Collaborative Research: Near-Trench Community Geodetic Experiment

合作研究：近海沟群落大地测量实验

• 批准号: 2232641
• 负责人: Donna Charlevoix
• 金额: $ 40.26万
• 依托单位: Incorporated Research Institutions for Seismology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2027-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2232641&HistoricalAwards=false
• 关键词: Collaborative; Research; Near; Trench; Community

Collaborative Research: Near-Trench Community Geodetic ExperimentThe largest earthquakes (and the resulting tsunamis) occur offshore, but the instruments traditionally used to study the ground deformation associated with these events can only be used on land. Therefore, traditional surveying cannot quantify the offshore seismic hazards. Studying these hazards requires tools designed to collect data offshore. One such tool is the GNSS-Acoustic method, an offshore GPS (Global Positioning System) method with sets of instruments set up on the seafloor in circular groupings. These instruments are positioned relative to a remote-controlled sea surface robot using sound pulses. This ‘Wave Glider’ can use GPS to determine its position, allowing the seafloor instruments to be located with cm-level accuracy. Tracking these positions over time allows researchers to learn how the deforming seafloor builds up stress that ultimately results in earthquakes. This project follows recommendations by a large group of scientists who are interested in knowing how seafloor deforms in subduction zones as the seafloor crust gradually slides beneath the continental crust. The project aims to detect the motions of the seafloor at six stations in the offshore Cascadia region and six in the offshore Alaska region. This will aid the scientific community in assessing the seismic and tsunami hazards in these regions. The data will all be open access and the project will contribute to training the next generation of geodetic scientists.The 2011 Tohoku earthquake demonstrated that coseismic rupture can extend to shallow depths along a subduction megathrust, where large vertical displacements of the seafloor can generate damaging tsunamis. This project will clarify whether a similar event can happen in the offshore Cascadia and Alaska regions by using seafloor geodetic observations to infer the level of elastic strain stored in the accretionary prisms of Cascadia and Alaska subduction zones. The researchers will deploy GNSS-Acoustic instruments from the seafloor geodesy community pool, which consists of 51 GNSS-Acoustic transponders (enough for 17 new GNSS-Acoustic sites) and 3 Wave Gliders, following recommendations from 165 scientists and students who attended a seafloor geodesy community workshop on how best to make use of the instrument pool. Twelve new GNSS-Acoustic sites will be established during this experiment, with six along each of the Cascadia and Alaska subduction zone trenches, which were identified by workshop attendees as high-value science targets. The researchers will survey these new sites as well as the seven sites already established in these regions annually throughout the five years of the project. These positions will be used to infer interseismic velocities from which the rate of elastic strain buildup in the accretionary prisms can be determined, with implications for the earthquake and tsunami hazard in Alaska and the Pacific Northwest. The data will all be open access and the project will contribute to training the next generation of geodetic scientists.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.

协作研究：近沟社区的大地测量实验最大的地震（以及由此产生的海啸）发生在海上，但是传统上用于研究与这些事件相关的地面变形的工具只能在陆地上使用。因此，传统的测量无法量化近海地震危害。研究这些危害需要旨在收集近海数据的工具。一种这样的工具是GNSS-Acoustic方法，一种近海GPS（全球定位系统）方法，其中包含在圆形分组中在海底设置的仪器集。这些仪器使用声音脉冲相对于遥控的海面机器人定位。这种“波滑翔机”可以使用GPS确定其位置，从而使海底仪器以CM级的精度位于位置。随着时间的流逝，跟踪这些位置使研究人员能够学习变形的海底如何产生最终导致地震的压力。该项目遵循了一大批科学家的建议，他们有兴趣知道海底如何在俯冲带中变形，因为海底地壳逐渐在连续的地壳下逐渐滑动。该项目旨在检测卡斯卡迪亚海上六个站点的海底运动和阿拉斯加近海地区的六个。这将有助于科学界评估这些地区的地震和海啸危害。数据将全部是公开通道，该项目将有助于训练下一代的大地测量科学家。2011年的Tohoku地震表明，沿俯冲的巨型巨星，coseissic破裂可以延伸至浅层深度，在那里，海底的大型垂直垂直位移可以产生破坏性的Tsunamis。该项目将通过使用海底大地测量观测来推断Cascadia和阿拉斯加俯冲Zones的增生棱镜中储存的弹性菌株水平，从而在海上卡斯卡迪亚和阿拉斯加地区发生类似事件。 The researchers will deploy GNSS-Acoustic instruments from the seafloor geodesy community pool, which consists of 51 GNSS-Acoustic transponders (with enough for 17 new GNSS-Acoustic sites) and 3 Wave Gliders, following recommendations from 165 scientists and students who attended a seafloor geodesy community workshop on how best to make use of the instrument pool.在本实验期间，将建立十二个新的GNSS声学站点，每个Cascadia和阿拉斯加俯冲带沟渠中有六个，这是由研讨会参与者确定为高价值科学目标的。研究人员将在项目的五年中调查这些新站点以及每年在这些地区已经建立的七个站点。这些位置将用于推断可确定增生棱镜中弹性应变率的速度，这对阿拉斯加和太平洋西北地区的地震和海啸危害产生了影响。数据将全部是公开访问，该项目将有助于培训下一代的大地学科学家。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，认为通过评估被认为是珍贵的支持。