Advances in Seafloor Geodesy: Expanded Applications of Wave and Solar Powered Surface Vehicles

俯冲带是始于近海的地质断层，在那里一个构造板块滑到另一个板块之下。由于沿着断层的摩擦，一些下行的板块运动被缓慢地转移到上部板块，后者弯曲收缩，储存了运动。偶尔，这种积聚的运动会以地震的形式迅速释放，并移位海底，引发海啸。加利福尼亚州、俄勒冈州和华盛顿州北部近海的卡斯卡迪亚俯冲带，以及阿拉斯加近海的阿留申俯冲带，过去曾引发过大地震和海啸，现在还会这样做。测量这种缓慢堆积发生的地点和速度可以提高对潜在危险的理解。这需要近海海底传感器收集数据，而在过去，船只需要访问这些数据。在这个项目中，将开发和测试新的方法，使用更少的仪器和遥控的自给动力海面飞行器，而不是船只，以降低数据收集的成本。这是一个为期一年的项目，目的是实现从海底到波浪和太阳能动力海面飞行器的声学上传，并测试一种使用单一海底应答器在浅水(200米)收集GPS-声学数据的新的低成本方法。将对机载计算机进行编程，以控制声学测距系统在调制解调器模式下运行。一个嵌入应答器的压力传感器将部署在海上SIO，以测试不同距离和深度的上传能力。此外，将在SIO近海部署一个应答器，海面飞行器将远程操作，绕应答器最多两周，收集GPS-声波数据。然后，我们将评估在浅水中定位的重复性是否可与现有的GPS-声波方法相媲美，在现有方法中，数据是从由三个或更多应答器组成的阵列的中心收集的。

Subduction Zones are geologic faults that begin offshore where one tectonic plate slides beneath another. Due to friction along the fault some of the down-going plate motion is slowly transferred to the upper plate which bends and contracts storing the motion. Occasionally, this built-up motion is rapidly released as an earthquake and displaces the sea floor causing a tsunami. The Cascadia subduction zone offshore northern California, Oregon and Washington and the Aleutian subduction zone offshore Alaska have generated large earthquakes and tsunami in the past and will do so again. Measuring where and how fast this slow build-up occurs can improve understanding of the potential hazard. This requires offshore seafloor sensors to collect data, and in the past, ships to access this data. In this project, new methods will be develop and tested that use fewer instruments and remotely-piloted, self-powered sea surface vehicles, rather than ships, to lower the cost of data collection.This is a one-year project to implement acoustic upload of data from the sea floor to a wave- and solar-powered sea surface vehicle, and test a new lower cost method of collecting GPS-Acoustic data in shallow water ( 200 m) using a single seafloor transponder. An onboard computer will be programed to control the acoustic ranging system to operate in modem mode. A pressure sensor embedded with a transponder will be deployed offshore SIO to test the upload capability at varying ranges and depths. In addition, a transponder will be deployed offshore SIO and the sea surface vehicle will be operated remotely to circle the transponder for up to two weeks collecting GPS-Acoustic data. We will then evaluate if repeatability of positioning in shallow water is comparable to the existing GPS-Acoustic approach where data are collected from the center of an array comprised of three or more transponders.