Normal seasonal variations for atmospheric radon concentration: a sinusoidal model. (January 2015)

• Record Type: Journal Article
• Authors: Hayashi, Koseki; Yasuoka, Yumi; Nagahama, Hiroyuki; Muto, Jun; Ishikawa, Tetsuo; Omori, Yasutaka; Suzuki, Toshiyuki; Homma, Yoshimi; Mukai, Takahiro
• Is Part Of: Journal of environmental radioactivity. Volume 139(2015:Jan.)
• Page Start: 149
• Page End: 153
• Publication Date: 2015-01
• Subjects: Atmospheric radon -- Seasonal variation -- Sinusoidal model -- Atmospheric turbulence; Radioactivity -- Periodicals; Radiation, Background -- Periodicals; Radioecology -- Periodicals; Radioactive pollution -- Periodicals; Environmental Pollutants -- Periodicals; Radioactive Pollutants -- Periodicals; Radioactivity -- Periodicals; Radioécologie -- Périodiques; Pollution radioactive -- Périodiques; Fond de rayonnement -- Périodiques; 539.752
• DOI: 10.1016/j.jenvrad.2014.10.007
• Languages: English
• ISSNs: 0265-931X

Abstract

Abstract: Anomalous radon readings in air have been reported before an earthquake activity. However, careful measurements of atmospheric radon concentrations during a normal period are required to identify anomalous variations in a precursor period. In this study, we obtained radon concentration data for 5 years (2003–2007) that can be considered a normal period and compared it with data from the precursory period of 2008 until March 2011, when the 2011 Tohoku-Oki Earthquake occurred. Then, we established a model for seasonal variation by fitting a sinusoidal model to the radon concentration data during the normal period, considering that the seasonal variation was affected by atmospheric turbulence. By determining the amplitude in the sinusoidal model, the normal variation of the radon concentration can be estimated. Thus, the results of this method can be applied to identify anomalous radon variations before an earthquake. Graphical abstract: Highlights: Normal seasonal variation of the atmospheric radon concentration was determined by accurately fitting with a sinusoidal model. The seasonal variation in data was affected by atmospheric turbulence. The normal radon pattern was used to extract precursory changes before earthquakes.