Collaborative Research: Slow-Slip and Fluid Flow Response Offshore New Zealand -Probing The Nature Of The Margin Hydrogeochemical System

合作研究：新西兰近海慢滑移和流体流动响应 - 探索边缘水文地球化学系统的性质

• 批准号: 1753665
• 负责人: Marta Torres
• 金额: $ 49.72万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1753665&HistoricalAwards=false
• 关键词: Collaborative; Research; Slow; Slip; Fluid; Collaborative; Research; Slow; Slip; Fluid

Observations at subduction zones over the past two decades have revealed a range of modes by which stress is released on the plate boundary, including periodic slow slip behavior. Slow slip events occur at a rate intermediate between long-term tectonic plate motion and the fast slip velocity that occurs during earthquakes. Thus, slow slip is thought to span the transition between stable slip and the stick-slip process that generates earthquakes. An important mechanism that could cause the transitions in slip style is the evolution of pressure along the fault that is generated by the accumulation and release of fluids. There is a concerted and extensive international sampling and monitoring effort to understand slow slip at the Hikurangi margin offshore New Zealand. A missing piece in this effort is the sampling and monitoring of fluids along seafloor fault zones over a long enough period of time to capture a slip event. This project will address this problem and will provide a two-year continuous record of fluid flow rate and composition over the time frame of the next expected large slow slip event. The project will add value to other ongoing NSF-funded programs at this margin such as scientific ocean drilling and seismic surveys aimed at understanding slow slip events. From both the scientific and societal perspectives, results from this project will contribute to our understanding of earthquake activity not only offshore New Zealand but worldwide. This project has a large component of international collaboration. The project supports the training of graduate and undergraduate students. This project addresses the GeoPRISMS Program's Subduction Cycles and Deformation Initiative Science Plan by testing interrelationships between fluid production, fluid flow, and slow slip at the Hikurangi margin off New Zealand. At the Hikurangi margin, the recognition of dramatic changes in the along-strike depth distributions of slow-slip events (SSEs) and their recurrence intervals, interseismic coupling, inferred pore pressure, and other subduction-related parameters have resulted in a concerted international effort to acquire seismological, geodetic, other geophysical, and geomechanical data. This project will complement and extend these efforts by providing 1) a two-year continuous record of fluid flow rate and composition over the timeframe of the next expected large SSE; 2) information on the present background state of fluid flow and how it relates to inferred overpressure along the plate boundary; and 3) comparative geochemical and hydrologic data between the northern and southern sections of the margin. The work plan combines ship operations and Remotely Operated Vehicle (ROV) surveys in a nested approach to constrain the margin-wide fluid flow distribution. Coring, heat flow measurements, and benthic fluid flow meter deployments will target fault zones and off-fault locations from the deformation front to the shelf-break. Continuous fluid flow rate measurements at off-fault locations will quantify the fluid flow response to local volumetric strain during slip, and comparative data at fault zones will provide information on the hydrologic responses to slip.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.

在过去的二十年中，俯冲带的观察结果揭示了一系列模式，通过这些模式在板边界上释放应力，包括周期性的慢滑行行为。慢滑动事件以中间的速率发生在长期的构造板运动和地震期间发生的快速滑移速度之间。因此，慢速滑移被认为跨越了稳定滑动与产生地震的粘性滑移过程之间的过渡。可能导致滑动方式过渡的重要机制是压力沿着液体的积累和释放产生的断层的演变。在新西兰海洋远处的海岸边距慢速滑倒中，有一致且广泛的国际抽样和监控工作。这项工作中缺少的作品是在足够长的时间内对沿着海底断层区域的流体进行采样和监测以捕获滑动事件。该项目将解决此问题，并将在下一个预期的大型慢速事件的时间范围内提供两年的流体流量和组成记录。该项目将在此空间中为其他正在进行的NSF资助的计划增加价值，例如科学的海洋钻井和旨在了解慢速滑移事件的地震调查。从科学和社会的角度来看，该项目的结果将有助于我们对地震活动的理解，不仅是新西兰近海，而且在全球范围内。该项目具有国际合作的很大一部分。该项目支持培训研究生和本科生。该项目通过测试新西兰的Hikurangi Margin的流体产生，流体流量和缓慢滑移之间的相互关系来解决Geoprisms计划的俯冲周期和变形倡议计划。在高曲司朗的边缘，慢速事件（SSE）及其复发间隔及其及其复发间隔的巨大变化的认识及其互联耦合，推断孔隙压力以及其他相关参数导致了一致的国际努力，从而获得了地震，地理学，地理学，其他地球学，GEOM机制，以及GEOM机制，GEOM和GEOM机制。该项目将通过提供1）在下一个预期的大型SSE的时间表上的流体流量和组成的两年连续记录来补充和扩展这些努力； 2）有关流体流的当前背景状态及其与沿板边界推断过压的信息； 3）边缘北部和南部部分之间的比较地球化学和水文数据。该工作计划结合了船舶操作和远程操作的车辆（ROV）调查，以嵌套的方法约束范围范围的流体流量分布。加油，热流量测量和底栖流体流量计的部署将瞄准断层区域和越野车位置，从变形正面到架子断裂。在不良位置处的连续流体流量测量结果将量化对滑移期间对局部体积应变的流体流动响应，并且故障区域的比较数据将提供有关滑道的水文响应的信息。该奖项反映了NSF的法定任务，并认为使用该基金会的知识分子优点和广泛的影响来审查CRITERIA，并被认为是值得通过评估的支持。