CAREER: Mantle Seismic Structure Beneath North America and Evolving Seismcity in the Raton Basin

研究方向：北美地幔地震结构和拉顿盆地地震活动性演化。该项目将支持两条研究方向。第一种方法利用了最近和正在进行的社区驱动的宽带地震数据收集，系统地覆盖了北美一半以上的地区。第二个重点关注Raton盆地的地震活动，该盆地位于新墨西哥州和科罗拉多州边界，是天然气生产和废水注入地区。这两方面的研究都包括为本科生和研究生提供教育机会，以及扩大活动，以提高地球科学，特别是地球物理学在阿尔伯克基周围中学的代表性。第一线研究的目标将通过地幔结构的地震调查及其对北美地下热化学对流过程的影响来实现，特别是考虑到在一个不寻常的层中存在大量地球化学水库的潜在证据。700千米深的称为地幔过渡带。这一层的性质可以为地球上地表水的演化限制提供新的见解。由于持续的对流，美国的历史和部分熔融的发生。研究的第二条线将包括在项目期间收集和分析Raton盆地的地震数据，以测试地震的时空模式和机制如何响应不同的废水注入速率、增加的累积注入量和小的自然瞬态应力。这个项目吗?他的两个主要研究目标是：1)验证北美地幔过渡带是地球化学主要储层的假设；2)约束Raton盆地地震活动性对废水注入的时间依赖性响应。这两条研究路线都与教育目标相结合，即增加新墨西哥州中学生到研究生的不同层次学生对地球科学研究的参与。研究的第一线将使用一套EarthScope地震数据的相互依赖分析，包括连续和横向零星界面的映射，界面清晰度和振幅的映射变化，以及限制三维速度结构对界面成像的影响。通过与矿物物理学家和地球动力学家的合作，将对水合过渡假说进行定量评估。研究的第二条线涉及对Raton盆地地震活动性的扩展观察和分析，该盆地地震活动性的增加与污水注入量的增加有关。该组件将实现更高的分辨率和更长期的观测发震变形和废水注入之间的反馈。年度班级研究项目和本科生实习生将主要进行数据收集和分析，以约束活动断层分布、震源机制、震级分布和外部触发易感性的时间变化。在许多学生第一次接触地球科学的中学阶段，基于地点的教育工作将使用Raton盆地和EarthScope的数据来增加对地球科学研究的接触，并在代表性不足的人群中提高对地球科学职业机会的认识。

CAREER: Mantle seismic structure beneath North America and evolving seismicity in the Raton BasinThis project will support two lines of research. The first takes advantage of recent and ongoing community-driven collection of broadband seismic data systematically covering more than half of North America. The second focuses on earthquake activity in the Raton Basin, which is on the New Mexico-Colorado border and an area of natural gas production and wastewater injection. Both lines of research include educational opportunities for undergraduate and graduate students as well as outreach activities to improve the representation of Earth science and particularly geophysics in middle schools around Albuquerque. The goals of the first line of research will be achieved by seismic investigation of mantle structure and its implications for thermal and chemical convection processes beneath North America, with particular consideration of potential evidence for or against a substantial geochemical reservoir of water in an unusual layer about 400?700 km deep referred to as the mantle transition zone. The properties of this layer could provide new insights into limits on the evolution of surface water over Earth?s history and occurrence of partial melting as a result of ongoing convection. The second line of research will involve collection and analysis of seismic data in the Raton Basin over the duration of this project in order to test how spatial and temporal patterns and mechanisms of earthquakes respond to varying wastewater injection rates, increasing cumulative injected volume, and small natural transient stresses.This project?s two main research goals are: 1) to test the hypothesis that the mantle transition zone beneath North America is a major geochemical reservoir of water and 2) constrain the time dependent response of Raton Basin seismicity to wastewater injection. Both lines of research are integrated with the educational goal of increasing participation in geoscience research among the diverse population of New Mexico students at levels ranging from middle school to graduate school. The first line of research will use a suite of interdependent analyses of EarthScope seismic data including mapping of continuous and laterally sporadic interfaces, mapping variations in the sharpness and amplitude of interfaces, and constraining the influence of 3-D velocity structure on interface imaging. Quantitative assessment of the hydrated transition hypothesis will be conducted through collaborations with mineral physicists and geodynamicists. The second line of research involves extended observation and analysis of seismicity in the Raton Basin, which has hosted an increase in seismicity correlated with increased wastewater injection. This component will enable higher resolution and longer-term observations of feedbacks between seismogenic deformation and wastewater injection. Annual class research projects and undergraduate interns will primarily conduct data collection and analysis to constrain temporal variations in the distribution of active faults, source mechanisms, magnitude distribution, and susceptibility to external triggering. Place-based education efforts at the middle school level, where many students first encounter the geosciences, will use Raton Basin and EarthScope data to enhance exposure to geoscience research and awareness of geoscience career opportunities among underrepresented populations.