Geochemical constraints on the source, flux, migration, and seismic signature of volcanic fluids, Katmai Volcanic Cluster, Alaska

活火山地下的流体运动通常被认为会产生大量的地震活动（即地震）；然而，流体的实际类型，包括岩浆、火山气体或热液，以及流体运动的影响，目前还不能从地震数据中得到限制。了解地下流体类型对于预测火山喷发和估计即将爆发的爆炸性都是至关重要的。通过比较火山气体成分和地震活动性的高时间分辨率测量，有可能确定与独特地震特征相关的流体类型。从地震数据中识别岩浆运动的能力将使科学家能够更好地确定即将爆发的可能性和/或时间。在这个项目中，火山流体的地球化学测量和阿拉斯加三座历史活跃火山的补充地震数据将用于：(1)确定火山气体的来源（即俯冲的板块、地幔、地壳）和通量，(2)确定地下岩浆和热液流体的比例，以及(3)区分与流体运动的地震特征相关的气体组成和/或通量趋势。气体成分将与总气体通量相结合，以帮助阐明俯冲和岩浆生成过程。每日测量的气体成分和通量将与两个月期间收集的地震数据进行比较，以帮助确定与某些地震信号相关的流体运动类型。这个项目将回答适用于地球地质系统目标的基础科学问题，特别是关于火山流体的储存、转移和释放，以及俯冲和地表过程之间的关系。

Fluid movement in the subsurface of active volcanoes is frequently thought to produce abundant seismicity (i.e. earthquakes); however the actual type of fluid, including magma, volcanic gases, or hydrothermal waters, and the implications of the fluid movement cannot currently be constrained from seismic data. Knowledge of the type of fluid/s in the subsurface is critical for both forecasting volcanic eruption and estimating the explosivity of the impending eruption. Through comparison of high temporal resolution measurements of volcanic gas composition and seismicity, it may be possible to identify the type of fluid associated with unique seismic signatures. The ability to identify magma movement from seismic data will enable scientists to better determine the likelihood and/or timing of impending eruptions. In this project, geochemical measurements of volcanic fluids and complementary seismic data from three historically-active Alaskan volcanoes will be used to: (1) determine the source (i.e. subducted slab, mantle, crust) and flux of volcanic gases, (2) determine proportions of magmatic and hydrothermal fluids within the subsurface, and (3) distinguish trends in gas composition and/or flux that correlate with seismic signatures of fluid movement. Gas composition will be combined with total gas flux to help elucidate subduction and magma generation processes. Daily measurements of gas composition and flux will be compared with seismic data collected over a two-month period to help determine the type of fluid movement associated with certain seismic signals. This project will answer fundamental science questions applicable to GeoPRISMS objectives, specifically regarding the storage, transfer, and release of volcanic fluids, and the relationship between subduction and surface processes.