Computational modeling of volcanic eruptions and their seismic and infrasound radiation

火山喷发及其地震和次声辐射的计算模型

• 批准号: 2231849
• 负责人: Eric Dunham
• 金额: $ 42.21万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-15 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2231849&HistoricalAwards=false
• 关键词: Computational; modeling; volcanic; eruptions; their

Explosive volcanic eruptions similar to the 1980 Mount Saint Helens eruption can be monitored from a safe distance using seismometers, which measure shaking of the ground, and microphones, which measure sound waves in the atmosphere. The overall goal of this project is to develop connections between shaking, sound waves, what’s going on inside a volcano and its eruption plume, and why explosive eruptions occur. One possibility is that the magma conduit gets blocked, leading to pressure build-up which eventually destroys the blockage and causes an eruption. The project team will develop computer simulations that track magma as it travels through the volcanic conduit (in some cases, having to break through blockages), becomes fragmented, and is discharged into the atmosphere. These simulations can predict sound waves and ground shaking generated by the eruption. Predictions from the models will be compared with data from the 2013-2014 explosive eruptions of Tungurahua volcano in Ecuador, which are probably the most powerful explosive eruptions ever recorded. This research will be done in partnership with the Instituto Geofisico in Ecuador, who will be providing data and expert knowledge of the eruptions. The project will provide training for two to three PhD students and several undergraduates, and all of the computer programs the team develops to simulate the eruptions will be freely shared with other scientists.This project develops models of seismic and infrasound radiation from vulcanian eruptions. The goal is to use seismic and infrasound data to quantify the depth of fragmentation, the forces associated with plug rupture at the onset of eruptions, the mass eruption rate and total erupted mass, and the vertical momentum exchange between the solid Earth and atmosphere. These are useful to understand fundamental processes involved in vulcanian eruptions (e.g., under what conditions does a plug form and what causes it to rupture) and to provide inputs to eruption plume modeling. The project builds on previous NSF-supported work by the project team that produced the theory and workflow to compute synthetic seismograms from unsteady conduit flow models. The project team is continuing work on an open-source code that couples conduit flow to a compressible atmosphere, thereby also providing predictions of infrasound radiation and the flow structure of the eruptive jet and plume. This overall modeling framework will be used for generic studies to understand processes as well as to study actual eruptions for which seismic and infrasound data are available. For the latter, the project team has partnered with the Insituto Geofisico, Ecuador, to model the well-recorded 2013-2014 eruption of Tungurahua volcano. An additional component of the project is a study of seismic eruption tremor (incoherent waves in the ~1-10 Hz band), a ubiquitous characteristic of explosive eruptions that in some cases is correlated with plume height. The project team will explore multiple hypotheses for eruption tremor, including turbulence and particle-wall interactions above fragmentation, as well as unsteadiness of the fragmentation process as magma with variable viscosity and other properties passes through the fragmentation depth. Finally, the project team is incorporating water (including phase changes) into their multiphase modeling code, giving them the ability to study the interaction of magma with groundwater and seawater, including submarine eruptions. The open-source codes and modeling workflows will be provided to the community for use by volcano observatories and other researchers.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.

可以使用地震仪从安全距离监测与1980年圣海伦斯山爆发相似的爆炸性火山喷发，该仪表仪测量地面的摇动和麦克风，并测量大气中的声波。该项目的总体目标是在摇晃，声波，火山内发生的事情和爆发羽流以及为什么发生爆炸性喷发之间建立联系。一种可能性是岩浆导管被阻塞，导致压力堆积，有时会破坏阻塞并引起喷发。项目团队将开发计算机模拟，以跟踪岩浆穿过火山导管时（在某些情况下，必须打破障碍物），变成碎片并将其排放到大气中。这些模拟可以预测喷发产生的声波和地面摇动。该模型的预测将与厄瓜多尔的Tungurahua火山的2013 - 2014年爆炸性爆发进行比较，厄瓜多尔可能是有史以来最强大的爆炸性喷发。这项研究将与厄瓜多尔的Geofisico合作进行，后者将提供有关喷发的数据和专家知识。该项目将为两到三个博士学位学生和几名本科生提供培训，并且团队开发以模拟喷发的所有计算机计划将与其他科学家免费共享。这项项目开发模型的地震和侵蚀辐射模型都来自瓦肯尼亚爆发。目的是使用地震和反射数据来量化碎片的深度，发作开始时与塞子破裂相关的力，质量喷发率和总爆发质量以及固体地球与大气之间的垂直动量交换。这些对于了解瓦坎尼亚喷发涉及的基本过程很有用（例如，在插头形式的哪些条件下以及导致其破裂的原因）并为喷发羽流建模提供了投入。该项目建立在项目团队的先前NSF支持的工作的基础上，该项目产生了理论和工作流程，以计算不稳定的导管流模型的合成地震图。该项目团队正在继续使用开源代码进行工作，该代码将导管融合到可压缩的气氛中，从而提供了基础设施辐射的预测以及喷射和羽流的流动结构。该总体建模框架将用于通用研究，以了解过程以及可提供地震和不向反向数据的实际喷发。对于后者，项目团队与厄瓜多尔的Insituto Geofisico合作，为Tungurahua火山的2013 - 2014年爆发进行了建模。该项目的另一个组成部分是对地震喷发树的研究（〜1-10 Hz带中的不相干波），这是爆炸性喷发的无处不在的特征，在某些情况下与羽状高度相关。该项目团队将探索喷发树的多个假设，包括碎片上方的湍流和颗粒壁相互作用，以及碎片化过程的不稳定，作为具有可变粘度和其他特性的岩浆，都穿过碎片深度。最后，项目团队将水（包括相变）增加到其多相建模代码中，使他们能够研究岩浆与地下水和海水的相互作用，包括潜艇喷发。开源法规和建模工作流将提供给社区，以供火山观察家和其他研究人员使用。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响审查标准来评估，认为NSF的法定任务是珍贵的支持。