High Resolution Imaging of Seismic Velocity Discontinuities

提案EAR 0106904（PH #45 x）摘要标题：地震速度不连续性的高分辨率成像PI：Anne F. Sheehan，科罗拉多大学，博尔德地壳和地幔不连续性的存在和深度分布的地震估计是重要的约束模型的组成，流变学和温度在地球上。该项目包括开发、测试和应用接收器功能成像的新方法。一个基尔霍夫式偏移方法，利用点散射的方法来处理非平面和横向不连续的接口已经开发出来。这种分析中的一个不确定性是三维不连续结构的偏置效应，它可能会错误地将特征投影到二维模型中。偏移反演将扩展到三维，并包括背散射能量。正确评价这些P/SV偏移方法的精度和分辨率将需要开发一种合成地震记录方法，该方法可以处理3-D不连续地形和速度不均匀性，并将包括所有转换的相位和表面反射。将实施一种混合方法，该方法将使用射线理论将P波阵面传播到有限差分网格，该有限差分网格将跨越不连续性和表面之间的区域。这些技术将应用于西南太平洋和加州东部的区域数据集。这些努力对于今天的适当数据集非常有用，并且对于拟议的USAray和类似项目产生的数据集将变得越来越重要。

Abstract for proposal EAR0106904 (PH # 45x)Title: High Resolution Imaging of Seismic Velocity DiscontinuitiesPI: Anne F. Sheehan, University of Colorado, BoulderSeismic estimates of existence and depth distribution of crust and mantle discontinuities are important for constraining models of composition, rheology, and temperature in the Earth. This project includes development, testing, and application of new methods for receiver function imaging. A Kirchhoff-style migration methodology which utilizes a point-scattering approach to handle nonplanar and laterally discontinuous interfaces has been developed. An uncertainty in this analysis is the biasing effects of three-dimensional discontinuity structure that could falsely project features into two-dimensional models. The migration inversion will be extended to three dimensions, and include back-scattered energy. Proper evaluation of the accuracy and resolution of these P/SV migration methods will require development of a synthetic seismogram method that can handle 3-D discontinuity topography and velocity heterogeneity and which will include all converted phases and surface reflections. A hybrid method will be implemented that will use ray theory to propagate a P wavefront to a finite difference grid that will span the region between the discontinuities and the surface. These techniques will be applied to regional data sets from the southwest Pacific and eastern California. These efforts are of great utility with appropriate data sets today and will become increasingly important with data sets that will be generated by the proposed USArray and similar projects.