Abstract
Air absorbed dose rate data taken at 17 sites have been analyzed in order to understand the characteristics of dose rate levels in basaltic terrains. The dose rate increased with increase of K2O content of rock with high correlation coefficient. The contents of uranium, thorium and potassium in source materials of basaltic magma could be evaluated by fitting a model of equilibrium batch melting to the observed result. A semi-empirical formula expressing the dose rate as a function of K2O content was derived based on the above model.
