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Ocean Bottom Seismographic Survey of the Earthquake Swarm which occur beneath Mid Atlantic Ridge.

对大西洋中脊下方发生的地震群进行海底地震调查。

基本信息

批准号：
06044005
负责人：
SHIMAMURA Hideki
金额：
$ 11.65万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06044005/
关键词：
Ocean Bottom Seismographic Observations Earthquakes of Mid-Ocean Ridges Ocean Bottom Seismograph Reykjanes Ridge Birth of a (lithospheric) plate Mid-Atlantic Ridge Plate tectonics Passive plate margin 単一パルスエアガン海底微小地震観測

项目摘要

Mid-Atlantic Ridge is the place where plate (lithosphere) is being born.. Because usual land-based seismographs are too far to study Ridges, we made use of 30-50 sensitive portable OBSs (Ocean Bottom Seismographs) to make detailed microearthquake observations and refraction studies to study detailed crustal/upper mantle structures. Also we studied Atlantic passive margins, which is a remnant of spreading of the Atlantic Ocean.We brought about 30 OBSs to the Atlantic in 1994,1995 and 1996. In 1994 we made two experiments in the Atlantic : one on the Reykjanes Ridge and the other in the Bay of Biscay. In the former, we succeeded to obtain a detailed hypocentral distribution of microearthquakes, and the structure beneath the Ridge. In the latter, we succeeded to develop a powerful controlled source survey to study crustal/upper mantle structure, with a combination of the single-bubble pulse airgun and the sensitive OBS.In 1995 we made an extensive OBS-airgun refraction survey in a region … More from Kolbeinsey Ridge, which is a part of Mid-Atlantic Ridge north of Iceland, to Jan Mayn Ridge, which is thought a remnant continent before the Atlantic was born. We have succeeded to obtain a continuous detailed structure for the whole transect from Kolbeinsey Ridge to Jan Mayn Ridge, which is quite important to study the history of opening of the Atlantic Ocean.In 1996 we also made two experiments in the Atlantic : one on the Voring Basin off Norway and the other in the transition from Reykjanes Ridge to Iceland. The former was to illustrate a very detailed crustal structure off Norway, where a remnant initiation of the opening of the Atlantic is kept beneath the flow basalt. The flow basalt is very impenetrable rock for the usual seismic reflection method used in the sea, however our OBS refraction survey can penetrate beneath the layr. The latter was to study micro-earthquakes beneath the transition from Reykjanes Ridge to Iceland which is essential to study how Iceland and the Ridge was formed. We also made controlled source study in this area to elucidate detailed crustal structure of the transition. We used 30 OBS plus 47 temporary land seismographs for this study. Less

大西洋中脊是板块（岩石圈）诞生的地方。由于通常的陆基地震仪距离研究中脊太远，我们利用30-50台灵敏的便携式OBS（海底地震仪）进行详细的微地震观测和折射研究，以研究详细的地壳/上地幔结构。我们还研究了大西洋被动边缘，这是大西洋扩张的残余物。我们于1994年、1995年和1996年将大约30个OBS带到大西洋。1994年，我们在大西洋进行了两次实验：一个在雷克雅内斯海脊，另一个在比斯开湾。在前者中，我们成功地获得了微地震的详细震源分布以及山脊下方的结构。在后者中，我们成功地开发了一种强大的受控源调查，以研究地壳/上地幔结构，结合了单泡脉冲气枪和敏感的 OBS。1995 年，我们在一个地区进行了广泛的 OBS 气枪折射调查……更多，从科尔宾塞海脊（冰岛北部大西洋中脊的一部分）到扬马恩海脊（被认为是大西洋之前的残余大陆）诞生了。我们成功地获得了从科尔本塞海岭到扬马恩海岭的整个断面的连续详细结构，这对于研究大西洋的开放历史非常重要。 1996年我们还在大西洋进行了两次实验：一次在挪威附近的沃林盆地，另一次在雷克雅内斯海岭到冰岛的过渡段。前者旨在展示挪威附近非常详细的地壳结构，其中大西洋开口的残余起始部分保留在流动玄武岩下方。对于海洋中常用的地震反射方法来说，流动玄武岩是非常难以穿透的岩石，但我们的 OBS 折射勘测可以穿透该层以下。后者是研究从雷克雅内斯山脊到冰岛过渡区下方的微地震，这对于研究冰岛和山脊的形成方式至关重要。我们还对该地区进行了受控源研究，以阐明转变的详细地壳结构。我们在这项研究中使用了 30 个 OBS 和 47 个临时陆地地震仪。较少的

项目成果

期刊论文数量（53）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

望月將志,小平秀一,塩原肇,島村英紀,Bryndis Brandsdottir,Erik Sturkell,Ragnar Stefansson: "海底地震観測によるTjornes Fracture Zoneの地震活動" 『地震』,第2輯. 48. 257-270 (1995)

Masashi Mochizuki、Shuichi Kodaira、Hajime Shiobara、Hideki Shimamura、Bryndis Brandsdottir、Erik Sturkell、Ragnar Stefansson：“基于海底地震观测的 Tjornes 断裂带地震活动”，地震，卷 2. 48. 257-270 (1995)