High-Resolution Imaging of Mantle Structure in the Western Pacific and Australasia

西太平洋和澳大利亚地幔结构的高分辨率成像

• 批准号: 9903043
• 负责人: Thomas Jordan
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2000-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9903043&HistoricalAwards=false
• 关键词: Resolution; Imaging; Mantle; Structure; Western

9903043JordanPrevious work has developed a new tomographic methodology that has been applied to two corridors in the south-central and western Pacific to obtain vertical (2D) tomograms of anisotropic shear velocities and discontinuity topography. These tomograms show features that are well correlated with topography and the geoid, but not in a manner expected from current models of oceanic mantle dynamics; these results thus have potentially profound implications for mantle dynamics. The first priority of the research proposed here will be to collect a comprehensive data set for the central and western Pacific and to invert these data for a high-resolution 3D model of the region. The data will include the travel times and dispersion characteristics of S-type body waves and reflections, upper-mantle guided waves, surface waves, and ScS reverberations. This research will also improve on the inversion methodologies in several ways: 1) by computing 3D sensitivity kernals, 2) by extending the inversion techniques to include amplitude variations, which will allow investigation of lateral variations in attenuation, and 3) by examining the effects of azimuthal anisotropy and its lateral heterogeneity.

9903043约旦以前的工作已经开发出一种新的层析成像方法，已被应用到两个走廊在中南部和西太平洋，以获得垂直（2D）的各向异性剪切速度和不连续地形的层析成像。 这些断层图像显示的功能，以及地形和大地水准面的相关性，但不是以预期的方式从目前的海洋地幔动力学模型，因此，这些结果有潜在的深远影响地幔动力学。 这里提出的研究的第一个优先事项将是收集太平洋中部和西部的综合数据集，并将这些数据转化为该区域的高分辨率三维模型。 这些数据将包括S型体波和反射波、上地幔导波、表面波和ScS混响的传播时间和色散特性。 这项研究还将在几个方面改进反演方法：1）通过计算3D灵敏度核，2）通过将反演技术扩展到包括振幅变化，这将允许调查衰减的横向变化，以及3）通过检查方位角各向异性及其横向不均匀性的影响。