CMG Collaborative Research: Fast Multipole Algorithms for Geophysical Stress Modeling and Their Use in Large-Scale Simulation of Earthquake Occurrence

CMG 协作研究：地球物理应力建模的快速多极算法及其在地震发生大规模模拟中的应用

• 批准号: 0934711
• 负责人: Terry Tullis
• 金额: $ 39.1万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0934711&HistoricalAwards=false
• 关键词: CMG; Collaborative; Research; Fast; Multipole

Fast Multipole Methods (FMMs) are widely used in many branches of science and technology, but there is a need for general-purpose, well-documented open source implementations of optimized versions of the method, suitable for use in the geosciences and other fields. One of the pressing needs for using FMMs is in conducting large-scale mathematical modeling of the occurrence of many earthquakes over a long period of time. Such simulations would produce a synthetic catalog of earthquakes, whose statistical properties, in both space and time, may be similar to the actual distribution of earthquakes that occur in nature. Such simulations are analogous to the global circulation models used by meteorologists and climate scientists to simulate weather and climate. In both cases, the objective is to use basic physical laws to simulate the behavior of a large and complex natural system. We have only recently gained enough knowledge about the complex non-linear geosystem that generates earthquakes that it is possible to conduct realistic earthquake simulations and test them against observed earthquake behavior. It is now possible that the simulations can be sufficiently realistic in detail and large enough in scale that they can be useful in understanding the physics of earthquakes as well as the probabilities of earthquake occurrence, understandings that have important societal benefits. This project will develop FMM algorithms and implement them for use with earthquake simulator codes. These improved codes will also be used to conduct much-improved earthquake simulations. The software we create will be useful for a variety of other applications in science and engineering beyond the one we focus on; we will provide our documented libraries with example problems on an open website and will publicize this to the scientific community.This project will develop, test, and apply new generations of efficient computer programs that can generate hitherto impossible long artificial histories of earthquakes. These histories will enable scientists to understand patterns of occurrence that can be used for estimating the hazard that earthquakes pose to human life and property. For example, the California Earthquake Authority, which sets earthquake insurance rates with billions of dollars of implications for California and the world, presently bases its estimates of the probability of earthquake occurrence on methodology that many experts feel is inadequate. The ability to create computer models that generate many long sequences of earthquakes is regarded by experts as the next important step in improving our understanding of when and where earthquakes may occur in many earthquake prone regions of the USA and abroad. In many ways this approach is similar to the computer-based forecasts of weather and climate that are presently much more advanced than are forecasts of earthquake occurrence. The project involves a new and tight collaboration between mathematicians and earthquake scientists who previously have been developing state-of-the-art approaches in their fields independently. The computer programs that are produced will enhance the ability or society to make fast and efficient computer models with benefits in a range of scientific and engineering applications in addition to their usefulness in understanding earthquakes. The programs will be documented, publicized, and made freely available on a web site.

快速多极方法（fmm）广泛应用于许多科学和技术分支，但需要通用的、文档完备的、适合于地球科学和其他领域的方法优化版本的开源实现。使用fmm的迫切需求之一是对长时间内许多地震的发生进行大规模的数学模拟。这样的模拟将产生一个合成的地震目录，其在空间和时间上的统计特性可能与自然界中发生的地震的实际分布相似。这种模拟类似于气象学家和气候科学家用来模拟天气和气候的全球环流模式。在这两种情况下，目标都是使用基本物理定律来模拟大型复杂自然系统的行为。直到最近，我们才对产生地震的复杂非线性地球系统有了足够的了解，从而有可能进行真实的地震模拟，并对观测到的地震行为进行测试。现在，模拟可能在细节上足够真实，在规模上足够大，从而有助于理解地震的物理性质以及地震发生的概率，这些理解具有重要的社会效益。该项目将开发FMM算法，并实现它们与地震模拟器代码一起使用。这些改进后的代码也将用于进行大大改进的地震模拟。我们创建的软件将在我们关注的科学和工程领域的各种其他应用中发挥作用；我们将在一个开放的网站上提供带有示例问题的文档库，并将其公布给科学界。这个项目将开发、测试和应用新一代高效的计算机程序，这些程序可以生成迄今为止不可能的长时间人工地震历史。这些历史将使科学家能够了解地震发生的模式，从而用于估计地震对人类生命和财产造成的危害。例如，加州地震局制定的地震保险费率对加州和全世界都有数十亿美元的影响，但目前它对地震发生概率的估计是基于许多专家认为不充分的方法。专家们认为，建立计算机模型产生许多长序列地震的能力，是提高我们对地震可能发生在美国和国外许多地震易发地区的时间和地点的理解的下一个重要步骤。在许多方面，这种方法类似于基于计算机的天气和气候预报，目前这种预报比地震发生的预报先进得多。该项目涉及数学家和地震科学家之间新的紧密合作，他们之前一直在各自领域独立开发最先进的方法。所产生的计算机程序将提高社会制作快速有效的计算机模型的能力，除了在了解地震方面有用外，还可在一系列科学和工程应用中受益。这些项目将被记录、公布，并在一个网站上免费提供。