CAREER: Integrating Seismic Constraints on Continental Upper Mantle

本项目的重点是利用地震体波和面波研究三个克拉通地区。研究区域包括卡普瓦尔克拉通、北美克拉通东部和怀俄明州克拉通。这些地区的区域地震台网，如南部非洲的SASE台网、加拿大东南部的北极星台网以及怀俄明州和蒙大拿州的美国台阵，为研究提供了丰富的宽带地震数据。该项目的研究部分包括：(1)进行瑞利波和乐夫波反演，以确定南部非洲、北美东部和怀俄明州克拉通的三维剪切波速度、方位各向异性和径向各向异性结构；(2)进行正演模拟，利用剪切波分裂和面波约束来确定南部非洲下方的端元各向异性模型；(3)发展体波和面波的联合反演方法，并将其应用于SASE和北极星数据集。由该项目建立的高分辨率地震模型将对克拉通岩石圈的性质提供新的认识，并为大陆克拉通的动力学过程提供新的见解。这个项目中修改和开发的反演方法可以很容易地应用于美国阵列和其他区域地震台阵的地震数据。这个职业发展项目的另一个重要组成部分是教育。这些教育活动包括：(1)每学期为休斯顿大学物理地质课的学生提供地震学工作坊；(2)开发一门新的研讨会课程和一个关于大陆克拉通的网站；(3)开发关于反演和面波概念的网络模块；以及(4)在校园内安装地震仪。这些活动将向广大受众介绍地震地震学，帮助招收地球物理学专业的学生，改善密歇根大学地球物理的教学和学习环境，并为社区提供有关大陆克拉通的新网络资源。这些教育产品将在网上提供，以便在地球科学界广泛使用。

This project focuses on studying three cratonic regions using seismic body and surface waves. The study areas include the Kaapvaal craton, the eastern part of the North America craton, and the Wyoming craton. Regional seismic networks in these regions, such as the SASE array in southern Africa, the POLARIS network in southeastern Canada, and the USArray in Wyoming and Montana, provide abundant broadband seismic data for the studies. The research components of the project are (1) to perform Rayleigh and Love wave inversions to determine 3-D shear-wave velocity, azimuthal anisotropy, and radial anisotropy structure in southern Africa, eastern North America, and the Wyoming craton, (2) to conduct forward modeling to determine endmember anisotropic models beneath southern Africa using shear-wave splitting and surface wave constraints, (3) to develop a joint inversion method for body and surface waves and apply it to the SASE and the POLARIS data sets. High resolution seismic models constructed from this project will cast new light on properties of cratonic lithosphere and provide new insights into the dynamic process of continental cratons. The inversion methods that are modified and developed in this project can be easily applied to seismic data from the USArray and other regional seismic arrays.Another significant component of this CAREER development project is education. The education activities include (1) offering a seismology workshop for students in the Physical Geology class each semester at the University of Houston, (2) developing a new seminar course and a website about continental cratons, (3) developing web-based modules about inversion and surface wave concepts, and (4) installing a seismograph on campus. These activities will introduce earthquake seismology to a broad audience, help to recruit geophysics students, enhance the teaching and learning environment in geophysics at UH, and provide the community with a new web source about continental cratons. The educational products will be made available online so that they can be widely used in the earth science community.