Collaborative Research: Meshed GNSS-Acoustic Array Design for Lower-Cost Dense Observation Fields

合作研究：用于低成本密集观测场的网状 GNSS 声学阵列设计

• 批准号: 2321297
• 负责人: Andrew Newman
• 金额: $ 49.01万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2321297&HistoricalAwards=false
• 关键词: Collaborative; Research; Meshed; GNSS; Acoustic

Precise observations of seafloor deformation is important for assessing ongoing geologic processes and the hazards they pose, including the largest earthquakes, tsunamis, submarine volcanism, hydrocarbon changes, and submarine landslides. Making observations of the centimeter-scale deformation that occurs over a year or longer using a combination of sea surface and seafloor instrumentation is currently expensive, particularly when using a large research vessel as a part of the measurement design. In this project, the team will use a rather new but previously tested autonomous, green-powered vessel that replaces the ship-based measurement design, reducing measurement costs by more than an order of magnitude over prior methods. To further reduce instrumentation costs and enable more broad use, the project will test new design geometries that have the potential to significantly increase capabilities where dense observations are needed. During this project, a postdoctoral scholar will be trained as a next-generation scientist and educator. The data collected will be contributed to a community data archive, and methods will be incorporated into community software for research. Following the project, the instrumentation will become a part of an existing NSF-funded instrument pool, doubling the capabilities for deep-water observations from 3000 to 6000 meters. The surface vessel for these operations, a commercially available Wave Glider, will be outfitted with antennas for positioning itself using Global Navigational Satellite Systems (GNSS). The vessel will interrogate a mesh-network of seafloor transponders during the summers of 2024 and 2025 using a lower frequency acoustic signal than currently available with the US instrument pool to allow for the extended ranging needed for deeper water operation. The 10-transponder array will be deployed between 4 and 6 km depth along a segment of the Aleutian trench in 2024, combining ship-activities with an existing community geodetic experiment, that can only extend to 3 km depth. The dense mesh-network design with the shared use of transponders could potentially allow for a ten-fold increase in instrumental efficiency, depending on geometry, over existing methods existing methods that require three transponders per observation point. Lastly, the experiment will additionally evaluate the potentially increased errors associated with necessarily high-gradient seafloor environments that are common in subduction zones. Such steep measurements could be similarly applied to passive continental slopes that have the potential for destructive submarine landslides. While the design experiment tests methodology, the location was chosen because little is known about the behavior of faults in the region, where a large earthquake in 1946 created an outsized tsunami. Detailed information about ongoing fault behavior in the region can illuminate the currently unknown mechanical coupling in the region that builds for future earthquakes.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.

海底变形的精确观测对于评估正在进行的地质过程及其造成的危害非常重要，包括最大的地震、海啸、海底火山活动、碳氢化合物变化和海底滑坡。 目前，使用海面和海底仪器组合来观测一年或更长时间发生的厘米级变形的成本很高，特别是在使用大型研究船作为测量设计的一部分时。 在这个项目中，该团队将使用一种相当新的但之前经过测试的自主绿色动力船舶来取代基于船的测量设计，与以前的方法相比，将测量成本降低一个数量级以上。 为了进一步降低仪器成本并实现更广泛的使用，该项目将测试新的设计几何形状，这些几何形状有可能显着提高需要密集观测的能力。在这个项目中，一名博士后学者将被培训为下一代科学家和教育家。 收集的数据将贡献给社区数据档案，方法将纳入社区软件中进行研究。 该项目完成后，该仪器将成为 NSF 资助的现有仪器池的一部分，将深水观测能力从 3000 米增加一倍至 6000 米。用于这些操作的水面舰艇是商用波浪滑翔机，将配备天线，用于使用全球导航卫星系统（GNSS）进行自身定位。 该船将在 2024 年和 2025 年夏季使用比美国仪器池目前可用的频率更低的声波信号询问海底转发器网状网络，以实现更深水作业所需的扩展范围。这个由 10 个应答器组成的阵列将于 2024 年沿着阿留申海沟的一段部署在 4 至 6 公里深度之间，将船舶活动与现有的社区大地测量实验相结合，该实验只能延伸到 3 公里深度。与每个观测点需要三个转发器的现有方法相比，共享转发器的密集网状网络设计可能会使仪器效率提高十倍，具体取决于几何结构。 最后，该实验还将评估与俯冲带常见的必然高梯度海底环境相关的潜在增加的误差。 这种陡峭的测量同样适用于有可能造成破坏性海底滑坡的被动大陆坡。虽然设计实验测试了方法，但之所以选择这个地点，是因为对该地区断层的行为知之甚少，1946 年的一场大地震引发了特大海啸。有关该地区持续断层行为的详细信息可以阐明该地区目前未知的机械耦合，为未来的地震奠定基础。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。