Results

The sliding-window fk-analysis has been applied to all selected events in the dataset. For all time windows which fulfil the three precursor criteria (backazimuth, slowness and coherency) discussed in section 5.2 the differential travel times between PP and P$^d$P were determined. Then, the differential travel times were transformed to reflector depths using the one-dimensional Earth model IASP91 (Kennett and Engdahl, 1991). In chapter 5, the structure of the upper mantle in the Pacific was studied relative to PREM. The travel time difference of the PP - P differential travel time calculated for IASP91 and PREM is only 0.07s and is negligible for this study.
The reflections found are summarized in three groups according to their depths. The shallow discontinuities enclose reflections from 20 - 150 km. Then reflector depths of 150 - 250 km are discussed to study the depth range of the Lehmann discontinuity, and finally the depth range from 330 - 430 km as the depth of the 410-km discontinuity is shown.
Concluding, the results for the S$^d$S phases and the anisotropy study are discussed.