CDI Type II/Collaborative Research: Ultra-high Resolution Dynamic Earth Models through Joint Inversion of Seismic and Geodynamic Data

CDI II 型/合作研究：通过地震和地球动力学数据联合反演的超高分辨率动态地球模型

• 批准号: 1028978
• 负责人: Michael Gurnis
• 金额: $ 55万
• 依托单位: California Institute of 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: 2010-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1028978&HistoricalAwards=false
• 关键词: CDI; Type; II; Collaborative; Research

Seismic and geodynamic observational data will be employed to infer a unified dynamic earth model through solution of the joint nonlinear inverse problem governed by high-resolution mantle convection and seismic wave propagation models. This will lead to a merging of the diverse data used to constrain plate tectonics and mantle convection, providing a new 4-D picture of earth's surface and interior over the last 50 million years. The inverse problem entails severe mathematical, computational, and geophysical challenges, which conventional methods are incapable of addressing. There are several parts of this project that are planned to overcome these challenges. We will devise inverse methods that can extract full information from the large volumes of seismic and geodynamic data by creating algorithms to solve the coupled full waveform seismic and geodynamic inverse problem, and use those methods to invert for global and regional earth models from broadband seismic and geodynamic data. We will develop inversion algorithms that can scale to the large numbers of CPU cores and complex memory hierarchies characterizing emerging multi-petaflop systems. We will also extend adaptive mesh refinement (AMR) ideas from large-scale forward simulation to the setting of large-scale inverse problems. Beyond the scientific impact, the project has a program of outreach and education that is highlighted by dissemination of 4-D animations of dynamic earth models. This project fits within the "From Data to Knowledge" and "Understanding Complexity" themes of the CDI Program.The earth is a four-dimensional dynamic system where mantle convection drives plate tectonics and continental drift and, in turn, controls much activity ranging from the occurrence of earthquakes and volcanoes to mountain building and long-term sea level change. Despite the central role mantle convection plays in our understanding of earth, we have enormous first-order gaps in our knowledge, with questions that are as basic as what are the principal driving and resisting forces on plate tectonics to what is the energy balance of the planet as a whole. However, rapidly-expanding volumes of geophysical data, the arrival of the petaflop computing era, and the emergence of high-resolution forward model simulation capabilities now provide an opportunity to merge the geophysical data into dynamic earth models to greatly enhance our understanding of earth structure. This project could catalyze a shift in the field of geodynamics, since it will lead to rigorous inference of earth models from data employing high-resolution forward models. Moreover, the project could be transformative for many other fields with similar needs, through the development of parallel mesh algorithms for large-scale inverse problems, scalable methods for large-scale nonlinear inverse problems, and inverse methods for joint inversion of data for large complex multi-physics forward models. All of these computational/mathematical advances will benefit a much wider community of scientists working on a much broader set of problems than the ones encountered in this project.

利用地震和地球动力学观测资料，通过求解高分辨率地幔对流和地震波传播模型所支配的联合非线性反问题，推导出统一的地球动力学模型。这将导致用于约束板块构造和地幔对流的各种数据的合并，提供过去5000万年来地球表面和内部的新的4维图像。反问题需要严峻的数学、计算和地球物理挑战，而传统方法无法解决这些挑战。该项目有几个部分计划用来克服这些挑战。我们将通过建立求解全波形地震和地球动力学耦合反问题的算法，设计能够从海量地震和地球动力学数据中提取全部信息的反演方法，并使用这些方法从宽带地震和地球动力学数据中反演全球和区域地球模型。我们将开发可扩展到大量CPU核心和复杂内存层次的反转算法，以表征新兴的多Petaflop系统。我们还将把自适应网格加密(AMR)的思想从大规模正向模拟扩展到大规模反问题的设置。除了科学上的影响，该项目还有一个外展和教育计划，突出的是传播动态地球模型的4-D动画。这个项目符合CDI计划的“从数据到知识”和“理解复杂性”的主题。地球是一个四维动力系统，地幔对流驱动板块构造和大陆漂移，进而控制从地震和火山的发生到造山和长期海平面变化的许多活动。尽管地幔对流在我们对地球的理解中发挥着核心作用，但我们在知识上存在着巨大的一阶差距，存在着一些基本的问题，比如什么是板块构造的主要驱动力和阻力，以及地球整体的能量平衡是什么。然而，快速膨胀的地球物理数据量、千万亿次浮点计算时代的到来以及高分辨率正演模型模拟能力的出现，现在为将地球物理数据合并到动态地球模型中提供了机会，以极大地提高我们对地球结构的理解。这个项目可能会促进地球动力学领域的转变，因为它将导致使用高分辨率正演模型的数据对地球模型进行严格的推断。此外，通过开发用于大规模逆问题的并行网格算法、用于大规模非线性逆问题的可扩展方法以及用于大型复杂多物理正演模型的联合数据反演方法，该项目可能对许多具有类似需求的其他领域具有变革性。所有这些计算/数学进步将使更多的科学家受益，他们从事的问题比这个项目中遇到的问题要广泛得多。