Reply to “Comment on ‘An Evaluation of the Timing Accuracy of Global and Regional Seismic Stations and Networks’ by Yang et al. (2021)” by Xin Zhang and Lianxing Wen

Abstract

Abstract The finding of Yang et al. (2021; hereafter, YSR21) casts fundamental doubts on all the previous studies on the temporal changes of the inner core (IC) surface that are based on absolute arrival times, including Wen (2006; hereafter, WEN06) and its follow-up studies. The reports of small time shifts of the IC-reflected phase (PKiKP) likely misinterpreted station-related issues (clock errors and instrument changes) as evidence for rapid localized deformation at the IC surface. The comment by Zhang and Wen (2024; hereafter, ZW24) aims at defending the results and conclusions of WEN06 by questioning a tiny portion of the results (2 out of over 400 doublets and 3 out of over 400 problematic stations) in YSR21. In response, we acknowledge an accidental error in table S1 of YSR21, which is corrected in an erratum (Yang et al., 2023), although this does not affect the results or interpretations of YSR21. However, we strongly disagree with the criticisms in ZW24 due to many problems therein, especially the issue of irreproducibility due to its inconsistent procedures with YSR21. While the problems are related to the use of absolute arrivals in the previous studies by Wen’s group, key problems in this new comment are related to questionable data selection and inconsistent processing. We further caution the metadata updates, particularly when involving small temporal change signals. We focus on the main points in ZW24 and demonstrate that its arguments are problematic in many aspects and do not diminish the credibility of YSR21 or other related works by Yang and Song in support of the IC differential rotation.