当前位置: X-MOL 学术J. Geophys. Res. Solid Earth › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Alteration-Induced Volcano Instability at La Soufrière de Guadeloupe (Eastern Caribbean)
Journal of Geophysical Research: Solid Earth ( IF 3.9 ) Pub Date : 2021-07-31 , DOI: 10.1029/2021jb022514
Michael J. Heap 1, 2 , Tobias S. Baumann 3, 4 , Marina Rosas‐Carbajal 5 , Jean‐Christophe Komorowski 5 , H. Albert Gilg 6 , Marlène Villeneuve 7 , Roberto Moretti 5, 8 , Patrick Baud 1 , Lucille Carbillet 1 , Claire Harnett 9 , Thierry Reuschlé 1
Affiliation  

Volcanoes are unstable structures that deform laterally and frequently experience mass wasting events. Hydrothermal alteration is often invoked as a mechanism that contributes significantly to volcano instability. We present a study that combines laboratory experiments, geophysical data, and large-scale numerical modeling to better understand the influence of alteration on volcano stability, using La Soufrière de Guadeloupe (Eastern Caribbean) as a case study. Laboratory experiments on variably altered (advanced argillic alteration) blocks show that uniaxial compressive strength, Young's modulus, and cohesion decrease as a function of increasing alteration, but that the internal friction angle does not change systematically. Simplified volcano cross sections were prepared (a homogenous volcano, a volcano containing the alteration zone identified by a recent electrical survey, and a volcano with an artificially enlarged area of alteration) and mechanical properties were assigned to zones corresponding to unaltered and altered rock. Numerical modeling performed on these cross sections, using a hydro-thermo-mechanical modeling code, show (a) the importance of using upscaled values in large-scale models and (b) that alteration significantly increases volcano deformation and collapse volume. Finally, we combined published muon tomography data with our laboratory data to create a 3D strength map, exposing a low-strength zone beneath the southern flank of the volcano coincident with the hydrothermal system. We conclude that hydrothermal alteration decreases volcano stability and thus expedites volcano spreading and increases the likelihood of mass wasting events and associated volcanic hazards. Hydrothermal alteration, and its evolution, should therefore be monitored at active volcanoes worldwide.

中文翻译:

La Soufrière de Guadeloupe(东加勒比海)的改造引起的火山不稳定性

火山是不稳定的结构,会横向变形并经常经历质量浪费事件。热液蚀变通常被认为是导致火山不稳定的一种机制。我们以 La Soufrière de Guadeloupe(东加勒比海)为例,介绍了一项结合实验室实验、地球物理数据和大规模数值建模的研究,以更好地了解变化对火山稳定性的影响。对可变变质(高级泥质变质)块体的实验室实验表明,单轴抗压强度、杨氏模量和内聚力随变质增加而降低,但内摩擦角不会系统地改变。准备了简化的火山横截面(同质火山,一座包含最近一次电气调查确定的蚀变带的火山,以及一座人为扩大蚀变区域的火山)和机械特性被分配给与未蚀变和蚀变岩石相对应的区域。使用水热力学建模代码对这些横截面进行的数值建模表明 (a) 在大型模型中使用放大值的重要性和 (b) 改变显着增加了火山变形和坍塌体积。最后,我们将已发表的μ子断层扫描数据与我们的实验室数据相结合,创建了一张 3D 强度图,揭示了火山南翼下方与热液系统重合的低强度区域。我们得出的结论是,热液蚀变降低了火山的稳定性,从而加速了火山的蔓延,并增加了大规模浪费事件和相关火山灾害的可能性。因此,应该在全世界的活火山上监测热液蚀变及其演化。
更新日期:2021-08-16
down
wechat
bug