Collaborative Research: Size, depth and longevity of magma reservoirs under Kilauea's rift zones: Integrating melt inclusion data and thermal modeling

合作研究：基拉韦厄裂谷带下岩浆储层的大小、深度和寿命：整合熔体包裹体数据和热模拟

• 批准号: 2020049
• 负责人: Paul Wallace
• 金额: $ 4.07万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-15 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2020049&HistoricalAwards=false
• 关键词: Collaborative; Research; Size; depth; longevity

Kilauea (Hawai'i) is one of the world’s most active volcanoes. The volcano erupted continuously for 35 years between 1983 and 2018 covering a vast area and burying several communities. The activity that started in May 2018 marked the first time that lava erupted this far east of the summit of Kilauea since 1960, and it led to great anguish for the local population, authorities, and government monitoring agencies. The communities of Leilani Estates, Lanipuna Gardens, Kapoho, and Vacationland (a total of 715 homes) were successively covered by lava flows and tephra, before effusion mostly stopped in August 2018. This eruption stood out in terms of sheer volume, erupting the equivalent of 8 years of prior activity within just a 3-month timeframe. Chemical analyses of the May 2018 lava revealed the anomalous composition of the first lavas: they were not recently supplied to the volcano’s summit magma plumbing system, as normally occurs, but instead had been stored for decades or longer directly underneath those communities located on the eastern flanks of Kilauea. These stored magma pockets slowly cooled and evolved in composition through time, generating no recognizable seismic activity or volcanic gas releases. This collaborative project combines expertise from six different institutions and will investigate the chemical properties of lavas erupted at this site in 2018 and in older nearby eruptions (1790, 1840, 1955, 1960) to determine how long magma pockets can stay in eruptible form within these regions, and at what depths they likely reside. This information will be crucial in the years to come to better understand and inform the local population about hazardous phenomena for the Island of Hawai'i. A 3-day long workshop in Hilo (Hawai'i) involving 8 senior scientists, two graduate students, and a number of undergraduate students from two local universities will seek to communicate new information stemming from this project to academics and the public. Participation in K-12 activities in schools near the 2018 eruption site are proposed not only to offer background information on Kilauea hazards, but also for academics and researchers to gain deeper insight about the effects such eruptive crises have on local populations.In detail, this project proposes to characterize droplets of melt that are trapped within crystals (olivine, pyroxene, plagioclase) during their growth in these older stored pockets of magma. These melt droplets (melt inclusions) preserve key chemical information about the stored magmas before they become modified by mixing with other magmas like in 2018. Chemical fingerprinting of the magma characteristics through different eruptions will help us understand whether these magmas are linked through time, and give first insights on their longevity within the lower east rift zone of Kilauea Volcano. Because melt inclusions also trap volatiles (H2O, CO2, S) whose concentrations depend directly on the depth of magma storage, quantifying these concentrations can be used to reconstruct storage pressure and depth of these magma pockets. Finally, three dimensional numerical models of cooling of magma bodies of different sizes and geometries under the rift zone will be combined with the geochemical information obtained to place tighter constraints on the timescales over which these magma pockets survive in eruptible form. At the time this project is starting, both Mauna Loa and Kilauea volcanoes show signs of magma input in their plumbing systems. Characterizing the complex subsurface magmatic structure of these shield volcanoes is therefore essential.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.

基拉韦亚（夏威夷）是世界上最活跃的火山之一。在1983年至2018年之间，火山连续爆发了35年，覆盖了一个广阔的地区并埋葬了几个社区。 2018年5月开始的活动标志着熔岩自1960年以来首次爆发了基拉韦阿峰会以东的遥远的东部，这引起了当地人口，当局和政府监督机构的极大痛苦。 Leilani Estates，Lanipuna Gardens，Kapoho和Vacationland（共有715户房屋）的社区成功地覆盖了熔岩和Tephra，然后Effussion主要在2018年8月停止了。这次喷发在纯粹的数量中脱颖而出，削弱了在3月的时间范围内的8年以内的8年活动。对2018年5月熔岩的化学分析揭示了第一个熔岩的异常组成：它们最近未提供给火山的山顶岩浆管道系统，因为通常发生，但已将其储存数十年或直接储存在位于Kilauea的东部侧面的社区之下。这些储存的岩浆口袋在随着时间的流逝中缓慢冷却和进化，不会产生可识别的地震活性或火山气释放。该协作项目结合了来自六个不同机构的专家，并将调查2018年该地点爆发熔岩的化学性能以及较旧的爆发（1790，1840，1955，1960），以确定岩浆口袋可以在这些地区内爆发多长时间，以及它们可能居住的深度。多年来，这些信息将至关重要，以便更好地理解并告知当地人口夏威夷岛的危险现象。在希洛（夏威夷）举办的为期3天的长期研讨会涉及8位高级科学家，两名研究生以及来自两所当地大学的许多本科生，将寻求将该项目的新信息传达给学者和公众。建议参与2018年喷发现场附近的学校的活动，不仅提议提供有关Kilauea危害的背景信息，而且还为学者和研究人员提供了对爆发危机对当地人群的影响的更深入的了解。在详细信息中，该项目的提议是为了表征液滴的液滴（olivine of pyrocient of pyroxene in pyroxene of pyroxene of pyroxene of pyroxene of pyroxene of pyroxene of pyroxene of pyroxene pyroc shisters pyrocece in of pyroxene pyroc oc的提议）岩浆。这些融化的液滴（融合夹杂物）通过与2018年（如2018年）混合在修饰的岩浆之前保留有关储存的岩浆的关键化学信息。化学指纹通过不同的喷发对岩浆特征进行化学指纹识别，这将有助于我们了解这些岩浆是否在时间上有联系，并在低下的East Rift of Kilauea of​​ Kilauea canuauea cano Cano Cano中的下降寿命。由于熔体夹杂物还捕获浓度直接取决于岩浆存储深度的熔融挥发物（H2O，CO2，S），因此可以使用这些浓度来重建这些岩浆口袋的储存压力和深度。最后，将在裂谷区下的不同大小和几何形状的岩浆体冷却的三维数值模型与获得的地球化学信息结合使用，以对这些岩浆口袋以可爆发形式存活的时间表放置更严格的约束。当时该项目开始时，Mauna Loa和Kilauea火山都在其管道系统中显示出岩浆输入的迹象。因此，表征这些盾牌火山的复杂地下岩浆结构是必不可少的。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评估标准来评估，被视为珍贵的支持。