EAGER: Bubble Plume Emissions from Fault Zones within the Puget Sound Forearc

EAGER：普吉特湾前弧内断层带的气泡羽流排放

• 批准号: 1945975
• 负责人: Harlan Johnson
• 金额: $ 9.4万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1945975&HistoricalAwards=false
• 关键词: EAGER; Bubble; Plume; Emissions; Fault

This EAGER proposal will obtain samples from newly identified gas and fluid plumes in Puget Sound to determine whether the plumes come from the Cascadia subduction zone megathrust. The idea is that deep regional faults act as pathways for upward migration of fluid that has been generated by heating along the plate interface between the North America and the incoming Juan de Fuca Plate. If the Puget Sound plumes have a subduction zone source, the plumes may provide a means to monitor the pressure and chemistry of the fluid between the plates, and provide a new approach for studying slip on the Cascadia subduction zone megathrust fault. This project is a first step toward developing predictive models for understanding seismic hazards in the heavily-populated Pacific Northwest.Upward migration of fluid and gas through the forearc crust that overlies active subduction zone faults has been observed in settings very similar to the Puget Sound region, including Japan Trench on the Kii peninsula, New Zealand at the Hikurangi margin, and on the Baja California Peninsula, Mexico. Although these fluid seeps emit fluid with helium, oxygen, hydrogen isotope signatures that unambiguously identify them as coming from the subduction zone fault, none of them emit fluid and gas with the vigor or wide spatial distribution observed within Puget Sound. Critically, none of the previous globally-identified forearc plumes are in subduction zones where periodic Episodic Tremor and Slip (ETS) events occur - that arise from periodic local slippage on the subduction zone fault. At Cascadia, these ETS events have a quasi-period of 14 months and variations in the amplitude and intervals are newly-recognized as potential precursors to both regional faulting and large episodic megathrust earthquakes. If the the new Puget plumes are found to be derived from the subduction zone megathrust zone, it would be the first step in using correlations between the variations in emissions and ETS behavior to understand slip on the megathrust.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.

该急切的建议将从普吉特声音中新鉴定的气体和流体羽流中获取样品，以确定羽毛是否来自卡斯卡迪亚俯冲带Megathrust。这个想法是，深区断层是通过沿着北美和即将到来的胡安·德福卡板（Juan de Fuca Plate）在板块界面加热而产生的流体向上迁移的途径。如果普吉特声音羽流具有俯冲带源，则羽可能可以提供一种监测板之间流体压力和化学性质的方法，并为研究Cascadia俯冲带Megathrust断层的滑动提供了新的方法。 This project is a first step toward developing predictive models for understanding seismic hazards in the heavily-populated Pacific Northwest.Upward migration of fluid and gas through the forearc crust that overlies active subduction zone faults has been observed in settings very similar to the Puget Sound region, including Japan Trench on the Kii peninsula, New Zealand at the Hikurangi margin, and on the Baja California Peninsula, 墨西哥。尽管这些液体渗入用氦气，氧，氢同位素特征散发出液体，这些液体明确地识别出它们来自俯冲带的断层，但没有一个在Puget Sound中观察到的活力或空间分布。至关重要的是，以前的全球识别前李子都没有在俯冲带中，在俯冲区域中，周期性的震颤和滑动事件（ETS）事件发生 - 这是由俯冲区断层上的周期性局部滑动引起的。在Cascadia，这些ETS事件的准周期为14个月，幅度和间隔的变化新近被认为是区域断层和大型情节性巨型地震的潜在前体。如果发现新的普吉特羽流是源自俯冲带的巨型区域，那么这将是使用排放和ETS行为的变化之间相关性的第一步，以理解在巨型上的斜线。本奖项奖反映了NSF的法定任务，并通过使用基金会的智力效果和广泛的影响来评估支持，并被视为值得的支持。