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Global Seismic Imaging of the Oceanic Plates

海洋板块的全球地震成像

基本信息

批准号：
NE/K000985/1
负责人：
Catherine Rychert
金额：
$ 7.4万
依托单位：
University of Southampton
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FK000985%2F1
关键词：
Global Seismic Imaging Oceanic Plates

项目摘要

The outer layer of the earth is composed of rigid tectonic plates, like a cracked eggshell. These plates slide around the surface of the planet over a weaker, hotter layer below. The transition from rigid plate to the mantle below is fundamental to plate tectonics and our existence on the planet. However, the definition of the plate, i.e., their thickness, defining mechanism, and degree of coupling to the layer below are not well-known.I will use global seismic imaging to understand the thickness and defining mechanism of the Earth's oceanic plates. The ocean plates cover 70% of Earth's surface, yet are rarely mapped at high resolution given the remoteness, and the difficulty and cost of deploying seismometers to the bottom of a 4 km deep ocean. I have developed a new methodology to map the plates in locations where station coverage is sparse, as it is beneath the oceans. I use the SS waveform, which is an S wave that has bounced once at Earth's surface. Subtle variations in the character of the SS wave give information on the depth and character of the base of the tectonic plate in the region of the bouncepoint.I will use a newly compiled global database (1990 - 2011) which is nearly 4TB in size, and represents about four-times the data in my previous investigations. The significance is that I will be have nearly perfect resolution across all ocean basins, enabling global comparisons and a unified view of the tectonic plate.The definition of the plate has implications for many processes that impact human existence. It has a fundamental control on how plates move. This includes the generation of earthquakes, volcanoes, and tsunamis. Therefore a better understanding will lead to better hazard assessment and mitigation of natural disasters. In addition, plate thickness and strength directly affects uplift and subsidence of the tectonic plate. These forces impact mountain building and sea level rise, and are therefore important factors in understanding climate change. The results from this study will change text books, and clarify fundamental questions. I will develop a better understanding of the definition of a tectonic plate, including its formation and evolution. Understanding the ocean plates is fundamental to any tectonic setting in that they likely play a large role in the formation of the continents. Overall, this work will deepen our understanding of plate tectonics.

地球的外层是由坚硬的构造板块组成的，就像一个破裂的蛋壳。这些板块在行星表面滑动，下面是一个较弱，较热的层。从刚性板块到下面的地幔的过渡是板块构造和我们在地球上生存的基础。然而，板的定义，即，它们的厚度、定义机制和与下面地层的耦合程度还不为人所知。我将利用全球地震成像来了解地球海洋板块的厚度和定义机制。海洋板块覆盖了地球表面的70%，但由于位置偏远，以及在4公里深的海底部署地震仪的难度和成本，很少有高分辨率的地图。我已经开发了一种新的方法来绘制板块的位置，站覆盖稀疏，因为它是在海洋之下。我使用SS波形，这是一个S波，在地球表面反弹一次。SS波特征的细微变化提供了关于反弹点区域构造板块底部的深度和特征的信息。我将使用一个新编制的全球数据库（1990 - 2011），该数据库的大小接近4 TB，约为我以前调查数据的4倍。其意义在于，我将在所有海洋盆地中获得近乎完美的分辨率，从而实现全球比较和构造板块的统一观点。板块的定义对影响人类生存的许多过程都有影响。它对板块的运动有着根本的控制。这包括地震、火山和海啸的产生。因此，更好地了解自然灾害将导致更好的灾害评估和减灾。另外，板块的厚度和强度直接影响着板块构造的升降。这些力量影响着造山运动和海平面上升，因此是理解气候变化的重要因素。这项研究的结果将改变教科书，并澄清基本问题。我将更好地理解构造板块的定义，包括它的形成和演化。了解海洋板块是任何构造环境的基础，因为它们可能在大陆的形成中发挥重要作用。总的来说，这项工作将加深我们对板块构造的理解。