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.

地球的外层由刚性构造板组成，例如破裂的蛋壳。这些板在行星表面上滑动在下面的较弱，更热的层上。从刚性板到下面的地幔的过渡是板块构造和我们在地球上的存在的基础。但是，板的定义，即它们的厚度，定义机制和与下层层的耦合程度并不是众所周知。我将使用全局地震成像来理解地球海洋板的厚度和定义机制。海板覆盖了地球表面的70％，但鉴于远程性，很少以高分辨率映射，并且将地震仪的部署到4公里深的海洋底部的困难和成本。我已经开发了一种新方法来绘制车站覆盖范围稀疏的位置的板块，因为它在海洋下方。我使用SS波形，这是一个S波，一次在地球表面弹跳一次。 SS波特征的细微变化提供了有关BouncePoint区域中构造板底座的深度和特征的信息。我将使用新汇编的全局数据库（1990-2011），该数据库的大小几乎是4TB，代表我先前研究中的数据大约四倍。意义在于，我将在所有海洋盆地中拥有几乎完美的分辨率，从而实现了全球比较和构造板块的统一观点。该板的定义对影响人类生存的许多过程具有影响。它对板的移动方式具有根本的控制。这包括地震，火山和海啸的产生。因此，更好的理解将导致更好的危害评估和缓解自然灾害。另外，板厚度和强度直接影响构造板的隆起和沉降。这些力量影响了山区建设和海平面上升，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，并阐明基本问题。我将更好地理解构造板的定义，包括其形成和进化。了解海板对于任何构造环境都是至关重要的，因为它们可能在大陆的形成中发挥重要作用。总体而言，这项工作将加深我们对板块构造学的理解。