Plate Dynamics at the Eastern Margin of the Japan Sea from Long-term Seafloors Observation.

来自长期海底观测的日本海东缘板块动力学。

基本信息

批准号：
63420055
负责人：
SUYEHIRO Kiyoshi
金额：
$ 1.98万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63420055/
关键词：
Downhole seismometer Brood-band seismometer Ocean Drilling Program Japan Sea 海底孔円地震計

项目摘要

The Japan Sea constitutes a back arc in the northern Japan plate subduction zone. How the subducting Pacific plate interacts with the overriding plate and the surrounding upper mantle is still not fully understood. This is partly due to the lack of key observational data from the surrounding deep seafloors. We have developed and emplaced a digital broadband seismometer in an ODP hole about 160 km west off NE Japan from the D/V JOIDES Resolution in Sep., 1989, in order to initiate a long-term seismic observation.Hole 794D is 733.5 m deep below seafloor (water depth: 2818 m). The borehole package including a 3-component feed-back type accelerometer and a digital data telemetry system was clamped near the bottom within solid basalt. The sensor is a ruggedized version of Guralp CMG-3 with leveling mechanisms for horizontal sensors. The seismic data are sent uphole in two gains at a rate of 80 Hz/ch, 16-bit each via the 7-conductor logging cable. A controlled source seismic experiment was carried out on R/V Tansei-maru for two days while recording the borehole data on the drill ship real-time. Then, the seafloor long-term seismic recording system including a battery package (24V-38AH x 20) and glass sphere buoys with an acoustic transponder attached to the end of a 6000 m rope was deployed from another vessel. The system can record 60 MB of data by time window/event trigger algorithms. Thus we believe we have initiated a broadband long-term seismic observation for the first time in a marine environment.

日本海构成日本北部板块俯冲带的后弧。俯冲的太平洋板块如何与上覆板块和周围的上地幔相互作用仍不完全清楚。部分原因是缺乏周围深海底的关键观测数据。根据1989年9月的D/V JOIDES决议，我们在日本东北部以西约160公里处的ODP孔中开发并安装了数字宽带地震仪，以开始长期地震观测。794D孔深733.5 m海底以下（水深：2818 m）。包括三分量反馈型加速度计和数字数据遥测系统的钻孔套件被夹紧在固体玄武岩内的底部附近。该传感器是 Guralp CMG-3 的加固版本，具有用于水平传感器的调平机构。地震数据通过 7 芯测井电缆以两个增益以 80 Hz/ch、每个 16 位的速率发送到井上。在R/V Tansei-maru上进行了为期两天的受控源地震实验，同时在钻探船上实时记录钻孔数据。然后，从另一艘船上部署了海底长期地震记录系统，包括电池组（24V-38AH x 20）和玻璃球浮标，玻璃球浮标带有连接到 6000 米绳索末端的声学应答器。系统可以通过时间窗口/事件触发算法记录60MB的数据。因此，我们相信我们首次在海洋环境中启动了宽带长期地震观测。