Development of Ocean Bottom Electromagnetic Measurement System and Three-dimensional Structure of the Transition Zone between the Ocan and the Continent

海底电磁测量系统研制及海洋与大陆过渡带三维结构

基本信息

批准号：
62840009
负责人：
HAMANO Yozo
金额：
$ 11.65万
依托单位：
Earthquake Research Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

Purpose of the present investigation is to develope an ocean bottom system which measures the variations of the three components of the magnetic field and two horizontal components of the electric field of the earth. Such a system is required to study the complicated electromagnetic structures beneath the Japanese Islands and the adjacent area. During the studying period of 1987 and 1988, the system named Obem (Ocean Bottom Electric and Magnetic field measurement apparatus) has been completed, and tested at Kakioka Magnetic Observatory of the Meteololgical Agency and Yatsugatake Magnetic Observatory of the University of Tokyo. Druing the development of the apparatus, magnetic sensor, electrode, pressure vessel, measureing circuits, power source, and acoustic release system have been reexamined to fit to the present purpose.The first sea floor measurement by using the presently developed Obem was made during june and November of 1988 at the southern-most part of the Juan de Fuca ridge. The project is a part of the international coopertive study (EMRIDGE project), which aimes to investigate the generating process of the oceanic plate from a detailed study of the electromagnetic structure beneath the ridge system. The present apparatus is suitable for the study, since one instrument can measure a complete set of the electromagnetic signals at the site. The sea floor apparatus including the present one was installed by hakuho-maru which belongs to the Ocean Research institute of the University of Tokyo, and were safely recovered by Canadian research vessel Parizeau.

本研究的目的是开发一个海底系统，测量地球磁场的三个分量和电场的两个水平分量的变化。研究日本列岛及邻近地区下方复杂的电磁结构需要这样的系统。 1987年和1988年的研究期间，完成了名为Obem（海底电场和磁场测量装置）的系统，并在气象厅柿冈磁力观测站和东京大学八岳磁力观测站进行了测试。在该设备的开发过程中，对磁传感器、电极、压力容器、测量电路、电源和声学释放系统进行了重新审查，以适应当前的目的。使用目前开发的 Obem 进行了第一次海底测量。 1988年11月在胡安德富卡山脊的最南端。该项目是国际合作研究（EMRIDGE项目）的一部分，旨在通过详细研究洋脊系统下方的电磁结构来研究海洋板块的生成过程。本装置适合这项研究，因为一台仪器可以在现场测量一整套电磁信号。包括本装置在内的海底装置是由东京大学海洋研究所所属的白凤丸安装的，并由加拿大科考船Parizeau安全回收。