Construction and Deployment of a Seafloor Drift-Corrected Pressure Gauge for Deformation Observation at Axial Volcano

“这项奖励是根据2009年美国复苏和再投资法案（公法111-5）资助的。”大地测量学在了解塑造地球的构造方面起着重要作用。地壳。地面大地测量学是一门成熟、先进的科学。另一方面，受海水对电磁辐射不透明的限制，海底大地测量学相对较新，仍然需要替代技术来可靠地探测海底变形。用声学方法观察海底的水平变形已经取得了成功，但深海声速结构阻碍了该技术在垂直维度上的应用。幸运的是，海水压力测量提供了一种以厘米精度观察垂直位置变化的方法。然而，一个关键因素限制了从海水压力变化推断垂直变形的能力：压力表一直存在且不可预测的漂移。π吗?我们设计并测试了一个活塞计压力基准（PGPR）的实验室原型。该原型具有可重复性，相当于在模拟海洋中脊的代表深度处产生0.5厘米的垂直变形。π吗?美国要求资助在海底建造和部署这样一种仪器，以提供一种消除大地压力表漂移的方法，并允许观察海底高度的长期变化。更广泛的影响水下大地测量新技术的发展是进一步了解数万公里水下板块边界过程的必要步骤；它还将有助于监测边缘地区早期的山体滑坡。因此，这是评估沿海地区自然灾害的一个重要研究领域。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Geodesy plays an important role in gaining understanding of the tectonics that shape Earth?s crust. Subaerial geodesy is a mature, advanced science. Submarine geodesy, on the other hand, limited by the opacity of seawater to electromagnetic radiation, is relatively new and is still in need of alternate techniques to detect seafloor deformation reliably. Acoustic methods to observe horizontal deformations of the seafloor have been successful, but the deep ocean sound velocity structure prohibits the technique from being useful in the vertical dimension. Fortunately, seawater pressure measurements provide a method to observe changes in vertical position with centimeter precision. A key factor, however, limits the ability to infer vertical deformation from seawater pressure change: the ever present and unpredictable drift in pressure gauges. The PI?s have designed and tested a laboratory prototype for a piston gauge pressure reference (PGPR). The prototype has a demonstrated repeatability equivalent to 0.5 cm of vertical deformation at a simulated depth representative of a mid-ocean ridge. The PI?s request funding to construct and deploy such an instrument on the seafloor to provide a means to remove drift from geodetic pressure gauges and allow observation of secular variation in seafloor height.Broader Impacts Development of new technologies for underwater geodesy is a needed step to further our understanding of processes along the several 10,000's km of submerged plate boundaries; it would also help with monitoring incipient landslides along the margins. It is therefore a critical field of research for the assessment of natural hazards in coastal areas.