Investigation of the hydrogeologic role of faults in the downgoing plate through comparison of Central America, Cascadia, Nankai, and Alaska subduction zones

通过比较中美洲、卡斯卡迪亚、南开和阿拉斯加俯冲带研究下降板块中断层的水文地质作用

• 批准号: 1457221
• 负责人: Nathan Bangs
• 金额: $ 25.7万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457221&HistoricalAwards=false
• 关键词: Investigation; hydrogeologic; role; faults; downgoing; Investigation; hydrogeologic; role; faults; downgoing

Part 1The award will fund a GeoPRISMS postdoctoral Fellowship for two years of training at the University of Texas, Institute for Geophysics (UTIG). The proposed work seeks to quantitatively determine the structure and water content in the faults within the select segments of the subducting plates. This will allow the assessment of the effects of subducting water on subduction zone processes. The study will use existing 2D and 3D multichannel seismic data from Central America, Cascadia, Nankai, and Alaska subduction zones. The results will provide a better understanding of the geohazard potential in subduction zones, which is particularly relevant for the Pacific Northwest region where large magnitude earthquakes have occurred on the Cascadia megathrust in recent history. The postdoctoral fellow is an early-career female scientist. The results of the study will be presented at workshops and conferences and will contribute to the high school curriculum development program at UTIG. Part 2Funds are provided for a postdoctoral fellow to conduct amplitude preserved seismic prestack depth migration, 2D waveform modeling of fault plane reflections, and fluid flow modeling of the 2D multichannel seismic data at Nicaragua, Cascadia, Nankai, and Alaska subduction zones to explore the limits on the water content of the fault zones in the oceanic plate seaward of the trench. From these results she will begin to quantitatively assess the hydration state of incoming plate at different subduction zones. The seismic attribute analysis of decollement, near-basement sediment, and basement crustal rocks, and the waveform modeling of the faults in the down-going plate beneath the slope in Nankai and Costa Rica 3D datasets will allow the assessment of fluid exchange between the hydrologic systems of upper and lower plate. The post-doctoral fellow will identify water expulsion along faults in the down- going plate as it migrates upward into the upper plate. The results from this study will contribute to answer the two key questions in the GeoPRISMS Subduction Cycles and Deformation science plan: "How are volatiles, fluids, and melts stored, transferred, and released through the subduction system?" and "How do volatile release and transfer affect the rheology and dynamics of the plate interface, from the incoming plate and trench through to the arc and backarc?"Broader Impacts: The proposed work will provide a better understanding of the geohazard potential in subduction zones, which is particularly relevant for the Pacific Northwest region where large magnitude earthquakes have occurred on the Cascadia megathrust in recent history. The project will support the postdoctoral training of an early-career female scientist. The results of the study will be presented at workshops and conferences and will contribute to the high school curriculum development program at UTIG.

第1部分该奖项将为德克萨斯大学地球物理学院（UTIG）的两年培训两年培训提供杂志博士后奖学金。拟议的工作旨在定量确定俯冲板部分断层中的结构和水含量。这将允许评估俯冲水对俯冲带过程的影响。该研究将使用来自中美洲，卡斯卡迪亚，南卡和阿拉斯加俯冲带的现有2D和3D多通道地震数据。结果将更好地了解俯冲带中的地球扎下潜力，这与西北太平洋地区特别相关，在最近的历史上，在卡斯卡迪亚大型地震发生了大量地震。博士后研究员是一位早期的女性科学家。该研究的结果将在研讨会和会议上介绍，并将为UTIG的高中课程开发计划做出贡献。 Part 2Funds are provided for a postdoctoral fellow to conduct amplitude preserved seismic prestack depth migration, 2D waveform modeling of fault plane reflections, and fluid flow modeling of the 2D multichannel seismic data at Nicaragua, Cascadia, Nankai, and Alaska subduction zones to explore the limits on the water content of the fault zones in the oceanic plate seaward of the trench.从这些结果中，她将开始定量评估不同俯冲带的传入板的水合状态。对底板和哥斯达黎加RICA 3D数据集的下降板的断层模型的地震属性分析，近种子沉积物和基底地壳岩石，以及在上层和下部板的水学系统之间评估流体交换的波形模型。博士后研究员将在向下迁移到上板时沿着板板的断层驱动水。这项研究的结果将有助于回答地理位主义俯冲周期和变形科学计划中的两个关键问题：“挥发物，液体和熔体如何通过俯冲系统存储，转移和释放？”和“从进入板和沟槽到弧和后弧的流动性释放和转移如何影响板界面的流变和动力学？”更广泛的影响：拟议的工作将提供对俯冲Zones中的地球扎华潜力的更好理解，这与Casscadial eargath的大幅度地震量特别相关。该项目将支持早期女性科学家的博士后培训。该研究的结果将在研讨会和会议上介绍，并将为UTIG的高中课程开发计划做出贡献。