Tomographic Inversion for Mantle Shear Structure

这项研究的目的是调查地幔的横向不均一性，是三年前开始的工作的继续。结合以前的研究结果，这项研究将在北美和南美洲、东太平洋、北大西洋、北非和亚洲大陆下方约500公里的长度尺度上绘制剪切速度不均匀的三维地图。方法是收集研究区内所有可用的具有震源和接收器的切向分量地震记录。这些记录将使用合成地震图进行建模，以确定与观测到的到达相对应的射线路径和旅行时间。层析成像技术然后产生三维剪切波图。这项工作在岩石圈对流和由此产生的应力的地幔模型中具有重要的应用。因此，这对国家防震减灾计划具有重要意义。

The objective of this research is to investigate lateral heterogeneity in the Earth's mantle and is a continuation of work begun three years ago. In combination with previous results, the research will produce a three-dimensional map of shear velocity heterogeneity over length scales of about 500 km beneath North and South America, the East Pacific, the North Atlantic, North Africa and the Asian continent. The approach is to collect all available tangential component seismic recordings with sources and receivers in the study area. These records will be modeled using synthetic seismograms to determine the ray paths and travel times corresponding to observed arrivals. Tomographic techniques then produce the three-dimensional shear wave map. This work has important application to mantle models of convection and resulting stresses in the lithosphere. It is therefore important to the National Earthquake Hazard Reduction Program.