MAGMA: Magma Accommodation and Ground Movement Analysis

MAGMA：岩浆住宿和地面运动分析

• 批准号: NE/Y000110/1
• 负责人: Craig Magee
• 金额: $ 107.07万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FY000110%2F1
• 关键词: MAGMA; Magma; Accommodation; Ground; Movement

MAGMA will transform how we capture the complex geology beneath volcanoes within the numerical models of volcano ground movement that are used in eruption threat assessment; this will help drive significant improvements in forecasting eruptions, helping keep people safe and secure.Over 800 million people live near volcanoes. To keep people safe and secure, we need to reliably forecast when volcanic eruptions may occur and what their potential size, style, and hazards will be. However, because the geology and plumbing system dynamics beneath each volcano is unique, all volcanoes behaves differently, making it difficult to reliably forecast eruptions. As magma intrudes through the crust and accumulates, it often pushes up the overlying rock and Earth's surface. Ground movements at active volcanoes thus often herald eruption. We therefore monitor the surface elevation of volcanoes, using satellites and ground-based tools, to look for tell-tale ground movements related to magma build-up. Using sophisticated numerical models, we can estimate the amount and location of magma required to drive measured ground movement. These estimates of magma bodies provide crucial inputs for eruption forecasts as they constrain how close magma may be to the surface, its volume and pressure, and how fast it is moving. A key flaw of many ground movement models is that they assume the rocks through which magma moves are simple and have no internal structure or compositional variation. Yet we know rocks vary physically and chemically at all scales, and how they deform changes in space and time. Critically, ground movement models that include more realistic geology (e.g. layering) show that, incorporating even small degrees of complexity can change estimated magma body properties by orders of magnitude. Such changes in magma body estimates may be the difference between forecasting an eruption or not. Reliably using ground movement to forecast volcano eruption onset, size, style, and hazards requires models that realistically capture host rock complexity. For example, uplift above injecting magma requires the overlying rock to bend. Yet we actually know very little about how resistant rocks are to bending. We also do not know how local extension and compression within the bending rock volume changes its material properties and thus affects its response to further deformation. Critically, these controls on rock bending dictate how much and where ground movement occurs above injecting magma. To solve these problems in MAGMA, we will:1) Conduct mechanical experiments where we load and bend different rocks to measure their resistance to bending; lab results will be 'upscaled' using tried and tested geotechnical methods so they are representative of entire rock masses.2) Examine the geometry of and deformation within ancient areas of uplift above magma bodies exposed at the surface or imaged in 3D seismic reflection data, which provides ultrasound-like images of the subsurface.3) Collect samples from field areas and use mechanical experiments to pull and compress them in the lab to test how bending locally changed their resistance to deformation. MAGMA will use this information to build novel Finite Element numerical model that can capture multiple aspects of host rock complexity. These models will adopt a perturbation theory approach, which has been successfully tried and tested in complex ground movement models of earthquakes. With our developed method, we will create synthetic but realistic models of volcanic systems to simulate ground movement above pre-defined magma bodies. By incorporating host complexities and varying inputs, we will test different geological scenarios. Our work will enable a step-change in ground movement modelling, which will lead to improvements in the reliability of eruption forecasting and understanding of volcanic processes, helping keep people safe and secure.

岩浆将改变我们在火山地面运动数值模型中捕捉火山下面复杂地质的方式，这些模型用于喷发威胁评估；这将有助于推动预测喷发的重大改进，帮助确保人们的安全。超过8亿人生活在火山附近。为了保障人们的安全，我们需要可靠地预测火山喷发可能发生的时间以及潜在的规模、风格和危险。然而，由于每座火山下方的地质和管道系统动力学都是独一无二的，所有火山的行为都不同，因此很难可靠地预测喷发。当岩浆侵入地壳并积累时，它通常会将上覆的岩石和地球表面推高。因此，活火山的地面运动往往预示着火山喷发。因此，我们使用卫星和地面工具监测火山的表面高度，以寻找与岩浆聚集有关的可靠的地面运动。使用复杂的数值模型，我们可以估计驱动测量的地面运动所需的岩浆数量和位置。这些对岩浆体的估计为喷发预测提供了至关重要的信息，因为它们限制了岩浆可能离地表有多近，它的体积和压力，以及它移动的速度。许多地面运动模型的一个关键缺陷是，它们假设岩浆通过的岩石很简单，没有内部结构或成分变化。然而，我们知道岩石在所有尺度上都有不同的物理和化学变化，以及它们如何变形在空间和时间上的变化。关键是，包含更真实的地质学(例如分层)的地面运动模型表明，即使是包含很小程度的复杂性，也可以按数量级改变估计的岩浆体属性。岩浆体估计的这种变化可能是预测喷发或不喷发之间的差异。要可靠地使用地面运动来预测火山喷发的开始、规模、风格和危害，需要能够真实地捕捉到主岩复杂性的模型。例如，高于注入岩浆的隆起需要上覆岩石弯曲。然而，我们实际上对岩石的抗弯能力知之甚少。我们也不知道弯曲岩石体积内的局部拉伸和压缩如何改变其材料特性，从而影响其对进一步变形的响应。关键的是，这些对岩石弯曲的控制决定了在注入岩浆的上方发生了多少地面运动以及在哪里发生了移动。为了解决岩浆中的这些问题，我们将：1)进行力学实验，我们对不同的岩石进行加载和弯曲，以测量它们的抗弯性能；2)使用经过检验和测试的岩土工程方法，将实验室结果“放大”，使其能够代表整个岩块；2)研究地表裸露或在3D地震反射数据中成像的古代隆起区域的几何形状和内部变形，这将提供地下表面类似超声的图像。3)从野外采集样品，并在实验室使用力学实验对它们进行拉伸和压缩，以测试弯曲如何改变其局部抗形变能力。岩浆将利用这些信息建立新的有限元数值模型，该模型可以从多个方面反映围岩的复杂性。这些模型将采用摄动理论方法，这种方法已经在复杂的地震地面运动模型中得到了成功的尝试和测试。使用我们开发的方法，我们将创建合成的但现实的火山系统模型，以模拟预先定义的岩浆体上方的地面运动。通过结合主机的复杂性和不同的输入，我们将测试不同的地质场景。我们的工作将使地面运动模型发生阶段性变化，从而提高喷发预测的可靠性和对火山过程的理解，帮助确保人们的安全。