Gaining new insights into the magmatic and tectonic processes at Kilauea Volcano from analysis of data recorded by the 2018 RAPID OBS array

2018年，夏威夷基拉韦厄火山经历了一系列重大事件，包括超过500米的山顶坍塌，熔岩喷发，以及6. 9级地震及其多次余震。 这些事件的后果是对基础设施和财产的广泛破坏。2018年7月初，由NSF快速反应研究（RAPID）计划赠款资助的一个团队在基拉韦厄近海部署了12个海底地震仪（OBS）。十二个泡罩中的十一个已于九月中回收。除了一个外，所有恢复的OBS在整个记录期间都有有用的地震和水声数据。在两个月的OBS记录期间，美国地质调查局（USGS）夏威夷火山观测站（HVO）定位了大约16，000次1级及以上地震，其中许多发生在近海或海岸附近。由于所有的HVO地震台站都在陆地上，许多近海地震可能在USGS HVO目录中被遗漏或定位不佳。初步数据分析表明，OBS部署成功地捕获了大量余震活动的重要部分，并跨越了活跃熔岩喷发的终止。 这是第一次通过同时进行的陆上-海上地震台阵观测到这种事件，这些事件提供了一个非常好的机会，以极其丰富的细节和维度观察岩浆和构造过程之间的相互作用。 本项目旨在分析OBS数据，以更好地了解基拉韦厄火山的管道系统和故障。 这些分析将与美国地质勘探局夏威夷火山观测站、西华盛顿大学和赖斯大学的科学家合作完成。 该项目将对近海海洋观测站收集的数据进行分析，以获得对基拉韦厄火山岩浆和构造过程的新见解，重点关注四个主要科学问题：（1）在2018年的事件中，基拉韦厄南翼的哪些结构被激活，它们容纳了什么变形？(2)主要断层的物理性质是什么？(3)深层岩浆如何在空间和时间上迁移？（4）潜艇南翼的应力状态如何？ 这些是关于基拉韦厄火山和大洋盾状火山的岩浆和构造过程的长期问题。这些答案将提供对侧翼变形和深部岩浆迁移的限制，并将对地震灾害、海底滑坡和海啸风险产生影响。 数据分析将包括探测和定位地震，确定主要断层的物理特性和基拉韦厄南翼的应力状态。预期的结果包括一个近海地震目录和完善的近海速度模型，这将使开发，在美国地质勘探局的支持下，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进行评估，被认为值得支持的搜索.

In 2018, Kilauea Volcano, Hawaii underwent a series of major events including more than a 500-meter collapse of the summit, lava eruptions, and a magnitude 6.9 earthquake and its numerous aftershocks. The consequences of these events were extensive damage to infrastructure and property. In early July 2018, a team funded by the NSF Grants for Rapid Response Research (RAPID) program deployed 12 ocean bottom seismometers (OBSs) offshore Kilauea. Eleven of the twelve OBSs were recovered in mid-September. All but one of the recovered OBSs had useful seismic and hydroacoustic data for the full recording period. During the two-month OBS recording periods, around 16,000 magnitude 1 and larger earthquakes were located by the U.S. Geological Survey (USGS) Hawaiian Volcano Observatory (HVO), many occurring offshore or near the coast. Because all HVO seismic stations are on land, many offshore earthquakes were likely missed or poorly located in the USGS HVO catalog. Preliminary data analysis shows that the OBS deployment successfully captured a significant portion of abundant aftershock activity and spanned the termination of active lava eruption. It was the first time that such events are observed by concurrent onshore-offshore seismic arrays and these events provided an extraordinary opportunity to observe the interplay between magmatic and tectonic processes in exceptionally rich detail and dimension. This project is to analyze the OBS data to obtain a better understanding of the plumbing system and faults at Kilauea Volcano. The analyses will be done in collaboration with scientists at the USGS Hawaii Volcano Observatory, Western Washington University, and Rice University. The project supports the training of one graduate and two undergraduate students.In this project, we will analyze the data collected by the offshore OBSs to gain new insights into the magmatic and tectonic processes at Kilauea Volcano, focusing on four main scientific questions: (1) What structures within Kilauea's south flank were activated during the 2018 events, and what deformation did they accommodate? (2) What are the physical properties of the main faults? (3) How does deep magma migrate in space and time? And (4) What are the stress states of the submarine south flank? These are long-standing questions about the magmatic and tectonic processes at Kilauea Volcano and oceanic shield volcanoes in general. The answers will provide constraints on flank deformation and deep magma migration and will have implications for seismic hazards, submarine landslides, and tsunami risks. The data analyses will include detecting and locating earthquakes and determining the physical properties of major faults and stress states of the Kilauea south flank. The expected results include a catalog of offshore earthquakes and refined offshore velocity models, which will enable the development, with support by the USGS, of new offshore seismicity monitoring capabilities with the potential to enhance societal preparedness and resilience against such impacts.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.