Collaborative Research: Seismicity of the Equatorial Mid-Atlantic Ridge and its Large Offset Transforms

合作研究：赤道大西洋中脊的地震活动及其大偏移量变换

• 批准号: 1062238
• 负责人: Robert Dziak
• 金额: $ 39.12万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2017-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1062238&HistoricalAwards=false
• 关键词: Collaborative; Research; Seismicity; Equatorial; Mid

The sizes and locations of earthquakes recorded by eight hydrophones moored in the Equatorial Atlantic Ocean provide an unparalleled view of the seismicity of the poorly understood slow-spreading Mid-Atlantic Ridge in this region. The data also allow testing of the idea that earthquakes can be predicted at ocean transform faults, and they provide insight into how triple junctions (where three tectonic plates meet) work. The Equatorial Atlantic seafloor has not been studied extensively but is interesting for many reasons. First, the Mid-Atlantic Ridge axis is offset on some of the longest transform faults in the oceans. As an example, the Romanche transform is greater than 900 km long. In places, the transform offsets are so large that the total length of the transform faults is longer than the total length of the ridge axis. These fracture zones are extremely rugged, are important conduits for bottom water moving between the North and South Atlantic Ocean, and probably act as physical barriers blocking the transport of hydrothermal vent fauna along the ridge axis. The Equatorial Atlantic transforms are ideal for testing the short-term predictability of earthquakes at ocean transform faults and the results may help in understanding earthquakes on continental faults. A second interesting aspect of the region is that it contains the triple junction where the North America, South America, and Africa tectonic plates meet. The exact location of the triple junction is still a matter of debate, and this study will help to define its location. Third, the location of the plate boundary between the North America and South America plates is not known even though there is motion between the plates. The earthquakes recorded by the hydrophones provide important new information about the motion of these two plates, and how and where that motion is taking place. The hydrophone array also records a variety of natural and man-made noises and will facilitate a wide-range of studies beyond the scope of the proposed work. Examples include the use of ambient sound measurements to study various climate research topics, including estimating wave heights, rainfall intensity and wind speed during hurricanes. In addition, recorded whale vocalizations allow the distribution and migration of these animals to be tracked throughout the Equatorial Atlantic Ocean.

在赤道大西洋中系泊的八个漏洞记录的地震的尺寸和位置提供了无与伦比的观点，即该地区众所周知的慢速公布中大西洋山脊的地震性。 数据还允许测试可以在海洋变换断层中预测地震的想法，并且可以洞悉三重连接（三个构造板）的工作。赤道大西洋海底尚未得到广泛的研究，但由于许多原因而有趣。 首先，中大西洋山脊在海洋中最长的变换断层上被抵消。例如，romanche的变换大于900公里。在某些地方，变换偏移是如此之大，以至于变换故障的总长度长于脊轴的总长度。这些断裂带极度坚固，是在南大西洋之间移动的底水的重要管道，并且可能充当物理障碍，阻塞了沿着山脊轴的水热动物动物群的运输。赤道大西洋变换是测试海洋转化断层地震的短期可预测性的理想选择，结果可能有助于理解大陆断层的地震。该地区的第二个有趣的方面是，它包含北美，南美和非洲构造板相遇的三连接。三连接点的确切位置仍然是一个辩论问题，这项研究将有助于定义其位置。第三，即使板之间有运动，北美和南美板之间的板块边界的位置也不知道。言语记录的地震提供了有关这两个板的运动的重要新信息，以及该运动的发生方式和地点。 水文阵列还记录了各种天然和人造的噪音，并将促进超出拟议作品范围的广泛研究。 例子包括使用环境声音测量来研究各种气候研究主题，包括估计波高，降雨强度和飓风期间的风速。此外，记录的鲸鱼发声允许在整个赤道大西洋中跟踪这些动物的分布和迁移。