Investigation of Seismic Anisotropy above a Wadati-Benioff Zone

这项研究旨在分析南美洲西部两个地区上地幔的剪切波分裂，一个是哥伦比亚西部布卡拉曼加西南的火山区，另一个是秘鲁中部的一个大片非火山区。这项分析将涉及当地地震和远震地震的数据，并将用于与在布加拉曼加获得的结果进行比较，在那里，分裂被归因于紧邻瓦达蒂-贝尼奥夫带上方的上地幔中的楔形各向异性体积，特别是在火山环境和非火山环境中。这一结果将与俯冲板块引起的地幔变形模型有关，从而与世界上最活跃的地震区之一的地震孕育机制有关。这项研究是国家减少地震灾害计划的一部分。

This research is to analyze shear-wave splitting in the upper mantle in two areas in western South America, a volcanic area southwest of Bucaramanga in western Colombia, and a large non- volcanic area in central Peru. This analysis will involve data from both local and teleseismic earthquakes and will be used to compare to results obtained at Bucaramanga where splitting was ascribed to a wedge-shaped anisotropic volume in the upper mantle immediately above the Wadati-Benioff zone, especially in a volcanic versus a non-volcanic setting. The results will bear on models of deformation of the mantle due to the subducting slab and thereby on the mechanism of earthquake generation in one of the world's most active seismic areas. This research is a component of the National Earthquake Hazard Reduction Program.