HYDROTHERMAL CONTROLS ON CALDERA EXPLOSIVITY

火山口爆炸的热液控制

• 批准号: NE/X01519X/1
• 负责人: Isobel Yeo
• 金额: $ 128.9万
• 依托单位: NATIONAL OCEANOGRAPHY CENTRE
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX01519X%2F1
• 关键词: HYDROTHERMAL; CONTROLS; CALDERA; EXPLOSIVITY

Almost all active caldera volcanoes host hydrothermal systems that circulate a mixture of seawater, meteoric water and magmatic fluids through the subsurface geology to seeps or vents on the seafloor. These fluids can explosively interact with magma in volcanic eruptions and can change the physical properties of their host rocks, influencing both the likelihood of eruptions occurring and their explosivity. The nature of these interactions is poorly understood, including how fluid flow changes during periods of magmatic intrusion, how the hydrothermal system connects magmatic fluids to the surface and the spatial distribution and extent of alteration/mineralisation. While we know hydrothermal fluid flow plays an important role in modulating eruption dynamics, as long as these fundamental knowledge gaps exist it is impossible to forecast, with any degree of accuracy, what this effect will be which makes understanding hazards and impacts in eruption scenarios difficult. In this proposal we will combine novel controlled source electromagnetic mapping of porosity and permeability, with passive seismic mapping of hydrothermal fluid flow in the shallow subsurface, constrained by heat flow measurements and surface and subsurface sampling to characterise the porosity and permeability of the Santorini hydrothermal system. Santorini has been selected as the ideal natural laboratory to test these relationships because it is exceptionally well characterised geophysically and geologically, has a diversity of hydrothermal vents and has experienced recent activity which can be used to test modelling. We will quantify how magmatic fluids are partitioned between vents to identify the primary pathways for magmatic volatile escape, and quantify the impact hydrothermal mineralisation has had on the physical strength of the seafloor. Once we have a full picture of the system in its current state we will use mapping, fluid inclusions, mineralogy and the sedimentary record to establish how vent locations, subsurface fluid pathways, and fluid fluxes, temperatures and chemistries responded to the 2011/12 period of unrest. These data will be used to constrain the boundary conditions for a hydrothermal system model, which can be used to predict how the system will respond to future periods of intrusion both at Santorini and at other caldera systems around the world. This project will provide a step change in our understanding of hydrothermal interactions with volcanoes and our ability to predict their response to changes in the magmatic system. This has implications not just for understanding volcanic eruptions, but also for understanding metal and volatile fluxes from the mantle to the ocean and atmosphere, the development of economic metal deposits in these systems, the impact on ecological communities of intrusive and extrusive volcanic events, geothermal energy production, and for hazard forecasting and mitigation. The project will push the frontiers of knowledge by combining cutting edge geophysical and geochemical techniques to produce a model of a caldera hydrothermal system at a resolution previously not possible, and by developing modelling tools that would allow the application of these findings to other systems. The project is ambitious but achievable and benefits from a large team of international expert proponents, partnerships with other large international projects and high-quality pre-existing data upon which to build.

几乎所有活跃的火山口火山都有水热系统，这些系统将海水，陨石水和岩浆流体的混合物通过地下地质的混合物循环到海底的地下地质。这些流体可以在火山喷发中与岩浆爆炸性地相互作用，并可以改变其宿主岩石的物理特性，从而影响喷发的可能性发生及其爆炸性。这些相互作用的性质知之甚少，包括在岩浆入侵期间流体流动如何变化，水热系统如何将岩浆流体连接到表面以及空间分布以及改变/矿化的程度。尽管我们知道水热流体流在调节喷发动力学中起着重要作用，但只要存在这些基本知识差距，就无法以任何准确性预测，这种效果将使理解危害和影响的影响很困难。在此提案中，我们将结合新型受控的孔隙率和渗透率的电磁映射，以及浅层地下中热液流体流动流的无源地震映射，受热流量测量以及表面和地下采样的约束，以表征Santorini Hypothermalmal的孔隙度和渗透率。 Santorini已被选为测试这些关系的理想天然实验室，因为它在地质和地质上的特征表现出色，具有多种水热通风孔，并且经历了最近的活动，可用于测试建模。我们将量化岩浆流体在通风孔之间的分配方式，以识别岩浆挥发性逃逸的主要途径，并量化水热矿化对海底物理强度的影响。一旦我们对系统的当前状态进行了完整的了解，我们将使用映射，流体包含，矿物学和沉积记录来确定排气位置，地下流体途径以及流体通量，温度和化学物质如何应对动荡的2011/12时期。这些数据将用于限制水热系统模型的边界条件，该模型可用于预测该系统将如何应对圣托里尼岛和世界其他Caldera系统的未来入侵时期。该项目将为我们理解与火山的水热相互作用以及我们预测其对岩浆系统变化的反应的能力提供一步变化。这不仅具有理解火山喷发的意义，而且还旨在了解从地幔到海洋和大气的金属和挥发性通量，这些系统中经济金属沉积物的发展，对侵入性和额外的火山事件的生态社区的影响，地热能生产以及危害预测和危害预测和减轻。该项目将通过结合尖端地球物理和地球化学技术来推动知识的前沿，以以前不可能的分辨率以及开发允许将这些发现应用于其他系统应用的建模工具，从而生成火山口水热系统的模型。该项目雄心勃勃，但可以实现，并从一大批国际专家支持者，与其他大型国际项目的合作伙伴关系以及可以建立的高质量的预先存在数据中受益。