“…For example, Kondratenko and Nersesov (1962) is only valid for earthquakes with Mw ≤ 3.0 while Rikitake (1975) was not established by means of ionospheric observations, which are extremely dynamic in nature, but rather on the first and second states of solid and liquid (i.e. mechanical processes) (Chen et al 2011). It incorporates in-situ precursory phenomena such as resistivity, radon emissions and light effects (Su and Liu 2014).…”