Collaborative Research: From the Slab to the Surface: Origin, Storage, Ascent and Eruption of Volatile-Bearing Magmas

在任何一天，全世界大约有15 - 30座火山正在喷发或显示出强烈的动荡迹象（例如，地震活动、地面变形或气体排放的异常高的速率）。火山活动，包括高空火山灰喷发或大量气体排放，对美国和世界各地的人民和财产构成重大危险。在阿拉斯加尤其如此，每天有超过10，000名乘客在北美/亚洲航线上飞越35座历史上活跃的火山。虽然近几十年来在了解直接导致火山活动和相关动荡的地壳上部发生的物理过程方面取得了重大进展，但对这些浅地壳过程如何与最终导致弧火山作用的大规模地壳构造和深地幔熔融联系并受其控制，仍然缺乏基本的了解。具体来说，虽然人们很好地理解了溶解在岩浆中的水和其他挥发物的数量在其生成，上升和喷发中起着关键作用，但目前还不清楚为什么有些弧火山喷发的岩浆比其他火山更“湿”。因此，确定大规模的岩浆挥发性成分的控制是至关重要的频率，体积和火山爆发的爆炸性的准确预测。在这里，我们提出了一个综合的地球化学-地球物理研究的乌尼马克-克利夫兰走廊的阿留申火山弧，其中包括六个火山爆发，在过去的25年中，范围广泛的岩浆水含量。这个相对较小的走廊也表现出一系列的深部和上地壳地震活动，明显的岩浆储存深度，以及俯冲构造板块的深度。我们的目标是将两个通常不相关的大问题联系起来：1）岩浆和挥发物的深层起源，2）地壳岩浆库的形成和喷发，我们建议通过建立整个走廊的地壳岩浆库和喷发前挥发物含量的深度来实现。综合研究内容包括火山-地震事件分析和岩浆挥发性分析。现有的地震数据目录包含约14，000个事件，一些火山爆发产品的样本已经在手。走廊中两座活跃喷发的火山的存在进一步激发了在喷发期间同时收集地震、气体（与美国地质勘探局阿拉斯加火山观测站合作）和火山灰样品的动机，这些样品反映了岩浆系统的活跃演化。

On any given day, approximately 15-30 volcanoes worldwide are either in eruption or show strong signs of unrest (e.g., anomalously high rates of seismic activity, ground deformation, or gas emissions). Volcanic activity, including high-altitude eruptions of ash or emission of large volumes of gas, poses a significant hazard to people and property in the United States and worldwide. This is particularly true in Alaska, with over 10,000 passengers a day flying over 35 historically active volcanoes on North America/Asia flight routes. Although significant progress has been made in recent decades in understanding the physical processes occurring in the upper portions of the Earth's crust that lead directly to volcanic activity and associated unrest, there is a fundamental lack of understanding of how these shallow crustal processes link to and are controlled by the large-scale crustal tectonics and deep mantle melting that are ultimately responsible for arc volcanism. Specifically, although it is well understood that the amount of water and other volatiles dissolved in a magma plays a key role in its generation, ascent, and eruption, it is unclear why some arc volcanoes erupt 'wetter' magmas than others. Identifying large scale controls on magma volatile contents is thus critical for accurate forecasting of the frequency, volume, and explosivity of volcanic eruptions. Here, we propose an integrated geochemical-geophysical study of the Unimak-Cleveland corridor of the Aleutian volcanic arc, which encompasses six volcanoes that have erupted in the past 25 years with a wide range of magmatic water contents. This relatively small corridor also exhibits a range of deep and upper-crustal seismicity, apparent magma storage depths, and depths to the subducting tectonic plate. Our goal is to link two normally disconnected big-picture problems: 1) the deep origin of magmas and volatiles, and 2) the formation and eruption of crustal magma reservoirs, which we propose to do by establishing the depth(s) of crustal magma reservoirs and pre-eruptive volatile contents throughout the corridor. The integrated study components include analysis of volcano- seismic events and magmatic volatile analysis. Existing seismic data catalogs contain ~ 14,000 events, and some samples of volcanic eruption products are already in hand. The existence of two actively erupting volcanoes in the corridor further motivates collection of simultaneous seismic, gas (in collaboration with the USGS Alaska Volcano Observatory) and tephra samples during eruption, that reflect active evolution of the magmatic system.