Structure of a recharging crustal magma plumbing system at the Santorini arc volcano

圣托里尼岛弧火山地壳岩浆补给管道系统的结构

• 批准号: 2023338
• 负责人: Emilie Hooft Toomey
• 金额: $ 29.3万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2023338&HistoricalAwards=false
• 关键词: Structure; recharging; crustal; magma; plumbing

This project will improve the understanding of magma storage under volcanoes - a critical input for volcanic hazard assessments. Magma beneath a volcano can be detected using geophysical tools, but the shape of the magma plumbing systems that underlie volcanoes is still not known. For hazard analyses it is critical to know what fraction of a magma is molten rock (melt) and what fraction are crystals; this ratio controls how fluid the magma is and thus how easy it is for an eruption to occur. After a large, explosive eruption of the volcano, the subsurface magma system has to reassemble. To resolve the detailed structure of a recharging crustal magma plumbing system beneath an arc volcano, this project will use a unique seismic dataset, PROTEUS, from Santorini volcano in Greece. The PROTEUS dataset probed the volcano in unprecedented detail. The data reveal a column of broken rock that is narrowly confined beneath the northern caldera basin. Below this structure lies the uppermost part of the magma system. This project will further analyze the PROTEUS seismic data as well as model the stresses with the volcano to: (i) image the magma plumbing system of the volcano to great depths (the base of the crust); (ii) determine the melt content of magmas located in the mid- and upper-crust; (iii) explore how volcano internal structure and by regional setting control magma distribution within the volcano. When recruiting graduate and undergraduate students, diversity in STEM training will be prioritized. This project will build on existing international collaborations including with four different European scientific institutions and with an International Ocean Drilling expedition to Santorini. To most effectively bring the science results to the public and local decision makers, the project engages Greek collaborators and a science communications expert. This study will provide a framework for volcanic and seismic hazards assessment at Santorini, where the dramatic landscape draws over 2 million tourists per year.Current models of volcano plumbing systems predict vertically extensive magma systems dominated by low melt-fraction crystal mushes where differentiation occurs in the lower and mid crust and magma accumulation in the upper crust. However, the detailed geometry, distribution, and composition of melt throughout the crust remain poorly known. These conceptual models also predict that the existence of eruptible melt-rich magma chambers prior to Plinian events is short-lived. Of interest is how the magma system is reshaped after a caldera-forming eruption. This project will address two outstanding science questions: (1) What is the high-resolution structure of the magmatic system at an arc volcano and what are the melt contents throughout the crust? And (2) How is magma movement affected by caldera collapse structures and regional stresses? To resolve the detailed structure of a recharging crustal magma plumbing system at an arc volcano, this project leverages the unique PROTEUS active-source seismic dataset from the well-studied Santorini volcano. These data probed the volcano with unprecedented wavefield density and, to date, tomographic analysis of first arriving P-waves has resolved the structure of the uppermost crust at, and around, the volcanic edifice. The results reveal a low-velocity, porous column that is narrowly confined beneath the northern caldera basin beneath which is an upper-crustal magma system. Here the PROTEUS seismic dataset will be exploited further to model the stress state. The proposed analyses will: (i) determine the structure of the magmatic system below the currently-resolved upper-crustal reservoir through tomographic inversion of deeper turning rays and Moho reflections; (ii) better constrain the melt content of the mid- and upper- crust through joint Vp/Vs tomography and modeling of secondary arrivals; (iii) interpret the seismic results in terms of physical properties; and (iv) explore how the internal structure of the edifice and regional stresses affect magma accumulation within the volcano through modeling and seismicity analysis. This project will also build international collaborations including four different European institutions and synergies with an IODP proposal. Diversity in STEM training will be prioritized when recruiting graduate and undergraduate students. This study will provide a framework for volcanic and seismic hazards assessment at Santorini, where the dramatic landscape draws over 2 million tourists per year. To most effectively bring the results to the public and local decision makers, the project leverages Greek collaborators and a science communications expert.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

这个项目将提高对火山下岩浆储存的认识，这是火山危险评估的一个重要输入。火山下的岩浆可以用地球物理工具探测到，但是火山下的岩浆管道系统的形状仍然未知。对于危险分析来说，知道岩浆的哪一部分是熔融岩石（熔体），哪一部分是晶体是至关重要的；这个比例控制着岩浆的流动性，从而决定了火山爆发的容易程度。在一次大规模的火山爆发之后，地下岩浆系统必须重新组合。为了解决弧状火山下地壳岩浆补给管道系统的详细结构，该项目将使用来自希腊圣托里尼火山的独特地震数据集PROTEUS。PROTEUS数据集以前所未有的细节探测了这座火山。数据显示，在北部的火山口盆地下方有一柱破碎的岩石。在这个构造的下面是岩浆系统的最上层。该项目将进一步分析PROTEUS地震数据，并对火山的应力进行建模，以便：(i)对火山的岩浆管道系统进行深度成像（地壳底部）；（ii）确定中上部地壳岩浆的熔体含量；（三）探索火山内部构造和区域环境如何控制火山内部岩浆分布。在招收研究生和本科生时，将优先考虑STEM培训的多样性。该项目将以现有的国际合作为基础，包括与四个不同的欧洲科学机构和圣托里尼国际海洋钻探考察队的合作。为了最有效地将科学成果带给公众和当地决策者，该项目聘请了希腊合作者和一名科学传播专家。这项研究将为圣托里尼岛的火山和地震灾害评估提供一个框架，圣托里尼岛的壮观景观每年吸引200多万游客。目前的火山管道系统模型预测，垂直扩展的岩浆系统以低熔体分数的晶体糊状物为主，其中在下地壳和中地壳发生分异，岩浆在上地壳聚集。然而，详细的几何形状、分布和整个地壳的熔融成分仍然知之甚少。这些概念模型还预测，在普林尼期事件之前存在的可喷发的富含熔体的岩浆房是短暂的。令人感兴趣的是岩浆系统在形成火山口的喷发后是如何重塑的。该项目将解决两个突出的科学问题：(1)弧火山岩浆系统的高分辨率结构是什么？整个地壳的熔融物含量是什么？(2)岩浆运动如何受到破火山口崩塌构造和区域应力的影响？为了解决弧型火山地壳岩浆补给管道系统的详细结构，该项目利用了来自圣托里尼火山的独特的PROTEUS活动震源数据集。这些数据以前所未有的波场密度探测了火山，迄今为止，对首次到达的p波的层析分析已经解决了火山大厦及其周围最上层地壳的结构。结果显示，在北部火山口盆地下方狭窄地局限着一个低速多孔柱，火山口盆地下方是一个地壳上层岩浆系统。在这里，将进一步利用PROTEUS地震数据集来模拟应力状态。建议的分析将：(1)通过深部转弯射线和莫霍反射层析反演，确定目前已分辨的上地壳储层下方岩浆系统的结构；（ii）通过联合Vp/Vs层析成像和二次到达模拟，更好地约束了中上部地壳的熔体含量；（iii）根据物理性质解释地震结果；(4)通过模拟和地震活动性分析，探讨火山内部构造和区域应力对火山岩浆聚集的影响。该项目还将建立国际合作，包括四个不同的欧洲机构，并与IODP提案产生协同效应。在招收研究生和本科生时，将优先考虑STEM培训的多样性。这项研究将为圣托里尼岛的火山和地震灾害评估提供一个框架，圣托里尼岛的壮观景观每年吸引200多万游客。为了最有效地将结果带给公众和当地决策者，该项目利用了希腊合作者和一名科学传播专家。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Submarine terraced deposits linked to periodic collapse of caldera-forming eruption columns

海底梯田沉积物与形成火山口的喷发柱的周期性崩塌有关

• DOI: 10.1038/s41561-023-01160-z
• 发表时间: 2023
• 期刊: Nature Geoscience
• 影响因子: 18.3
• 作者: Gilchrist, Johan T.;Jellinek, A. Mark;Hooft, Emilie E.;Wanket, Sean
• 通讯作者: Wanket, Sean

Advances in seismic imaging of magma and crystal mush

• DOI: 10.3389/feart.2022.970131
• 发表时间: 2022-10
• 作者: M. Paulatto;E. Hooft;K. Chrapkiewicz;B. Heath;D. Toomey;J. Morgan

Heralds of Future Volcanism: Swarms of Microseismicity Beneath the Submarine Kolumbo Volcano Indicate Opening of Near‐Vertical Fractures Exploited by Ascending Melts

未来火山活动的先驱：科伦坡海底火山下方的微震群表明上升熔体所利用的近垂直裂缝的张开

• DOI: 10.1029/2022gc010420
• 发表时间: 2022
• 期刊: Geosystems
• 作者: Schmid, F.;Petersen, G.;Hooft, E.;Paulatto, M.;Chrapkiewicz, K.;Hensch, M.;Dahm, T.
• 通讯作者: Dahm, T.

Metamorphic bedrock geometry of Santorini using HVSR information and geophysical modeling of ambient noise and active-source surface-wave data

使用 HVSR 信息以及环境噪声和主动源表面波数据的地球物理建模研究圣托里尼岛的变质基岩几何形状

• DOI: 10.1016/j.jvolgeores.2022.107692
• 发表时间: 2022
• 期刊: Journal of Volcanology and Geothermal Research
• 影响因子: 2.9
• 作者: Chatzis, Nikos;Papazachos, Costas;Theodoulidis, Nikos;Hatzidimitriou, Panagiotis;Vougioukalakis, Georgios;Paulatto, Michele;Heath, Ben;Hooft, Emilie;Toomey, Douglas;Anthymidis, Marios
• 通讯作者: Anthymidis, Marios

Relationship Between Active Faulting/Fracturing and Magmatism Around Santorini: Seismic Anisotropy From an Active Source Tomography Experiment

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

• DOI: 10.1029/2021jb021898
• 发表时间: 2021
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Heath, B. A.;Hooft, E. E. E.;Toomey, D. R.;Paulatto, M.;Papazachos, C. B.;Nomikou, P.;Morgan, J. V.
• 通讯作者: Morgan, J. V.