Free Oscillations and Large-Scale Lateral Heterogeneity of the Earth

本研究旨在进一步发展利用长周期地震资料确定地球三维结构的理论基础。下一个重大进展将是反转一个数量级更大的数据集，其数量级约为5万个源-接收器对，这些数据将在其他地方开发。这里的注意力将集中在在如此大规模的研究中必须采用的各种近似和技术的准确性和可能的偏差。要解决的具体问题是合成长周期地震记录的准确计算，近似方法和反演技术的评估，以及几何光学、各向异性和Born近似的理论研究。

This research is to develop further the theoretical basis for determining 3-D earth structure from long-period seismic data. The next major advance will be to invert a dataset that is an order of magnitude larger, of the order of 50,000 source-receiver pairs which will be developed elsewhere. Attention here will be focused on the accuracy and possible biases of the various approximations and techniques that will have to be employed in such a large-scale study. Specific topics to be addressed are the accurate computation of synthetic long-period seismograms, evaluation of approximate methods and inversion techniques, and theoretical studies of geometrical optics, anisotropy, and the Born approximation.