Capability of TEC ’s CoRrelation Analysis (CRA) (Iwata and Umeno, 2016) for detecting preseismic anomaly is explained from the view point of the increase in signal-to-noise ratio to {\it amplify} preseismic TEC’s small anomaly signals with multiple sensor data synchronization and correlation to respond to all the criticisms proposed recently by Ikuta et al. 2021. Furthermore, deceleration at propagation velocities of MSTID before the 2016 Kumamoto earthquake firstly observed by CRA as velocity reduction of MSTID propagation in the F Layer of the ionosphere is then elucidated as a candidate of preseismic anomalies. This paper presents three models to explain its physical relationship with preseismic anomalies before large earthquakes. In particular, Model 1 predicts that the 35 m/s change in MSTID propagation velocities estimated by TEC’s CRA requires 0.58*10^{-3} V/m electric field change in the F Layer ionosphere, which is almost consistent with the estimation (Kelley et. al. 2017) in that the E*B/B^2 rift of 12 m/s for dislocations of electrons requires 0.5*10^{-3} V/m electric field in the E Layer to explain Heki’s finding of TEC anomaly behavior before the Tohoku-Oki earthquake. The \(10000\) times amplified effect of weak signals such as 0.58 mV/m in electrical field to affect MSTID propagation velocity change as is firstly observed by Iwata and Umeno, 2017 by CRA which has significant amplified capability. Contrary to the claim by Ikuta et al. 2021, TEC’s correlation anomalies detected (Iwata and Umeno 2016 and 2017) already provided supporting evidences that physical preseismic anomalies really exist.

Capability of TEC ’s CoRrelation Analysis (CRA) (Iwata and Umeno, JGR-Space Physics, 2016) for detecting preseismic anomalies is explained from the view point of the increase in signal-to-noise ratio to amplify preseismic TEC’s small anomaly signals with multiple sensor data synchronization and correlation. Furthermore, deceleration at propagation velocities of MSTID before the 2016 Kumamoto earthquake firstly observed by CRA (Iwata and Umeno, JGR-Space Physics, 2017) as velocity reduction of MSTID propagation in the F Layer of the ionosphere is then elucidated as a candidate of preseismic anomalies. A new physical model (Umeno, Nakabayashi, Iwata, Kao, 2021,DOI: 10.4236/ojer.2021.104008 ) which is recently constructed from the first principle to explain such ionospheric anomaly (ΔV=αΔE, Linear response theory of deceleration ΔV in propagation velocities of MSTID before large earthquakes with electric field change ΔE) is also presented to characterize preseismic ionospheric TEC anomalies by associating deceleration, acceleration, moving to the inverse direction of macroscopic ionic velocities before various large earthquakes such as our existing findings on ionospheric TEC anomaly before 2016 Tainan earthquake (Goto, Uchida, Igarashi, Chen, Kao, Umeno, JGR-Space Physics, 2019). In particular, this physical model predicts that the 35 m/s change in MSTID propagation velocities estimated by TEC’s CRA for 2016 Kumamoto earthquake requires 0.58 mV/m electric field change in the F Layer ionosphere, which is almost consistent with the estimation (Kelley et. al. JGR-Space Physics, 2017) in that the E✖︎B/B^2 drift of 12 m/s for dislocations of electrons requires 0.5 mV/m electric field in the E Layer to explain Heki’s finding of TEC anomaly behavior before the Tohoku-Oki earthquake. The 10000 times amplification effect of weak signals such as 0.5-0.58 mV/m in electrical field to affect MSTID propagation velocity change as is firstly observed by Iwata and Umeno, 2017 by CRA which means a significant signal amplification capability in this multi-sensor TEC correlation analysis (CRA). To summarize, various interrelation between physical models to exhibit TEC anomalies and observed TEC anomalies as above will be presented to understand preseismic ionospheric anomaly before large earthquakes.