CAREER: Developing a Multi-Parameter Seismic Model of North America

职业：开发北美多参数地震模型

• 批准号: 2042098
• 负责人: Hejun Zhu
• 金额: $ 53.67万
• 依托单位: University of Texas at Dallas
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2042098&HistoricalAwards=false
• 关键词: CAREER; Developing; Multi; Parameter; Seismic

Jointly constraining and interpreting multiple seismic parameters enables geophysicists to better investigate physical properties of Earth materials. Such studies may allow scientists to infer distributions of temperature, water content, and deformation. This project aims to develop a multi-parameter seismic model for North America by using state-of-the-art full waveform inversion technology and high-quality waveform records collected by the USArray over the past decade. This community-shared, multi-parameter seismic model will include 3-D variations in velocities, anisotropy, shear attenuation and the associated uncertainties. Jointly interpreting these parameters will enable the investigators to address important scientific problems related to depth-dependent anisotropy and water distribution within the mantle transition zone. Solving these issues is important for our understanding of the physical characteristics of the lithosphere, asthenosphere and mantle transition zone. Furthermore, this CAREER project will support an early career PI and several Ph.D. graduate and undergraduate students. The PI will promote high-performance computation in Geophysics education, engage undergraduate students in research and participate in UTD STEM summer camps for high school students. The Dallas area has large African, Hispanic and Asian American communities, the PI will attract high school students from these communities to participate this summer camp program. The developed multi-parameter seismic model will be shared online for public and research usages. Results from this project will be disseminated via peer-reviewed publications and presentations at national/international meetings.This project will combine full waveform inversion and high-quality USArray records to construct a comprehensive seismic model for North America, which will enable the team to tackle the following scientific problems. (1) The 3-D azimuthal anisotropy structure in the developed comprehensive model will enable us to distinguish “frozen-in” lithospheric deformation and present-day asthenospheric flows. In addition, jointly interpreting radial and azimuthal anisotropy enables them to test the anisotropy cause hypothesis for the mid-lithosphere discontinuity; (2) Considering the high water solubilities of wadsleyite and ringwoodite, the mantle transition zone might act as a huge water reservoir inside the Earth. Seismic attenuation has been considered as an important proxy for delineating the distribution of water. By jointly interpreting velocity and attenuation results taken from the developed comprehensive model, this project aims to answer the question: “Is the mantle transition zone underneath North America highly hydrated?” (3) Quantifying uncertainty and resolution is still challenging in full waveform inversion applications. This project will develop algorithms to efficiently evaluate the posterior covariance and resolution matrix, which will be applied to quantify uncertainty of the developed, multi-parameter seismic model of North America. The PI will also promote interactions between students and experts from the energy industry through workshops and summer internships. This project will enable the PI to train graduate and undergraduate students for seismology related research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

联合约束和解释多个地震参数使地球物理学家能够更好地研究地球材料的物理特性，此类研究可以让科学家推断温度、含水量和变形的分布。该项目旨在通过以下方式开发北美的多参数地震模型。该社区共享的多参数地震模型将使用最先进的全波形反演技术和 USArray 在过去十年中收集的高质量波形记录。速度、各向异性、剪切衰减和相关不确定性的变化将使研究人员能够解决与地幔过渡带内的深度相关的各向异性和水分布相关的重要科学问题。此外，该职业项目将支持一名早期职业 PI 和几名博士生和本科生。达拉斯地区有大量非洲裔、西班牙裔和亚裔美国人社区，PI 将吸引这些社区的高中生参加本次夏令营。开发的多参数地震模型将在线共享以供公众和研究使用，该项目的结果将通过同行评审的出版物和在国家/国际会议上的演讲进行传播。该项目将结合全波形反演和研究。高质量的USArray记录来构建北美的综合地震模型，这将使​​团队能够解决以下科学问题（1）开发的综合模型中的3D方位各向异性结构将使我们能够区分“冻结-地震”。此外，联合解释径向和方位各向异性使他们能够检验岩石圈中部的各向异性成因假说。 (2)考虑到瓦兹利石和尖伍德石的高水溶性，地幔过渡带可能作为地球内部的一个巨大的水库，通过联合解释速度被认为是描述水分布的重要指标。以及从开发的综合模型中得到的衰减结果，该项目旨在回答以下问题：“北美下方的地幔过渡带是否高度水化？（3）量化不确定性和分辨率仍然存在”该项目将开发有效评估后验协方差和分辨率矩阵的算法，该算法将用于量化北美开发的多参数地震模型的不确定性。PI 还将促进学生之间的互动。来自能源行业的专家通过研讨会和暑期实习反映，该项目将使 PI 能够培训研究生和本科生进行地震学相关研究。该奖项是 NSF 的法定使命，并通过使用基金会的智力优势和评估进行评估，被认为值得支持。更广泛的影响审查标准。

项目成果

Constructing a 3‐D Radially Anisotropic Crustal Velocity Model for Oklahoma Using Full Waveform Inversion

• DOI: 10.1029/2023jb026992
• 发表时间: 2023-11
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Shuo Zhang;Hejun Zhu

Monitoring Seasonal Fluctuation and Long‐Term Trends for the Greenland Ice Sheet Using Seismic Noise Auto‐Correlations

使用地震噪声自动相关性监测格陵兰冰盖的季节性波动和长期趋势

• DOI: 10.1029/2022gl102146
• 发表时间: 2023
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Luo, Bingxu;Zhang, Shuo;Zhu, Hejun
• 通讯作者: Zhu, Hejun

Time‐Lapse Imaging of Coseismic Ruptures for the 2019 Ridgecrest Earthquakes Using Multiazimuth Backprojection With Regional Seismic Data and a 3‐D Crustal Velocity Model

• DOI: 10.1029/2020gl087181
• 发表时间: 2020-05
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Jidong Yang;Hejun Zhu;D. Lumley

Monitoring Terrestrial Water Storage, Drought and Seasonal Changes in Central Oklahoma With Ambient Seismic Noise

• DOI: 10.1029/2023gl103419
• 发表时间: 2023-09
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Shuo Zhang;Bingxu Luo;Y. Ben‐Zion;David E. Lumley;Hejun Zhu