In extending volcanic arcs such as the Aegean, tectonic processes exert a significant control on magmatism. Spanning scales from 1 to 10s of km, volcanic vents, edifices, and eruptive centers follow the orientation of, and are located near, fault zones. Whether this tectonic control on magmatism results from individual faults/fractures weakening the crust or because regional stresses control magma input into the crust is debated. Here we investigate the scales of tectonic and magmatic interactions, specifically focusing on the role of local-scale (<10 km) faults/fractures in controlling magmatism. We infer local-scale fault/fracture orientations from anisotropic active-source P-wave travel-time tomography to investigate tectonic and magmatic interactions in the upper crust of Santorini Volcano, Greece, and the actively deforming region to the east. We use the anisotropy magnitude and seismic velocity reduction to model the relative distribution of both consistently oriented and randomly oriented faults/fractures. Our results show that oriented faulting/fracturing resulting from regional-scale (>10 km) tectonic stresses is distributed broadly across the region at 2–3 km depth, approximately paralleling volcanic/magmatic features. On a local-scale, magmatism is neither localized in areas of higher oriented fault/fracture density, nor is it accommodating enough extensional strain to inhibit oriented faulting/fracturing of host rock. The alignment of magmatic features shows strong tectonic control despite the lack of correlation with local oriented fault/fracture density. These results suggest that magmatic processes are strongly influenced by regional-scale, not local-scale, tectonic processes. We infer regional processes have a greater impact on magmatism than local features due to their greater effect at depth.

中文翻译：

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圣托里尼岛周围活动断层/压裂与岩浆活动的关系：来自活动源断层扫描实验的地震各向异性

在像爱琴海这样延伸的火山弧中，构造过程对岩浆活动产生了显着的控制。跨度从 1 到 10 公里的火山喷口、建筑物和喷发中心沿着断层带的方向并位于断层带附近。这种对岩浆活动的构造控制是由于单个断层/裂缝削弱地壳还是因为区域应力控制了岩浆输入地壳，这一点存在争议。在这里，我们研究了构造和岩浆相互作用的尺度，特别关注局部尺度（<10 公里）断层/裂缝在控制岩浆活动中的作用。我们从各向异性活动源 P 波走时断层扫描推断局部尺度断层/裂缝方向，以研究希腊圣托里尼火山上地壳的构造和岩浆相互作用，以及东部的活跃变形区域。我们使用各向异性震级和地震速度衰减来模拟一致定向和随机定向的断层/裂缝的相对分布。我们的结果表明，由区域尺度（> 10 公里）构造应力引起的定向断层/压裂广泛分布在该地区 2-3 公里深度，大致平行于火山/岩浆特征。在局部尺度上，岩浆作用既不局限在定向断层/裂缝密度较高的区域，也不能容纳足够的拉伸应变来抑制主岩的定向断层/破裂。尽管与局部定向断层/裂缝密度缺乏相关性，但岩浆特征的排列显示出强烈的构造控制。这些结果表明，岩浆过程受到区域尺度而非局部尺度构造过程的强烈影响。我们推断区域过程对岩浆活动的影响比局部特征更大，因为它们在深度上的影响更大。