Along-Axis Continuity of Oceanic Detachment Faults

大洋拆离断层的沿轴连续性

基本信息

批准号：
1736547
负责人：
Ross Parnell-Turner
金额：
$ 9.54万
依托单位：
Woods Hole Oceanographic Institution
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2018-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1736547&HistoricalAwards=false
关键词：
Along Axis Continuity Oceanic Detachment

项目摘要

New seafloor is continuously formed at the center of Earth?s deep oceans, where the tectonic plates spread apart and cause hot magma to rise to the surface. Where the plates move apart more slowly, as happens over vast tracts of the Atlantic, Indian and Arctic oceans, deep-seated rocks from Earth?s mantle are exhumed, dragged up by slip on enormous, long-lived, faults called detachments and without significant eruption of lava. Creation of new oceanic seafloor by slip on these recently discovered faults is poorly understood, yet may play a fundamental role in paving a large part of our planet?s surface. One of the best ways to understand the behavior of these faults is to study the seismic waves caused by the small earthquakes that are triggered as the faults slip. This project examines earthquake data from a segment of the Mid-Atlantic Ridge near 13°N, where detachment faults are prevalent. The data were recorded by instruments placed on the seabed in 2016 by scientists from the UK, as part of a wider coordinated international effort to understand oceanic detachment faulting. This project fosters international collaboration between the USA, UK and France, and supports an early-career researcher.Observations of oceanic detachment faulting to date have mostly been limited to seabed sampling and mapping, leaving many questions about the structure and processes taking place beneath the seafloor unanswered. One of the most critical outstanding questions today is whether or not along-axis adjacent oceanic detachments are connected by a continuous fault in the sub-surface. An effective way to tackle this question is by studying naturally occurring seismicity generated as deformation takes place in the detachment fault system, which allows for direct imaging of fault structures and surfaces. While several local seismicity surveys have now been conducted at oceanic detachments, none of them has deployed a seismic network with sufficient aperture to constrain the along-axis extent of individual detachments. This project uses data from a 58 ocean bottom seismometer (OBS) deployment on the Mid-Atlantic Ridge at 13°N that extends ~30 km along the ridge axis and provides dense spatial coverage over two active detachment faults and the intervening ridge axis. This network, deployed by UK scientists to record airgun shots from an active-source seismic experiment, contains tens of thousands of local microearthquakes that will help determine whether or not the two core complexes at 13°20'N and 13°30'N are connected by a single fault surface.

在地球深海中心不断形成新的海底，那里的构造板散开并导致热岩浆升至表面。板块移动得更慢的地方，就像大西洋，印度和北极海洋的广阔区域一样，地球上的深座岩石被挖出，被巨大的，长寿的断层被拖到了被称为分离的断层，而没有大量的Lava爆发。通过在这些最近发现的故障上滑倒创造新的海洋海底的新海底，这是鲜为人知的，但在粘贴我们星球的大部分表面中可能发挥着基本作用。理解这些断层行为的最佳方法之一是研究由小地球唤醒引起的地震波，这些地震波被触发，后者是断层滑动的。该项目检查来自13°N附近中大西洋脊的一段的地球唤醒数据，那里的分离断层很普遍。该数据是由英国科学家在2016年在海床上放置的仪器记录的，这是一项广泛的国际努力，以了解海洋分队的断层。该项目促进了美国，英国和法国之间的国际合作，并支持早期研究员研究人员。迄今为止，海洋脱离过失的观察大部分仅限于海拔采样和映射，留下了许多有关在海底下未经提交的结构和过程的问题。当今最关键的问题之一是沿轴相邻的海洋支队是否通过地下表面的连续断层连接。解决这个问题的一个有效方法是研究由于变形发生在脱离故障系统中，从而可以直接对断层结构和表面进行直接成像。尽管现在已经在海洋脱离的地方进行了几项局部地震性调查，但它们都没有部署一个具有足够孔径的地震网络，以限制单个脱离的轴轴。该项目使用来自13°N的中大西洋山脊上58海洋底部地震计（OBS）部署的数据，该数据沿着山脊轴延伸约30 km，并在两个主动脱离故障和中间脊轴上提供密集的空间覆盖率。该网络由英国科学家部署，以记录活跃源地震实验的气枪射击，其中包含数以万计的本地微观Quake，这将有助于确定在13°20'n和13°30'n的两个核心复合物是否通过单个故障表面连接。

项目成果

期刊论文数量（2）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

The Final Stages of Slip and Volcanism on an Oceanic Detachment Fault at 13°48′N, Mid-Atlantic Ridge

大西洋中脊北纬 13°48° 处海洋滑脱断层上滑动和火山活动的最后阶段

DOI：
10.1029/2018gc007536
发表时间：
2018
期刊：
Geosystems
影响因子：
0
作者：
Parnell-Turner, R. E.;Mittelstaedt, E.;Kurz, M. D.;Jones, M. R.;Soule, S. A.;Klein, F.;Wanless, V. D.;Fornari, D. J.
通讯作者：
Fornari, D. J.

Genesis of corrugated fault surfaces by strain localization recorded at oceanic detachments