EAR-PF: Short fuses: investigating recent phreatic eruptions at Whakaari, New Zealand, through poroelastic modeling

EAR-PF：短熔丝：通过多孔弹性模型调查新西兰法卡里最近的潜水喷发

• 批准号: 2204527
• 负责人: John Albright
• 金额: $ 18万
• 依托单位: Albright, John A
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2204527&HistoricalAwards=false
• 关键词: EAR; PF; Short; fuses; investigating

Despite many recent advances in volcano monitoring, unforeseen volcanic eruptions pose a major hazard to human life and property around the world. Beyond the direct threat to the volcano’s immediate surroundings, ash clouds from such events can have far-reaching consequences, contaminating water supplies and rendering large sections of airspace unusable to commercial or defense traffic. Moreover, even foreign volcanoes can endanger American lives, given their popularity as tourist destinations. For example, the December 2019 eruption of Whakaari (White Island) in New Zealand left 5 American citizens dead and wounded 4 others. As with many deadly eruptions in recent history, this event was “phreatic”, driven primarily by the explosive release of shallow superheated steam rather than by the direct action of deeper magma. Such eruptions tend to occur suddenly; in many cases local monitoring networks do not observe any clear or reliable indication that an explosion is imminent. In these scenarios, local authorities are unable to evacuate the area, leading to significant casualties even from relatively small eruptions. Using Whakaari as a case study, this project will combine sophisticated computer simulations with years of monitoring data, spanning 3 eruptions, to investigate the volcano’s longer-term evolution. In particular, it seeks to study how non-eruptive activity at Whakaari may have predisposed or primed the system for the observed explosions. Ultimately, this process will deepen the scientific understanding of phreatic eruptions in general, beyond just Whakaari, and will allow these volatile events to be forecasted more reliably, even in the absence of immediate warning signs.The first stage of this project will synthesize previous advances in numerical modeling to develop a finite element simulation capable of fully capturing the poroelastic interactions between a volcano’s shallow hydrothermal system, from which phreatic eruptions are most often triggered, and the surrounding host rock. By combining the physics of fluid flow with those of rock deformation, this model will be able to predict how the volcano would mechanically respond to different configurations of permeability and magma influx. The second phase of the study would then use statistical data assimilation techniques to compare these predictions against measurements of ground deformation at Whakaari, finding the sets of underlying conditions that best match the volcano’s observed behavior. These models can then be further constrained and validated by comparing their predictions against additional seismic and geochemical observations. In the end, this project aims to test the hypothesis that Whakaari’s eruptions were caused by the mechanical rupture of low-permeability hydrothermal seals which had caused the slow accumulation of pressure in the months to years beforehand. Additionally, it will determine whether the modeled stress state of the system would have been sufficient to cause seal failure alone, or if an additional external trigger was required. By considering phreatic eruptions in the context of a volcanic system’s longer-term mechanical evolution, this study will help to understand how there events are triggered, what precursory activity may occur beforehand, and why certain precursors may be present for some eruptions but not others.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.

尽管最近的火山监测取得了许多进展，但不可预见的火山喷发对世界各地的人类生命和财产构成了重大危害。除了对火山周围环境的直接威胁之外，此类事件中的灰云还会带来深远的后果，污染水供应，并使大部分空域无法使用商业或国防交通。此外，鉴于它们作为旅游目的地的知名度，即使是外国火山也可能危及美国的生命。例如，2019年12月在新西兰的瓦卡里（Whakaari）爆发使5名美国公民受伤，并受伤了4人。与最近历史上的许多致命爆发一样，这一事件是“ phreatic”，这是由爆炸性的过热蒸汽的爆炸性释放而不是由更深的岩浆的直接动作驱动的。这种爆发往往突然发生。在许多情况下，本地监测网络没有观察到爆炸即将发生的任何明确或可靠的迹象。在这些情况下，地方当局无法撤离该地区，即使是从相对较小的喷发中也导致了重大伤亡。该项目将Whakaari作为案例研究，将复杂的计算机模拟与多年的监测数据结合在一起，涵盖3次喷发，以研究火山的长期演变。特别是，它试图研究瓦卡里（Whakaari）的非爆发活性如何使或启动了观察到的爆炸系统。最终，这个过程将加深对一般而言的卑鄙爆发的科学理解，超越了whakaari，即使没有立即的警告信号，这些波动性事件也可以更可靠地预测，即使没有立即的警告信号。该项目的第一个阶段将在数值模型中综合效率上的系统互动，从而完全捕获了一个有限的模型，可以完全捕获有限的系统，从而完全捕获了一个有限的彩绘，从而完全捕获了一个充分的伏击效果。最常见的爆发是最常触发的，周围的宿主岩石。通过将流体流的物理与岩石变形的物理相结合，该模型将能够预测火山如何机械响应渗透性和岩浆影响的不同构型。然后，该研究的第二阶段将使用统计数据同化技术将这些预测与瓦卡里（Whakaari）地面变形的测量进行比较，发现最适合火山观察到的行为的基本条件集。然后，可以通过将其预测与其他地震和地球化学观察结果进行比较，从而进一步限制和验证。最后，该项目旨在检验以下假设：瓦卡里（Whakaari）的喷发是由低渗透性氢气密封剂的机械破裂引起的，这在事先到几年之前导致压力缓慢。此外，它将确定系统的建模应力状态是否足以单独导致密封故障，或者是否需要额外的外部扳机。通过在火山系统的长期机械演化的背景下考虑短爆爆发，这项研究将有助于了解事件是如何触发的，可能事先发生的预先活动，以及某些爆发可能出现某些先驱者而不是其他奖励的原因，而其他奖项则反映了NSF的法定任务并通过评估的构想来诚实地审查了构成群体的范围。