A Moored Geodetic Seafloor Monitoring System (GEOCE)

国际海洋研究所提议建造和展示一种新的能力，从海洋系泊和观测站进行海底大地运动测量。系泊大地测量海底监测系统将整合几种方法和技术，其中大多数已经在不同的应用中分别得到证明。它由系泊浮标上连续的原始波形差分GPS测量组成，以亚厘米精度确定浮标的水平和垂直运动。海底的水平运动是通过相对于水面浮标的声学应答器询问来测量的，这是现有船基方法的一种变体。在去除海面高度运动(使用GPS)和内部海洋密度波动(使用系泊中的水柱CTD传感器)之后，通过高精度的海底压力测量来确定海底垂直运动。剩余海底压力信号是海底运动或传感器漂移。将增加一个现场校准系统来确定漂移。即使没有这个校准系统，也可以检测到不规则的垂直运动或突发事件。目前的建议包括工程开发，以将这些结合到一个新的(停泊的)配置中，并利用各学科之间的协同作用。更广泛的影响这项活动将通过实现对海洋下板块运动的第一次真正的多尺度时态研究来推进发现。具体地说，它应该有助于理解汇聚边缘的应力和应变过程，而汇聚边缘是大地震和海啸的主要风险区域。最终，它们可能被用来识别面临灾难性事件风险的锁定利润率。拟议的仪器将满足对海底大地测量系统的需求，该系统可提供多时间尺度上垂直和水平形变的GPS参考亚厘米分辨率。GEOCE系统通过为构造/海底运动、水柱和海底压力数据、灾害和气候研究提供信息，有可能对地球物理界和海洋界产生重大影响。这项提议还将有4名研究生参与，培训下一代海洋大地测量员。

The PI's propose to construct and demonstrate a novel capability to carry out geodetic seafloor motion measurements from oceanographic moorings and observatories. The Moored Geodetic Seafloor Monitoring System (GEOCE) system would integrate several methods and technologies, most of which have been proven separately in different applications already. It consists of continuous raw-waveform differential GPS measurements on the surface buoy of the mooring, to determine the horizontal and vertical motion of the buoy with sub-centimeter accuracy. Horizontal seafloor motion is measured via acoustic transponder interrogations relative to the surface buoy, a variant of an existing ship based approach. Vertical seafloor motion is determined via high-precision bottom pressure measurements, after removing sea surface height motion (using the GPS) and internal ocean density fluctuations (using water column CTD sensors in the mooring). The residual bottom pressure signal is seafloor motion or sensor drift. An in-situ calibration system will be added to determine the drift. Irregular vertical motion or sudden events would be detectable even without this calibration system. The current proposal consists of the engineering development to bring these together in a new (moored) configuration, and to exploit the synergy between the disciplines. Broader ImpactsThis activity will advance discovery by enabling the first true multi-scale temporal studies of plate motions beneath the oceans. Specifically, it should help to understand the processes of stress and strain at convergent margins, which are a major risk area for great earthquakes and tsunamis. Eventually, they could be used to identify locked margins at risk of catastrophic events. The proposed instrumentation will fill the need for a seafloor geodetic system that provides GPS referenced, sub-centimeter resolution of vertical and horizontal deformation over multi-time scales. The GEOCE system has the potential to significantly impact both the geophysical and oceanographic communities by providing information for tectonic/sea floor motion, water column and bottom pressure data, hazard, and climatic studies. This proposal will also involve the participation of 4 graduate students, training the next generation of marine geodesists.