Bounds on Anisotropic Velocity Heterogeneity from Surface Waves and Body Phases

我们要求研究太平洋下上地幔的横向不均匀性和各向异性，使用一种技术，该技术将三分量基波和高次模面波和体相波形直接反演为地球结构。我们将集中我们的初步工作在西部，北方，和西北太平洋海盆，积累数据从GDSN和WWSSN网络。我们对穿越该地区的波形的初步观察表明，上地幔各向异性和异质性的大量证据不容易用简单的年龄相关模型来解释，包括夏威夷西北隆起和沙茨基隆起下方的大面积异常快速度。极化各向异性的“正常”路径的初步估计表明，SH速度到处都快于SV速度至少到低速区的底部。与合成数据的实验表明，我们的技术来解决各向异性的分布与深度和盖子/各向异性权衡的能力。

We request for studies of the lateral heterogeneity and anisotropy of the upper-mantle beneath the Pacific Ocean, using a technique which inverts three-component fundamental and higher-mode surface-wave and body-phase waveforms directly for earth structure. We will concentrate our initial work on the western, northern, and northwestern Pacific Ocean basin, accumulating data from the GDSN and WWSSN networks. Our initial observations of waveforms traversing this region show substantial evidence for upper-mantle anisotropy and heterogeneity not easily explained by simple age-dependent models, including a large area of anomalous fast velocities beneath the northwestern Hawaiian Swell and the Shatsky Rise. Preliminary estimates of polarization anisotropy for "normal" paths indicate that SH velocities are everywhere faster than SV velocities at least to the bottom of the low-velocity zone. Experiments with synthetic data demonstrate the ability of our technique to resolve the distribution of anisotropy with depth and the lid/anisotropy tradeoff.