Constraining Transcrustal Magmatic Systems with Receiver Functions Along the Aleutian Island Arc

使用阿留申岛弧沿线的接收器函数约束穿地壳岩浆系统

• 批准号: 2052829
• 负责人: Helen Janiszewski
• 金额: $ 29.6万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2052829&HistoricalAwards=false
• 关键词: Constraining; Transcrustal; Magmatic; Systems; Receiver

The subterranean plumbing system beneath volcanoes is still not well understood. Recent advances in the understanding of crustal magmatic storage reveal them as complex, multi-layered systems consisting of both melt and crystal mush. However, it remains unclear how magma is stored and transported from the Earth’s mantle through the crust at volcanic arcs. A volcanic arc is a chain of volcanoes located above a subducting tectonic plate, i.e., a plate diving underneath another. Magmatic systems at arc volcanoes are a critical link between the subducting slab and the shallow magma reservoirs that feed volcanic eruptions. However, many established methods of constraining depth of magma storage have relatively low resolution in the mid-to-deep crust. Receiver functions are a technique of seismic imaging relatively underutilized in volcanic settings. They have recently shown promise in their ability to image magma storage in the deep crust. Here, the researchers apply this technique to image the magmatic system beneath volcanoes in the Aleutian Island arc, in Alaska. Using state-of-the-art seismic analysis, they gradually unveil the complexity of volcanoes’ plumbing system. This study also contributes to developing an imaging technique that can be applied to other volcanoes around the Globe. The project’s outcomes improve volcanic hazard assessment in Alaska where eruptions threaten local populations and air traffic. Indeed, its primary target volcanoes are classified as Highest Priority or High Priority for monitoring by the National Volcano Early Warning System. The project also provides support for an early-career female scientist. It fosters training in volcano seismology to graduate and undergraduate students at University of Hawaii. This project is jointly funded by the Geophysics program, and the Established Program to Stimulate Competitive Research (EPSCoR).Here, the researchers conduct novel receiver function analysis of seismic data to constrain the crustal magmatic structure beneath a transect of volcanoes along the Aleutian Island arc. They calculate P-to-s receiver functions using existing broadband data to determine crustal seismic velocity models with primary sensitivity in the mid- to deep-crust (≥ 10 km depth). They focus on six Aleutian volcanoes - Okmok, Makushin, Akutan, Westdahl, Pavlof, and Shishaldin - and incorporate previous results from Cleveland Volcano. Receiver functions are well suited to detect low velocity regions in the crust, which can indicate magma storage. This transect samples variations in depth to slab, H2O content, volcanic seismicity distribution, and overriding crustal properties; these factors have been hypothesized to relate to variations in magmatic storage and transport beneath arc volcanoes. The team also calculate receiver functions along a secondary transect in the Western Aleutians (Gareloi, Tanaga, Kanaga, Great Sitkin, Korovin); while significantly less data is available, this gives a basis for future expansion of the technique across the Alaska-Aleutian arc. This project provides new constraints on the depths and structure of magmatic storage throughout the crust beneath the volcanoes. It enables investigation into the sources of variation in volcanic behavior along arcs. Through collaboration with the Alaska Volcano Observatory (AVO), the team utilizes these results to identify future monitoring and research needs in the Aleutians.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.

火山下方的地下管道系统仍然没有得到很好的了解，对地壳岩浆储存的理解的最新进展表明它们是由熔体和晶体糊组成的复杂的多层系统，但目前仍不清楚岩浆是如何储存和运输的。火山弧处的地幔穿过地壳，火山弧是位于俯冲构造板块上方的一系列火山，即一个板块潜入另一个板块下方的火山弧。火山是俯冲板块和火山喷发的浅层岩浆储层之间的关键环节。然而，许多现有的限制岩浆储存深度的方法在中深层地壳接收函数中的分辨率相对较低。他们最近在对地壳深处的岩浆储存进行成像的能力方面相对未得到充分利用，研究人员应用这种技术对阿留申群岛火山下方的岩浆系统进行成像。阿拉斯加的岛弧。他们利用最先进的地震分析，逐渐揭示了火山管道系统的复杂性，这项研究也有助于开发一种可应用于全球其他火山的成像技术。成果改善了阿拉斯加的火山灾害评估，该地区的火山喷发威胁着当地居民和空中交通。事实上，其主要目标火山被国家火山早期预警系统列为最高优先级或高优先级监测。该项目由地球物理学项目和刺激竞争研究既定项目 (EPSCoR) 联合资助，旨在促进夏威夷大学研究生和本科生的火山地震学培训。对地震数据进行接收函数分析，以约束阿留申岛弧火山断面下方的地壳岩浆结构。他们使用现有的宽带数据计算 P-to-s 接收函数，以确定地壳。主要灵敏度为中深地壳（≥ 10 公里深度）的地震速度模型，重点关注六座阿留申火山 - Okmok、Makushin、Akutan、Westdahl、Pavlof 和 Shishaldin - 并结合了克利夫兰火山接收器之前的结果。函数非常适合检测地壳中的低速度，这可以指示岩浆储存情况，该样线样本的深度变化、H2O 含量、火山。地震活动分布和重要的地壳特性；这些因素已被探索与弧火山下方岩浆储存和运输的变化相关，该团队还计算了西阿留申群岛（加雷洛伊、塔纳加、卡纳加、大锡特金、 Korovin）；虽然可用数据显着减少，但这为未来在阿拉斯加-阿留申岛弧上扩展该技术奠定了基础，该项目对整个岩浆储存的深度和结构提供了新的限制。通过与阿拉斯加火山观测站 (AVO) 的合作，该团队可以利用这些结果来确定阿留申群岛未来的监测和研究需求。该奖项反映了美国国家科学基金会 (NSF) 的贡献。法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。