Global Analyses of Body Wave Travel Times and Amplitudes: Whole-Mantle Tomography and Simulations of 3-D Wave Propagation

建议摘要EAR0106666(PH#53x)标题：体波传播时间和幅度的全球分析：全地幔层析成像和三维波传播模拟PI：Jeroen Tromp和Jeroen E.Rithema，加州理工地震层析成像模型对地球科学中各种学科的研究人员都有好处。它们提供了大洋和大陆岩石圈结构的图像，并在限制地幔对流的平面形态方面发挥了核心作用。为了改进这些模型，我们将构建新的层析模型，其中我们将利用过去几年收集的大量地震数据集。它包括独特的数据类型，如高模瑞雷波相速测量和转换体波相位的走时(如SP、SKP)，这些数据类型在层析成像中尚未得到充分利用。在平行的研究中，我们应用新的Komatitsch和Tromp[1999]的谱元素方法来研究三维地幔结构对长周期体波传播的影响。具体地说，我们将检验射线理论在低度地震模型中对波传播的适用性，地幔深部的小尺度结构，如地柱，是否产生特征的、可观察到的旅行时或波形变化，以及是否可以用地幔地震速度的大尺度变化来解释长周期体波幅度异常的大尺度模式。这些分析提供了对当今断层成像模型的质量的洞察，并帮助我们设计了当完全三维正演理论可以被结合时的下一代断层成像反转。

Abstract for proposal EAR0106666 (PH # 53x)Title: Global Analyses of Body Wave Travel Times and Amplitudes: Whole-mantle Tomography and Simulations of 3-D Wave PropagationPI's: Jeroen Tromp and Jeroen E. Ritsema, Cal TechSeismic tomographic models are beneficial to researchers from a wide variety of disciplines in the Earth Sciences. They provide images of the structure of oceanic and continental lithosphere, and play a central role in constraining the planform of convection in the mantle.To improve these models, we will construct new tomographic models in which we will take advantage of the extensive seismic data set that we have compiled in the past several years. It includes unique data types, such as higher-mode Rayleigh wave phase-velocity measurements and travel times of converted body-wave phases (e.g., SP, SKP), which have not been fully exploited in tomography.In a parallel research effort, we apply the new Spectral Element Method of Komatitsch and Tromp [1999] to study the effects of 3-D mantle structure on long-period body-wave propagation. Specifically, we will test the applicability of ray theory to wave propagation in `low-degree' seismic models, whether small-scale structure in the deep mantle, such as plumes, produce characteristic, observable travel-time or waveform variations, and whether the large-scale pattern of long-period body-wave amplitude anomalies can be explained by large-scale variation of seismic velocity in the mantle. These analyses provide insight into the quality of present-day tomographic models and help us design the next generation of tomographic inversions when fully 3-D forward theories can be incorporated.