Along-Axis Continuity of Oceanic Detachment Faults

在地球的中心不断形成新的海底？在那里，构造板块分开，导致热岩浆上升到海面。在哪里板块分离得更慢，就像在大西洋、印度洋和北冰洋的大片土地上发生的那样，在地球深处的岩石上？美国的地幔被挖掘出来，被巨大的、长期存在的断层（称为分离断层）所拖起，没有明显的熔岩喷发。由于这些最近发现的断层的滑动而形成的新的海洋海底，人们知之甚少，但可能在铺设我们星球的大部分土地方面发挥了根本作用。年代的表面。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所引起的地震波。这个项目检查了靠近13°N的大西洋中脊的一段地震数据，那里剥离断层普遍存在。这些数据是由英国科学家于2016年在海底放置的仪器记录的，这是了解海洋分离断层作用的更广泛的国际协调努力的一部分。该项目促进了美国、英国和法国之间的国际合作，并支持一名早期职业研究人员。迄今为止，对海洋剥离断层的观察大多局限于海底取样和测绘，留下了许多关于海底结构和海底下发生的过程的问题。当今最关键的悬而未决的问题之一是，沿轴线相邻的海洋分离体是否由地下的连续断层连接起来。解决这个问题的一个有效方法是研究剥离断层系统中发生变形时产生的自然地震活动性，这可以直接成像断层结构和表面。虽然目前已经在海洋考察队进行了几次当地地震活动调查，但没有一个考察队部署了具有足够孔径的地震网，以限制个别考察队沿轴的范围。该项目使用了部署在13°N的大西洋中脊上的58海底地震仪（OBS）的数据，该数据沿脊轴延伸约30公里，并提供了两个活动剥离断层和中间脊轴的密集空间覆盖。该网络由英国科学家部署，用于记录来自有源地震实验的气枪射击，包含数万个局部微地震，将有助于确定13°20′n和13°30′n的两个核心复合是否由单个断层表面连接。

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.