Observing conduit flow processes during Strombolian Eruptions using Transient Electromagnetics (TEM): a numerical and field approach

使用瞬态电磁学 (TEM) 观察斯特龙博利火山喷发期间的管道流动过程：数值和现场方法

• 批准号: 434373481
• 负责人: Professor Dr. Matthias Hort
• 金额: --
• 依托单位: Institut für Geophysik (IfG)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/434373481?language=en
• 关键词: Observing; conduit; flow; processes; during

Volcanic eruptions are one of the most fascinating spectacles that can be witnessed on Earth. They are boon and bane to mankind and mitigating the effects of volcanic eruptions is a major societal task. Among other things mitigation strategies involve short term crisis management including short notice eruption warnings. Most crucial in this regard is the understanding of processes inside volcanic conduits preceding an eruption. In situ observations of magma transport processes in the conduit are still nearly impossible. So far almost all measurements rely on remote sensing techniques like seismological observations, tilt measurements or ground based InSAR observations. All processes in the conduit prior to an eruption involve the nucleation and growth of bubbles. In case of strombolian eruptions these bubbles are usually quite elongated with a length to width ratio being much larger than 1. They are called gas slugs. One of the goals of this proposal is to explore the potential of transient electromagnetics (TEM) to monitor the final rise of such gas slugs in the volcanic conduit passing through the last 100 m prior to the eruptions. Electromagnetic methods in general show a high potential in volcanic environments due to inductive coupling and the high conductivity contrast between magma, gas and host rock. By running virtual experiments using a highly sophisticated three-dimensional TEM forward simulation software we will explore the sensitivity of the subsurface response taking especially into account real topography and subsurface features like hydrothermal systems as well as a magma filled conduit including a gas slug. We will investigate the effect of various setups including different source/receiver configurations on the TEM response in a realistic volcanic setting. This will allow us to determine characteristic signals that we would expect to record at an active volcano using TEM prior to an eruption. In order to do so, we will expand an existing software with an adaptive meshing and sophisticated geomodeling tools to properly describe the volcanic edifice leading to novel modeling techniques and results in geoelectromagnetics.Applying a detailed sensitivity study using geophysical information available for Stromboli volcano, Italy, we will carry out a set of virtual experiments to constrain possible measurement configurations to optimize a field experiment at Stromboli. We propose to carry out a field experiment using TEM for monitoring processes within the volcanic conduit. These TEM measurements will be complemented by monitoring the eruptions using cameras and Doppler radar. Combining those data hopefully enables us to better constrain slug rise and benchmark numerical models for the rise of gas slugs in volcanic conduits thereby improving volcanic hazard mitigation.

火山喷发是地球上可以目睹的最迷人的奇观之一。它们对人类来说是布恩，也是祸害，减轻火山爆发的影响是一项重大的社会任务。除其他事项外，缓解战略涉及短期危机管理，包括短期通知火山爆发警告。在这方面，最关键的是了解火山爆发前火山管道内部的过程。在管道中的岩浆运输过程的现场观测仍然几乎是不可能的。到目前为止，几乎所有的测量都依赖于遥感技术，如地震观测、倾斜测量或地面干涉合成孔径雷达观测。喷发前管道中的所有过程都涉及气泡的成核和生长。在斯特龙博利喷发的情况下，这些气泡通常是相当细长的，长宽比远大于1。它们被称为气栓。该提案的目标之一是探索瞬变电磁学（TEM）的潜力，以监测火山管道中通过喷发前最后100米的这种气体段塞的最终上升。由于感应耦合以及岩浆、气体和寄主岩石之间的高电导率对比，电磁方法通常在火山环境中显示出很高的潜力。通过使用高度复杂的三维TEM正演模拟软件运行虚拟实验，我们将探索地下响应的灵敏度，特别考虑到真实的地形和地下特征，例如热液系统以及包含岩浆的充满导管。气体段塞。我们将调查各种设置的效果，包括不同的源/接收器配置上的TEM响应在一个现实的火山设置。这将使我们能够确定特征信号，我们希望记录在一个活火山喷发前使用TEM。为了做到这一点，我们将扩展现有的软件与自适应网格和复杂的geomodeling工具，以正确地描述火山editism. Application详细的敏感性研究，使用地球物理信息的斯特龙博利火山，意大利，我们将进行一组虚拟实验来限制可能的测量配置，以优化斯特龙博利的现场实验。我们建议进行现场实验，使用TEM监测过程中的火山管道。这些TEM测量将通过使用相机和多普勒雷达监测喷发来补充。结合这些数据，希望使我们能够更好地约束段塞上升和基准的火山管道中的气体段塞上升的数值模型，从而改善火山灾害的缓解。