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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：
1839727
负责人：
Ross Parnell-Turner
金额：
$ 4.56万
依托单位：
University of California-San Diego Scripps Inst of Oceanography
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-07-01 至 2020-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1839727&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.

新的海底在地球中心不断形成？在深海中，构造板块分开，导致热岩浆上升到表面。在那里，板块移动得更慢，就像大西洋、印度洋和北冰洋的大片地区一样，地球上的深层岩石？在没有显著的熔岩喷发的情况下，地球的地幔被挖掘出来，被巨大的、长期存在的断层（称为推覆断层）的滑动向上拖曳。人们对这些最近发现的断层上的滑动产生新的海洋海底知之甚少，但可能在铺设我们星球的大部分地区方面发挥着重要作用？s表面。了解这些断层行为的最好方法之一是研究断层滑动时触发的小地震引起的地震波。该项目检查了来自大西洋中部海岭靠近13°N的一段的地震数据，在那里拆离断层很普遍。这些数据是由英国科学家于2016年放置在海底的仪器记录的，作为更广泛的国际协调努力的一部分，以了解海洋剥离断层。该项目促进了美国、英国和法国之间的国际合作，并支持了一位早期职业研究人员。迄今为止，对海洋拆离断层的观测大多仅限于海底取样和绘图，留下了许多关于海底下发生的结构和过程的问题没有得到解答。目前最关键的问题之一是，沿轴向相邻的大洋碎屑岩是否由地下连续断层连接。解决这个问题的一个有效方法是通过研究拆离断层系统中发生变形时产生的自然发生的地震活动，这可以直接对断层结构和表面进行成像。虽然现在已经在海洋地震台进行了几次地方地震活动调查，但没有一次部署了具有足够孔径的地震网络，以限制单个地震台的轴向范围。该项目使用的数据来自在大西洋中脊13°N处部署的58个海底地震仪，该地震仪沿脊轴延伸约沿着30公里，并在两个活动拆离断层和中间脊轴上提供密集的空间覆盖。这个网络由英国科学家部署，用于记录来自主动源地震实验的气枪射击，包含数万次局部微震，这将有助于确定位于13° 20 'N和13° 30' N的两个核心复合体是否由单个断层面连接。

项目成果

期刊论文数量（6）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Seismicity trends and detachment fault structure at 13°N, Mid-Atlantic Ridge

大西洋中脊北纬13°地震活动趋势和滑脱断层结构

DOI：
10.1130/g48420.1
发表时间：
2020
期刊：
Geology
影响因子：
5.8
作者：
Parnell-Turner, R.;Sohn, R.A.;Peirce, C.;Reston, T.J.;MacLeod, C.J.;Searle, R.C.;Simão, N.M.
通讯作者：
Simão, N.M.

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

DOI：
10.1016/j.epsl.2018.06.034
发表时间：
2018-09
期刊：
Earth and Planetary Science Letters
影响因子：
5.3
作者：
R. Parnell‐Turner;J. Escartín;J. Olive;Deborah K. Smith;S. Petersen
通讯作者：
R. Parnell‐Turner;J. Escartín;J. Olive;Deborah K. Smith;S. Petersen

Controls on the seafloor exposure of detachment fault surfaces

对滑脱断层面海底暴露的控制

DOI：
10.1016/j.epsl.2018.11.001
发表时间：
2019
期刊：
Earth and Planetary Science Letters
影响因子：
5.3
作者：
Olive, Jean-Arthur;Parnell-Turner, Ross;Escartín, Javier;Smith, Deborah K.;Petersen, Sven
通讯作者：
Petersen, Sven

Uppermost Mantle Velocity beneath the Mid-Atlantic Ridge and Transform Faults in the Equatorial Atlantic Ocean