Insights into Episodic Caldera Collapse and Magmatic Systems from the 2018 Eruption of Kilauea Volcano

从 2018 年基拉韦厄火山喷发洞察火山口火山口崩塌和岩浆系统

• 批准号: 2040425
• 负责人: Paul Segall
• 金额: $ 47万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-15 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2040425&HistoricalAwards=false
• 关键词: Insights; into; Episodic; Caldera; Collapse

Volcanic caldera collapse occurs when large volumes of magma erupt rapidly, causing the overlying the crust to founder into the subterranean magma chamber. Caldera collapse occurs during both explosive and lava flow forming eruptions; both are fortunately relatively rare. The 2018 eruption of Kīlauea volcano in Hawai‘i destroyed 700 homes and led to $800 million in damage. The associated caldera collapse was by far the best monitored in history. In 2.5 months, the floor of the centuries-old caldera, within Hawai‘i Volcanoes National Park, dropped up to 500 meters and increased in volume by 0.8 km3. It is crucial to understand the collapse process because the weight of the overlying crust acts to sustain these eruptions. While the basics of caldera collapse are understood, the unprecedented data collected in 2018 will allow us to address first order questions, including: What are the crustal stress and magma pressure conditions necessary for collapse? What is the sub-surface geometry of the ring fault system bounding the collapse? Why did collapse occur in discrete events, and what physical properties controlled the character of these events? What is the nature of sub-caldera magma storage systems and how do they connect to the eruptive vents? Modeling of these unique data will lead to a quantitative leap in our understanding of caldera collapse. The project will support a graduate student to understand volcanic hazards in the U.S.The 2018 collapse of occurred in 62 discrete events in which the caldera dropped from several to nearly 10 meters, accompanied by magnitude 5.2 to 5.4 earthquakes. Collapses were accompanied by remarkable, inflationary deformation offsets followed by decelerating deflations, similar to behavior at other basaltic caldera collapses. There has been considerable debate as to whether caldera ring-faults are inward or outward dipping. This project will use finite element (FEM) modeling combined with inversion of high-rate GPS data to constrain the ring-fault dip and the compressibility, and hence vesicularity, of the underlying magma. The research will further use pre- co-, and in particular post-collapse GPS and InSAR data to constrain the geometry, size and connectivity of the enigmatic summit magma system. The dynamics of collapse are analyzed with a model in which the weight of the caldera block is balanced by magma pressure at its base and rate-and-state dependent friction on its sides. Flow of magma is driven by the pressure difference between the magma chamber and the eruption site. Model predictions of repeated collapse events are compared to the time between events, their duration, displacement, and magma chamber pressure increase. The model elucidates the conditions for caldera collapse, and how collapse sustains eruptions that would otherwise cease. The measured surges in eruptive flux will be used to further constrain pressures within the magma system. Our analysis of co-collapse deformation leads naturally to a model for the VLP earthquakes. Synthetic waveforms will be computed that can be compared to low-pass filtered seismic observations. A striking correlation of cumulative VT seismicity with inter-collapse subsidence strongly suggests fault creep on the ring-fault prior to collapse, providing insights into fault development and chamber pressure history.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.

当大量的岩浆快速喷发时，火山口坍塌就会发生，导致覆盖在地壳上的岩浆流入地下的岩浆房。 火山口坍塌发生在爆炸和熔岩流形成的喷发过程中;幸运的是，这两种情况都相对罕见。 2018年，夏威夷的Kallauea火山爆发摧毁了700所房屋，造成8亿美元的损失。与之相关的破火山口坍塌是迄今为止历史上监测得最好的一次。 在2.5个月的时间里，夏威夷火山国家公园内有数百年历史的破火山口的底部下降了500米，体积增加了0.8立方公里。 了解崩塌过程是至关重要的，因为上覆地壳的重量起着维持这些喷发的作用。 虽然我们已经了解了破火山口坍塌的基本原理，但2018年收集到的前所未有的数据将使我们能够解决一阶问题，包括：坍塌所需的地壳应力和岩浆压力条件是什么？ 环绕崩塌的环形断层系统的地下几何形状是什么？为什么坍缩会发生在离散事件中，是什么物理性质控制了这些事件的性质？ 破火山口下岩浆储存系统的性质是什么？它们如何与喷发口相连？对这些独特数据的建模将使我们对破火山口坍塌的理解发生质的飞跃。该项目将支持研究生了解美国的火山灾害。2018年发生了62次不连续事件，其中火山口从几米下降到近10米，并伴有5.2至5.4级地震。 崩塌伴随着显著的膨胀变形抵消，随后是减速的收缩，类似于其他玄武岩破火山口崩塌的行为。 关于火山口环形断层是向内倾斜还是向外倾斜，一直存在相当大的争论。 该项目将使用有限元（FEM）建模结合高速率GPS数据的反演来约束环断层倾角和压缩性，从而限制底层岩浆的泡状。 该研究将进一步使用前的合作，特别是崩溃后的GPS和干涉合成孔径雷达数据，以约束的几何形状，大小和连接的神秘山顶岩浆系统。 崩溃的动力学分析模型中，火山口块的重量是平衡的岩浆压力在其基地和速率和状态依赖于其两侧的摩擦。 岩浆的流动是由岩浆房和喷发地点之间的压力差驱动的。 模型预测的重复崩溃事件之间的事件，其持续时间，位移和岩浆房压力增加的时间进行了比较。 该模型阐明了破火山口坍塌的条件，以及坍塌如何维持否则将停止的喷发。 测量到的喷发通量的激增将被用来进一步限制岩浆系统内的压力。我们对共塌变形的分析自然地导致了VLP地震的模型。 将计算合成波形，其可以与低通滤波的地震观测进行比较。 累积VT地震活动性与塌陷间沉降的显著相关性强烈表明了塌陷前环形断层上的断层蠕动，为断层发展和腔室压力历史提供了见解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Physics‐Based Model Reconciles Caldera Collapse Induced Static and Dynamic Ground Motion: Application to Kīlauea 2018

基于物理的模型协调了火山口塌陷引起的静态和动态地面运动：应用于 Kä«lauea 2018

• DOI: 10.1029/2021gl097440
• 发表时间: 2022
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Wang, Taiyi A.;Coppess, Katherine R.;Segall, Paul;Dunham, Eric M.;Ellsworth, William
• 通讯作者: Ellsworth, William

Repeating caldera collapse events constrain fault friction at the kilometer scale

• DOI: 10.1073/pnas.2101469118
• 发表时间: 2021-07
• 期刊: Proceedings of the National Academy of Sciences
• 作者: P. Segall;K. Anderson

Could Kı̄lauea's 2020 Post Caldera‐Forming Eruption Have Been Anticipated?

Kä±Ìlauea 2020 年火山口形成后的喷发是否已被预料到？

• DOI: 10.1029/2022gl099270
• 发表时间: 2022
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Segall, Paul;Anderson, Kyle;Wang, Taiyi A.
• 通讯作者: Wang, Taiyi A.

Post‐2018 Caldera Collapse Re‐Inflation Uniquely Constrains Kīlauea's Magmatic System

2018 年火山口崩塌后的通货膨胀再次制约了凯劳厄亚的岩浆系统

• DOI: 10.1029/2021jb021803
• 发表时间: 2021
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Wang, Taiyi;Zheng, Yujie;Pulvirenti, Fabio;Segall, Paul
• 通讯作者: Segall, Paul