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

火山下面的地下管道系统仍然没有很好的了解。最近的进展，在了解地壳岩浆储存揭示他们作为复杂的，多层次的系统，包括熔体和晶体糊。 然而，目前还不清楚岩浆是如何从地幔通过火山弧的地壳储存和运输的。火山弧是位于俯冲构造板块之上的火山链，即，一个板块俯冲到另一个板块之下 弧火山的岩浆系统是俯冲板块和供给火山爆发的浅岩浆库之间的关键联系。然而，许多已建立的限制岩浆储存深度的方法在地壳中深部的分辨率相对较低。接收器功能是一种地震成像技术，在火山环境中相对未得到充分利用。他们最近在对地壳深部岩浆储存成像的能力方面显示出了希望。在这里，研究人员应用这种技术来成像阿拉斯加阿留申岛弧火山下的岩浆系统。利用最先进的地震分析，他们逐渐揭示了火山管道系统的复杂性。 这项研究还有助于开发一种可应用于地球仪周围其他火山的成像技术。 该项目的成果改善了阿拉斯加的火山灾害评估，那里的火山爆发威胁到当地人口和空中交通。事实上，其主要目标火山被列为国家火山预警系统监测的最高优先或高度优先。该项目还为一名职业生涯初期的女科学家提供支助。它促进了对夏威夷大学研究生和本科生的火山地震学培训。该项目由地球物理计划和刺激竞争研究的既定计划（EPSCoR）共同资助。在这里，研究人员对地震数据进行新颖的接收器函数分析，以限制阿留申群岛弧沿着火山横断面下的地壳岩浆结构。 他们使用现有的宽带数据计算P-to-s接收器函数，以确定具有中地壳至深部（≥ 10 km深度）主要灵敏度的地壳地震速度模型。他们集中在六个阿留申火山-奥克莫克，马库欣，阿库坦，韦斯特达尔，帕夫洛夫和希沙尔丁-并纳入以前的结果从克利夫兰火山。接收器功能非常适合于检测地壳中的低速区域，这可以指示岩浆储存。该样带样本的深度变化板，H2O含量，火山地震活动分布，和压倒一切的地壳属性，这些因素已被假设为涉及到弧火山下的岩浆储存和运输的变化。 该团队还计算了沿着阿留申群岛西部（Gareloi，Tanaga，Kanaga，Great Sitkin，Korovin）的次级样带的接收器功能;虽然可用的数据明显较少，但这为该技术在阿拉斯加-阿留申群岛弧的未来扩展奠定了基础。该项目提供了新的限制的深度和结构的岩浆储存在整个地壳下的火山。它使人们能够调查火山活动沿着弧变化的来源。通过与阿拉斯加火山观测站（AVO）的合作，该团队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。

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.