Seismological Investigations of Deep Earth Structure

EAR-9909267采集器来自全球地震台网的大量高质量数字记录的日益增多，使研究地球深部地震结构的各种新方法成为可能。通过分析数百或数千个地震图，通常有可能解决数据中的新特征，或者对以前在较小规模上解决的问题进行更全面的分析。该项目建议继续并扩大对全球地震数据集的分析，以解决地球深部结构的细节。建议的研究包括：1)利用PP和SS前兆分析上地幔不连续(410和660不连续)的幅度变化；2)利用反投影和偏移方法更好地成像地幔不连续结构(应用于SS前兆和接收函数)；3)模拟和反演PKP和PP前兆以绘制地幔小尺度不均匀的散射强度图；4)P波谱分析以解决地幔衰减的频率依赖性和横向变异性；5)系统地分析S转换相以识别与化学不均匀有关的中地幔不连续。

EAR-9909267ShearerThe increasing availability of large numbers of high-quality digitalrecords from the global seismic networks has made possible a variety of new ways to study deep Earth seismic structure. By analyzinghundreds or thousands of seismograms, it is often possible to resolvenew features in the data, or to perform more comprehensive analyses ofproblems that were previously addressed on smaller scales.This project proposes to continue and extend analyses of global seismic datasets to resolve details of deep Earth structure. Proposed studies include: 1) analysis of upper-mantle discontinuity (410- and 660-discontinuities) amplitude variations using PP and SS precursors, 2) the use of back-projection and migration methods to better image mantle discontinuity structure (applied to SS precursors and receiver functions), 3) modeling and inversion of PKP and PP precursors to map the intensity of scattering from small-scale heterogeneity in the mantle, 4) analyses of P-wave spectra to resolve the frequency dependence and lateral variability in mantle attenuation, and 5) systematic analysis of S-to-P converted phases to identify hypothesized discontinuities in the mid-mantle related to chemical heterogeneity.