The aim of this paper is to examine the anomalous variations of the critical frequency ($f_oF2$), total electron content (TEC), and $f_oE_s$ parameters before earthquake occurred on 1 April 2014 near Iquique Chile ($M=8.2$) and event on 25 October 2013 in Japan ($M=7.1$). Using the bound method we analyzed the variations of $f_oF2$, TEC, $f_oE_s$ and $N_mF2$ parameters. The anomalous variations in $f_oF2$, TEC, $f_oE_s$ and $N_mF2$ parameters observed 1 day, 15 days, 4 days and 1 day prior to Chile event and anomalous variations in $f_oF2$, TEC and $f_oE_s$ observed 3 days, 3 days and 2 days prior to earthquake event of Japan.
$f_oF2$, TEC, $f_oE_s$, $N_mF2$, earthquake, ionospheric precursors, bound method
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