Misinterpreted Seismic Evidence for Localized Rapid Changes of the Inner Core Boundary Surface.

The nature of the inner core (IC) temporal changes is of great importance in understanding the deep earth dynamics. The comment by Tian and Wen (2023, https://doi.org/10.1029/2023gl103173) on our previous paper (Yang & Song, 2022, https://doi.org/10.1029/2022gl098393) provided a new observation as evidence against the IC rotation and proposed that our observations are instead from localized rapid changes at the IC surface. Here we argue the opposite to its conclusions. The comment misinterpreted our logic and many of our observations and arguments. Its one new waveform does not contradict with the "rotation" model. The original evidence for the "surface" model is demonstrated to be an artifact from station clock errors and instrument changes. Additionally, the surface model lacks a solid physical and quantitative basis to explain existing seismic evidence. We conclude that the rotation model is currently the best interpretation and the surface model is not a viable alternative. Plain Language Summary: Seismic waves traversing the Earth's inner core (IC) from repeating earthquakes exhibit significant temporal changes in their arrival times. The intriguing observation has been generally considered as evidence of the IC rotation (relative to the mantle) shifting the IC's laterally varying structures, which is further supported by the compelling evidence in Yang and Song (2022, https://doi.org/10.1029/2022gl098393). In the comment by Tian and Wen (2023, https://doi.org/10.1029/2023gl103173) on our study, they made harsh criticisms of our research and argued against the IC rotation, and proposed instead that the seismic observations result from localized topographic changes at the IC surface. In response, we believe that they misunderstood our logic and misinterpreted a number of our observations and arguments. The only one new example they presented does not contradict with the IC rotation model. Moreover, the original evidence supporting the IC surface change (Wen, 2006, https://doi.org/10.1126/science.1131692) is actually an artifact caused by station clock errors and instrument changes. They neglected substantial evidence that contradicts their proposed model but supports the IC rotation. Their model also lacks a quantitative physical basis. In conclusion, their comment does not diminish our confidence in the rotation model in our original paper and their proposed alternative model is not viable. Key Points: The comment misinterpreted our logic and arguments and failed to consider a large body of disadvantageous evidence from previous studiesThe only one new waveform does not contradict with the inner core (IC) rotation, while all the data from 10 doublets are consistent with itThe model of IC surface change can be ruled out, which is based on misinterpreted evidence and lacks a physical and quantitative basis [ABSTRACT FROM AUTHOR]