Collaborative Research: Broadband Seismic Measurements on the Deep Ocean Floor: A Pilot Experiment

9523658山本来自伍兹霍尔海洋研究所(马萨诸塞州)、斯克里普斯海洋研究所(加州大学圣地亚哥分校)和罗森斯蒂尔海洋与大气科学学院(佛罗里达大学迈阿密分校)的研究小组将联合开发和测试三种类型的深海地震仪，作为一套海洋传感器的试点实验，以扩大现有的陆基“全球”地震网络，使之成为一个真正覆盖全球的网络。利用宽带地震仪覆盖全球地震，能够以目前尚不可能的分辨率准确确定地球内部结构，并有能力显著改善海啸预警。本项目使用的仪器都是“宽带”传感器，将分别部署在1)海底，2)略埋在海洋沉积物中，3)在现有的海底钻孔内。所有部署工作都将在1997年初进行，为期3个月。钻孔部署将使用专门开发的系统(斯克里普斯研究所)将仪器放置在钻孔中；埋在地下的传感器将与迈阿密大学开发的系统一起部署。测试将在夏威夷附近进行，所有三个系统的结果都将与瓦胡岛上的永久陆地地震仪以及彼此进行比较。该项目由美国国家科学基金会地球科学局海洋科学和地球科学部门联合支持，遵循早期组件仪器的开发和测试计划。预计这项测试将使人们能够决定哪种类型的部署(地面部署、地下部署或钻孔部署)对未来的“海洋地震网络”部署是最佳的。***

9523658 Yamamoto This team of investigators from Woods Hole Oceanographic Institution (Massachusetts), Scripps Institution of Oceanography (University of California, San Diego, California) and Rosenstiel School of Marine and Atmospheric Sciences (University of Miami, Florida) will jointly develop and test three types of deep-ocean seismometers as a pilot experiment for a set of ocean sensors to expand the existing land-based "global" seismic network to one which has truly global coverage. Global seismic coverage with broadband seismometers provides a capability to accurately define the interior structure of the earth with resolution presently not possible, and it provides a capability to significantly improve warnings for tsunamis. The instruments to be used in the present project are all "broadband" sensors, and will be deployed respectively 1) lying on the seafloor, 2) buried slightly within marine sediments, and 3) within an existing seafloor drill hole. All deployments will be carried out for the same 3-month period in early 1997. The borehole deployment will use a specially developed system (Scripps Institution) to place the instrument in the borehole; the buried sensors will be emplaced with a system developed at University of Miami. Tests will take place near Hawaii, and results of all three systems will be compared with a permanent land seismometer on the island of Oahu as well as with each other. This project is jointly supported by Ocean Sciences and Earth Sciences Divisions of the Geosciences Directorate at NSF, and follows earlier development and testing programs of component instruments. It is expected that this test will allow decisions to be made about what types of deployments (surface, buried or in drillholes) will be optimum for future "ocean seismic network" deployments. ***