Comment On "Origin Of Temporal Changes Of Inner-Core Seismic Waves" By Yang And Song (2020)

In this reply, we address the main issues raised by Yao et al. (2020) and conduct additional analyses, particularly on the seismic station clock problems and the influence of earthquake depth. We show that although the depth is an important issue to consider, the depth difference of our doublets is too small to be significant. Extensive analyses reaffirm our previous conclusions that (1) the inner core (IC) temporal changes come mostly from the interior (rather than its surface) and the proposal that the IC surface as the sole source of the temporal changes can be ruled out; (2) the most reasonable and simplest explanation so far for the temporal changes is an IC differential rotation; and (3) absolute-time based method in previous studies should be avoided for studies of temporal changes of less than 0.15 s unless the clock issue is resolved.