨氏模量，流电耦合系数和多孔弹性域的电导率高度敏感。对于测试的参数集，堤坝模型预测的SP振幅最高为-947 mV，这大致代表了活火山记录的振幅。