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RESEARCH OF DETAILED STRUCTURE BENEATH ICELANDIC PLATEAU BY USE OF OCEAN BOTTOM SEISMOGRAPHS, WITH A COOPERATION BETWEEN JAPAN AND NORWAY

日本和挪威合作利用海底地震仪研究冰岛高原下方的详细结构

基本信息

批准号：
63041008
负责人：
SHIMAMURA Hideki
金额：
$ 6.4万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Overseas Scientific Survey.
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

项目摘要

By using ocean bottom seismograph (OBS) which were developed in our institutes, We made researches of detailed crustal structures of Sognefjord, which is the longest fjord in Norway with a length of 200 km) in 1987, and a very detailed three dimensional structure beneath northeast Atlantic Ocean bottom between Norwegian coast and Mohns Ridge in 1988. Also, we made a detailed study of natural earthquake activities off Norway in 1989.In the controlled source experiments, 20 - 25 OBS were deployed on ocean bottom by research ships of Noway and West Germany. A powerful airgun array was used for the controlled source.In the 1987 experiment, we obtained a detailed structure beneath Sognefjord where we find a good correspondence with a surface geological structure and traced a deeper extension of the boundary.In the 1988 experiment, two successive experiments were carried out, each of which made use of 20 - 25 OBS, Both were the highest density experiment which were made to date. The region off Lofoten is covered by a flow lava which is impossible to penetrate by multichannel reflection study so that only OBS could study the crustal structure beneath the layer. The result has helped to study the opening of the Atlantic Ocean. In the 1989 experiment, detailed seismic activity with very small earthquakes has been studied for the first time in a region between Norwegian coast and Mohns Ridge. The activity had not been able to be observed from the observations on land. The research has helped the study of the intraplate earthquake in the region which had not been well known.

1987年，我们利用研究所研制的海底地震仪（OBS）对挪威最长的峡湾——索内峡湾（全长200公里）进行了详细的地壳结构研究；1988年，我们对挪威海岸与莫恩斯海岭之间的东北大西洋海底进行了非常详细的三维结构研究。此外，我们对1989年挪威近海的自然地震活动进行了详细的研究。在可控源实验中，挪威和西德的科考船在海底布置了20 - 25个OBS。一个强大的气枪阵列被用于控制源。在1987年的实验中，我们获得了Sognefjord下面的详细结构，在那里我们发现了与地表地质结构的良好对应关系，并追踪了边界的更深延伸。在1988年的实验中，连续进行了两次实验，每次使用20 - 25个OBS，都是迄今为止进行的密度最高的实验。罗浮敦附近地区为流动熔岩覆盖，多通道反射研究无法穿透，因此只有OBS才能研究层下地壳结构。这一结果有助于研究大西洋的开放。在1989年的实验中，在挪威海岸和莫恩斯海岭之间的一个地区，首次研究了非常小的地震的详细地震活动。从陆地上的观测无法观察到这种活动。该研究有助于对该地区不为人知的板内地震的研究。