TEMPORAL CHANGES IN THE INDOOR RADON CONCENTRATION AS AN EARTHQUAKE PRECURSOR
Keywords:Indoor radon concentration, Gyeongju, Seismic activities, Pohang, Radon anomaly
This paper reviews the changes in indoor radon concentrations, measured in a university building in Gyeongju, Rep. of Korea, to find the relationship, it exists, between the indoor radon concentrations and the seismic activities in the area neighboring Gyeongju. The measurement period was from June 1, 2017, to May 31, 2019. During this period, numerous seismic activities occurred in the southeastern region of the Korean peninsula. Considering the magnitude and distances from our measurement place to epicenters, 11 earthquakes for analysis were chosen. Among these, nine earthquakes were found to have radon anomalies before their occurrences. Three earthquakes with a magnitude greater than 4.0 were scrutinized for the correlation between radon anomalies. Effects of the environmental variables such as relative humidity, barometric pressure, rainfall, and inlet temperature were also examined. Similar to those found in our previous study, spike-like patterns were also found in the indoor radon concentration distributions before the earthquakes.