Bounds on Anisotropic Velocity Heterogeneity from Surface Waves and Body Phases

表面波和体相的各向异性速度不均匀性的界限

• 批准号: 8721144
• 负责人: Arthur Lerner-Lam
• 金额: --
• 依托单位: Columbia University Lamont Doherty Earth Observatory
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-02-01 至 1989-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8721144&HistoricalAwards=false
• 关键词: Bounds; Anisotropic; Velocity; Heterogeneity; Surface

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.

我们请求研究太平洋下方的横向外侧异质性和各向异性，该技术使用一种将直接用于地球结构的三成分基本和高模式的表面波和身体相波形式的技术进行研究。我们将最初的工作集中在西部，北部和西北太平洋盆地上，从而积累了GDSN和WWSSN网络的数据。我们对横穿该区域的波形的最初观察结果显示了上柱上各向异性和异质性的大量证据，不容易通过简单的年龄依赖性模型来解释，包括夏威夷西北部西北部旋转的大面积异常的快速速度和Shatsky Rise。对“正常”路径的极化各向异性的初步估计表明，SH速度到处的速度比低速区域底部的速度快于SV速度。合成数据的实验证明了我们技术能够以深度和盖子/各向异性权衡解决各向异性的分布。