Mantle Anisotropic Structure and Dynamics Beneath the Western United States: Constraints from Shear-wave Splitting Analysis

美国西部地幔各向异性结构和动力学：剪切波分裂分析的约束

• 批准号: 0952064
• 负责人: Kelly Liu
• 金额: $ 18.59万
• 依托单位: Missouri University of Science and Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0952064&HistoricalAwards=false
• 关键词: Mantle; Anisotropic; Structure; Dynamics; Beneath

One of the major discoveries in the geological science made over the past 50 years is that the crustal and the upper-most mantle of the Earth are divided into tens of 'pieces', or tectonic plates. Movement of the plates against one another is responsible for the formation of ocean basins, mountain ranges, rifted valleys, volcanoes, and earthquakes. In spite of numerous studies, however, the forces that are driving the movement of the plates remain unresolved. The ongoing project is designed to provide critical information on the driving mechanism of plate motion, by measuring the strength and direction of the fabrics formed by the movement of the plates. A database of thousands of shear-wave splitting parameters, which are measures of deformation in the lithosphere and flow in the underlain asthenosphere, is being established as an updated version of an existing shear-wave splitting database (NA-SWS-1.1 which can be accessed at http://www.mst.edu/~liukh/SWS) that the PI established for North America. The new database, like its first version, will be made public as soon as possible over the course of the project. The researchers involved in the current project are collecting geological and geophysical information to interpret the shear-wave splitting observations. Major scientific issues to be addressed by the proposed study include whether the western US is underlain pervasively by two-layer anisotropy, why the Colorado Plateau and adjacent areas show complex anisotropy, and what are the characteristics of mantle structure and dynamics beneath the transitional zone between the tectonically active western US and apparently inactive Great Plains.

在过去50年中，地质科学中的主要发现之一是，地壳和最高地球的地幔被分为几十个“碎片”或构造板。盘子彼此的运动是造成海盆，山脉，裂谷，火山和地震的形成。 然而，尽管进行了许多研究，但驱动板运动的力仍未解决。正在进行的项目旨在通过测量板运动形成的织物的强度和方向来提供有关板运动驱动机制的关键信息。 A database of thousands of shear-wave splitting parameters, which are measures of deformation in the lithosphere and flow in the underlain asthenosphere, is being established as an updated version of an existing shear-wave splitting database (NA-SWS-1.1 which can be accessed at http://www.mst.edu/~liukh/SWS) that the PI established for North America.与第一个版本一样，新数据库将在项目过程中尽快公开。参与当前项目的研究人员正在收集地质和地球物理信息，以解释剪切波分裂的观察结果。拟议的研究要解决的主要科学问题包括美国西部是否在两层各向异性上遍布底层，为什么科罗拉多高原和邻近的地区为何表现出复杂的各向异性，以及在构件结构和动态的特征是什么是构件活跃的西方我们和显而易见的不活跃的层次上的过渡区域下的过渡区域。