CAREER: Days before eruption: Tracking magma ascent pathways with a water-in-feldspar crystal clock

科学家监测火山的地震活动，以评估火山危险并预测喷发。很难预测火山喷发，部分原因是我们没有完全了解火山地震活动的起源。斯珀尔火山(位于阿拉斯加)的三次喷发之前都有有趣的地震信号。该项目的研究人员将通过研究喷发前几天岩浆的迁移路径来调查这些地震信号的来源。这项拟议的工作将使用喷发的火山灰晶体中的水的梯度来追踪岩浆在地壳中的迁移。这项工作的成果将在一年一度的火山暑期学校与当地高中生分享。在这个暑期学校，学生和未来的K-12科学教师将学习火山和火山灾害。这个暑期班的课堂练习将与现在和未来的K-12科学教师分享。长石中的水有可能成为晴雨表和计时器，用于跟踪富含水的岩浆在喷发前几个小时到几周内的迁移和停滞。然而，可用于评估水在长石中的分配和扩散行为的数据有限。这项拟议的工作将为探索水在斜长石中的分配和扩散提供新的实验，这些实验将作为水浓度、主要和微量元素组成以及氧逸度的函数。三次地球物理监测的火山喷发的斜长石上的水浓度梯度。然后，Spur将被用来评估岩浆在喷发前几小时到几天内的上升路径。这些岩浆迁移的岩石学限制将与火山动荡的地球物理记录进行比较，使我们能够检验关于这些重大喷发前几天岩浆阶段的相互矛盾的假说。拟议的工作提供了从高中到研究生的完整教育途径：高中生(来自少数民族入学率90%的当地学校)和未来的STEM教师将参加马里兰大学(UMD)一年一度的火山暑期学校；本科生研究人员将领导从1992年环形山喷发样本中获取和解释地球化学数据；一名研究生将领导实验研究。拟议工作的成果将以数据驱动练习的形式纳入UMD班级和火山暑期学校。这些练习将在网上分享，并与未来的STEM教育工作者分享，参与的学生将作为火山暑期学校的付费助教，参加UMD的“Terrapin教师”项目。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Scientists monitor seismicity at volcanoes to assess volcanic hazard and to forecast eruptions. It is difficult to forecast eruptions, in part because we do not fully understand the origin of volcano seismicity. Three eruptions of Mount Spurr (in Alaska) were preceded by interesting seismic signals. Investigators on this project will investigate the origin of these seismic signals by studying the migration pathways of magma in the days before the eruptions. The proposed work will track magma migration through the crust using gradients of water in crystals from the erupted volcanic ash. Results of this work will be shared with local high school students at an annual Volcano Summer School. At this summer school, students and future K-12 science teachers will learn about volcanoes and volcanic hazards. Classroom exercises created for this summer school will be shared with current and future K-12 science teachers.Water in feldspar has potential as a barometer and chronometer for tracking the migration and stalling of water-rich magmas in the hours to weeks prior to eruption. However, limited data is available for assessing the partitioning and diffusion behavior of water in feldspar. The proposed work would contribute new experiments that would explore water partitioning and diffusion in plagioclase feldspar as a function of water concentration, major and trace element composition, and oxygen fugacity. Water concentration gradients across plagioclase from three geophysically monitored eruptions of Mt. Spurr would then be used to assess the ascent paths of magmas in the hours to days before their eruption. These petrologic constraints on magma migration will be compared to the geophysical record of volcanic unrest, enabling us to test competing hypotheses regarding the staging of magma in the days before these significant eruptions. The proposed work provides a complete educational pathway from high school to graduate school: high school students (from local schools with 90% minority enrollment) and future STEM teachers will participate in an annual Volcano Summer School at University of Maryland (UMD); undergraduate researchers will lead the acquisition and interpretation of geochemical data from samples of the 1992 eruptions of Crater Peak; and a graduate student will lead the experimental research. Results of the proposed work will be integrated into UMD classes and the Volcano Summer School in the form of data-driven exercises. These exercises will be shared online and with future STEM educators via the participation of undergraduate students from UMD’s “Terrapin Teachers” program as paid teaching assistants at the Volcano Summer School.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.