Mapping Earth Structure

9316441海姆伯格这项研究是为了确定地幔D“层的横向变化的详细性质，D”层就是地核上方的部分。目前大多数成像这种深部结构的方法必须对介于其间的地幔结构进行校正。由于推导出的地幔结构一致性较差，大多数三维全球模型预测的核相、PKP分支和SKS的差异时间不一致。这项工作将使用不同的时间和波形信息来评估深部地幔结构自下而上的横向变化，而不是正常的自上而下的过程。然而，这需要对内核和外核进行大量研究，以建立它们的一致性，以便正确地绘制不同时间的变化。***

9316441 Helmberger This research is to determine the detailed nature of the lateral variation in the D" layer of the earth's mantle, the portion just above the earth's core. Most of the present methods that image this deep structure must correct for the intervening mantle structure. Since there is poor consistency in derived mantle structure, most 3-D global models predict discordant differential times for core-phases, branches of PKP and SKS. This work will use differential times and waveform information to assess lateral variation in the deep mantle structure from the bottom-up, as opposed to the normal procedure of top-down. However, this requires a great deal of study of the inner and outer core to establish their uniformity so that variation in differential times are mapped properly. ***