CAREER: Estimating Temperature and Water Content of the North American Mantle from Geophysical Observations

这个项目考察了地幔温度和氢含量在地球动力学和板块构造中的作用。研究产品将用于对幼儿园至研究生的激励和教育。为此目的开发的工具将依次用于让研究人员探索研究产品和创建学生研究项目。地幔的对流模式，以及它们如何与构造板块运动和变形相结合，受到粘度的空间变化的影响。地幔温度和氢含量是影响粘度的主要参数。高温会降低粘度。从水中提取的含少量氢的矿物也比纯地幔矿物的粘性要小得多。这两个参数可以从地球物理，特别是地震观测的组合中估计出来。地震记录提供了支持或反对地震S波速度降低及其相关的刚性、异常泊松比以及北美之下的偏移和改变的地幔不连续的证据。这些观测数据受这两个参数的影响不同，将同时用于估算地幔温度和氢含量。这项工作将得到观测到的重力、推断的衰减、捕虏体分析和测量的热流的帮助。这项拟议的研究与美国长期的国家地球科学设施--地球望远镜协同工作。教学部分集中在一个信息亭，该信息亭将有三个互动部分，适用于广泛的教育水平和环境。互动将围绕以上总结的研究成果展开。拟议的教学充分利用了研究产品的强烈视觉方面，并与建议的研究相结合，因为1)研究产品用于让K-12儿童亲身接触地球科学，2)研究助理将促进K-12和本科生接受教学和公共沟通方面的培训，4)在信息亭与多层次观众的互动可以帮助指导研究，以及5)为教育和外展服务亭开发的互动工具将用于探索和解释研究产品。研究产品是北美地幔温度和氢含量的三维地震模型和导数模型。

This project examines the roles of mantle temperature and hydrogen content in geodynamics and plate tectonics. Research products will be used for stimulation and education of kindergarten through graduate students. Tools developed for this purpose will be used in turn to have researchers explore the research products and to create student research projects.Convection patterns in the Earth's mantle, and how they couple with tectonic plate motion and deformation, are directed by spatial variations in viscosity. Mantle temperature and hydrogen content are principal parameters affecting viscosity. High temperatures will lower viscosity. Minerals with small percentages of hydrogen, obtained from water, are also significantly less viscous than pure mantle minerals. These two parameters can be estimated from a combination of geophysical, in particular seismological observations. Seismograms provide evidence for or against reduced seismic S-wave velocity and associated rigidity, anomalous Poisson ratios, and offset and altered mantle discontinuities beneath North America. These observables are affected differently by the two parameters and will be used simultaneously to estimate mantle temperature and hydrogen content. This effort will be aided by observed gravity, inferred attenuation, xenolith analyses, and measured heat flow. The proposed research is synergistic with Earthscope - a long-term national Earth Sciences facility in the United States.Teaching components are centered around a kiosk that will have three interactive components, useful at a wide range of educational levels and environments. The interaction will be centered around the products of the research summarized above. The proposed teaching capitalizes on the strong visual facets of the research products and integrates with the proposed research because 1) the research products are used to expose K-12 children hands-on and eyes-open to Earth Science, 2) the research assistants that will facilitate the kiosk to K-12 and undergraduate students are thus trained in teaching and public communication, 4) the interactions with the multi-level audience at the kiosks could help steer research, and 5) the interactive tool developed for the education & outreach kiosk will be used to explore and interpret the research products. Research products are three-dimensional seismic models and derivative models for temperature and hydrogen content in the mantle under North America.