“…The pre-earthquake ionospheric perturbation is one of the most important phenomena of earthquakes precursor studies (Liu et al, 2001;Pulinets et al, 2003;Liu et al, 2006;He et al, 2011;Le et al, 2011;Sarkar et al, 2011;Parrot, 2012;Li and Parrot, 2013;Pisa et al, 2013;Guo et al, 2015;Rozhnoi et al, 2015). The total electron content (TEC) changes of the ionosphere associated with earthquakes have been reported by many researchers worldwide (e.g., Liu et al, 2001;Liu et al, 2004;Saroso et al, 2008;Heki, 2011;Heki and Enomoto, 2015;Iwata and Umeno, 2016;Liu et al, 2018;Tariq et al, 2019;Shah et al, 2020;Zhang et al, 2020). For instance, some studies displayed TEC anomalies prior to devastating earthquakes including the Wenchuan earthquake (Lin et al, 2009;Zhang et al, 2019), the Tohoku earthquake (Heki, 2011;Yao et al, 2012;Hirooka et al, 2016;Iwata and Umeno, 2016), and so on.…”