“…The ionosphere layer can be disrupted by earthquakes, tsunamis, volcanic eruptions, and other natural disasters, and these anomalies have been observed using the GNSS TEC. During these events, acoustic waves propagate upward to the ionosphere layer and are monitored using the TEC (Cahyadi, 2014;Cahyadi et al, 2018Cahyadi et al, , 2022Cahyadi & Heki, 2013a, 2013bHeki & Cahyadi, 2012;Jin et al, 2015;Jin & Su, 2019;Liu et al, 2011;Sharma et al, 2017), tsunamis (Kakinami et al, 2012;Liu et al, 2006;Muslim et al, 2020;Rolland et al, 2010), geomagnetic storms (Jenan et al, 2022;Jin et al, 2017;Sori et al, 2021), and volcanic eruption (Cahyadi et al, 2020(Cahyadi et al, , 2021Nakashima et al, 2014Nakashima et al, , 2016Shults et al, 2016). This is due to the fact that these natural disasters are propagating acoustic waves upward to the ionosphere layer, which was monitored using the TEC (Cahyadi & Heki, 2015).…”