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

9903043约旦以前的工作开发了一种新的层析成像方法，该方法已应用于太平洋中南部和西部的两个走廊，以获得各向异性剪切速度和不连续地形的垂直(2D)层析图像。这些层析图像显示了与地形和大地水准面很好相关的特征，但不是以目前海洋地幔动力学模型所预期的方式；因此，这些结果对地幔动力学具有潜在的深远影响。这里提出的研究的首要任务将是收集中太平洋和西太平洋的综合数据集，并为该区域的高分辨率三维模型反演这些数据。这些数据将包括S体波和反射、上地幔导波、面波和ScS混响的旅行时和频散特征。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)通过扩展反演技术以包括幅度变化，这将允许调查衰减的横向变化，以及3)通过检查方位各向异性及其横向非均质性的影响。

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.