Toward Exascale Global Adjoint Tomography

迈向百亿亿次全球伴随断层扫描

基本信息

批准号：
1644826
负责人：
Jeroen Tromp
金额：
$ 54.75万
依托单位：
Princeton University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-01-01 至 2019-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1644826&HistoricalAwards=false
关键词：
Toward Exascale Global Adjoint Tomography

项目摘要

This research involves the development of open-source software for simulations of seismic wave propagation inside the Earth. Such simulations may be used for quantitative seismic hazard assessment, visualizations for outreach and educational activities, as well as a basis for seismic tomography. Like medical tomography, the goal of seismic tomography is to image the Earth's interior on all scales, from hydrocarbon fields in exploration seismology to Earth's mantle in global seismology, to help us understand our planet's inner workings and evolution. As a broader impact this project will publish earthquake wave animations online in near real-time for events with magnitudes of 5.5 and greater at Princeton University's Near Real Time Seismicity Portal (GlobalShakeMovie) .The main goal of this research is to further develop global seismic tomography using complete seismic waveforms and adjoint-state methods by enabling massive data assimilation and harnessing the largest and fastest available computers. Using a pilot dataset of 253 earthquakes, a first-generation global tomographic model based on "adjoint tomography", an iterative full-waveform inversion technique was built. Based on this experience, a next-generation global model will be constructed by assimilating full waveform data from thousands of earthquakes that were well recorded by broadband global and regional seismographic networks. Prior NSF support demonstrated the feasibility of regional adjoint tomography for isotropic heterogeneity, anelasticity, and azimuthal anisotropy. Similar inversions on a global scale will be done through secured access to the necessary computational hardware through the Department of Energy INCITE program. This research supports a portion of the required human resources, where the rate-limiting steps in this ambitious endeavor are data quality control, I/O, and workflow management. Four main tasks will be tackled bearing these obstacles in mind: 1) prepare and further develop the open source spectral-element seismic wave propagation solvers SPECFEM3D and SPECFEM3D_GLOBE for exascale simulations; 2) further develop the Adaptable Seismic Data Format (ASDF) for fast I/O; 3) further develop the inversion & migration toolkit SeisFlows by taking advantage of the open source Structured Query Language database engine SQLight and existing workflow management tools, such as Pegasus; and 4) perform global adjoint seismic tomography with a database of thousands of earthquakes at a shortest period of 9 s. Task 4 encompasses the main goal of the proposal, but it cannot be completed without simultaneously addressing the other tasks.

这项研究涉及开发开源软件，以模拟地球内的地震波传播。这些模拟可用于定量地震危险评估，外展和教育活动的可视化以及地震层析成像的基础。像医学断层扫描一样，地震层析成像的目的是在各个尺度上对地球的内部进行想象，从勘探地震学的碳氢化合物田到全球地震学的地球地幔，以帮助我们了解地球的内部作用和进化。作为更广泛的影响，该项目将在近实时在线发布地震波动画，以实时为5.5幅度，在普林斯顿大学的近实时地震活动门户网站（Globalshakemovie）中，这项研究的主要目的是进一步开发全球地震层析成像，以实现全球地震波形，并通过实现大量数据和封装来实现量度和封装，并构成量度的范围。使用253次地震的试验数据集，这是一种基于“伴随断层扫描”的第一代全球层析成像模型，建立了一种迭代全波反转技术。基于这一经验，将通过吸收来自数千个地震的完整波形数据来构建下一代全球模型，而宽带全球和区域地震学网络记录了数千个地震。先前的NSF支持证明了区域伴随断层扫描对各向同性异质性，弹性性和方位角各向异性的可行性。在全球范围内的类似倒置将通过通过能源煽动计划获得必要的计算硬件的安全访问来完成。这项研究支持了所需的人力资源的一部分，在此雄心勃勃的努力中，限制速率的步骤是数据质量控制，I/O和工作流程管理。考虑到这些障碍，将解决四个主要任务：1）准备并进一步开发开源光谱元件地震波传播求解器SpecFem3D和SpecFem3D_Globe用于Exascale模拟； 2）进一步为快速I/O开发适应性的地震数据格式（ASDF）； 3）通过利用开源结构化查询语言数据库SQLIGHT和现有的工作流管理工具（例如Pegasus），进一步开发了反转和迁移工具包Seisflows； 4）在最短的9 s时期，使用数千个地震的数据库进行全球伴随地震层析成像。任务4涵盖了该提案的主要目标，但是如果不同时解决其他任务，就无法完成。