Abstract <p>This article presents the results of radon observations conducted from 2012 to 2024 in the territory of the Timan–Pechora and Russian plates. The studies included profile and area measurements of radon volumetric activity in soil air within and near fault zones, as well as studies of the diurnal variation of radon volumetric activity. Based on analysis of a large data set, it was concluded that high concentrations of radon volumetric activity are characteristic of areas where outcrops of Riphean basement rocks are confined to fault systems. The size and shape of the anomalies are directly related to the internal structure of the fault systems. Diurnal and seasonal variations in radon volumetric activity depend on the dynamics of meteorological conditions. Soil radon level in a single area can vary by a factor of two to three.</p>