“…Rn is produced by the radium series in uranium‐bearing materials. Emission of Rn through active fault zones can be enhanced by seismic, volcanic and fault activities, which is demonstrated by high concentrations and flux of soil Rn worldwide (Ambrosino, Sabbarese, Roca, Giudicepietro, & Chiodini, 2020; Ambrosino, Sabbarese, Roca, Giudicepietro, & De Cesare, 2020; İçhedef et al., 2014; Kamislioglu and Külahci, 2016; Oh & Kim, 2015; Sabbarese et al., 2020; T. F. Yang et al., 2004). Anomalous discharge of CO 2 ‐rich fluid was directly measured during the 1965–1967 Matsushiro earthquakes (Cappa et al., 2009).…”