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

职业生涯：北美地幔地震结构和拉顿盆地地震活动演变这个项目将支持两个研究方向。第一个利用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。第二个重点是拉顿盆地的地震活动，该盆地位于新墨西哥州和科罗拉多州的边界，是天然气生产和废水注入的地区。这两个研究方向都包括为本科生和研究生提供教育机会，以及为提高地球科学，特别是地球物理学在阿尔伯克基周围中学的代表性而开展的外联活动。第一线研究的目标将通过对北美地幔结构及其对热和化学对流过程的影响的地震调查来实现，特别是考虑支持或反对在约400？700公里深的称为地幔过渡带的不寻常层中存在大量水的潜在证据。这一层的性质可以为了解地球上地表水演化的极限-S的历史和持续对流导致的部分融化的发生提供新的见解。第二条研究线将涉及收集和分析拉顿盆地在该项目期间的地震数据，以测试地震的时空模式和机制对不同的污水注入量、不断增加的累积注入量和小的自然瞬时应力的响应。该项目？S有两个主要的研究目标：1)检验北美地幔过渡带是主要的水的地球化学储集层的假设；2)限制拉顿盆地地震活动对污水注入的时间依赖响应。这两条研究路线都与教育目标相结合，即在新墨西哥州从中学到研究生院的不同人群中增加对地球科学研究的参与。第一条研究路线将使用一套对EarthScope地震数据的相互依赖分析，包括绘制连续的和横向零星的界面，绘制界面的锐度和幅度的变化，以及限制三维速度结构对界面成像的影响。水化转变假说的定量评估将通过与矿物物理学家和地球动力学家的合作进行。第二项研究涉及对拉顿盆地的地震活动进行广泛的观察和分析，该盆地的地震活动随着废水注入的增加而增加。这一组成部分将能够对孕震变形和废水注入之间的反馈进行更高的分辨率和更长期的观察。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，以限制活动断层的分布、震源机制、震级分布和对外部触发的敏感性的时间变化。许多学生第一次接触地球科学的地方教育工作将使用Raton盆地和EarthScope的数据，以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.