The Global Electric Circuit and Global Seismicity

Basing on the catalogue of earthquakes with a magnitude of M ≥ 4.5 for the period 1973–2017, a UT variation with an amplitude of ~10% in the number of earthquakes is revealed and compared with a UT variation in the ionospheric potential (IP) with an amplitude of ~18%. We demonstrate that the amplitude of the UT variation in the number of deep-focus earthquakes is greater compared with that of crustal earthquakes, reaching 19%. The UT of the primary maxima of both the IP (according to modern calculations) and of earthquake incidence coincides (near 17:00 UT) and is, by 2 h, ahead of the classical Carnegie curve representing the UT variation in the atmospheric electric field on the ground surface. The linear regression equation between these UT variations in the number of deep-focus earthquakes and the ionospheric potential is obtained, with a correlation coefficient of R = 0.97. The results support the idea that the processes of earthquake preparation are coupled to the functional processes of the global electric circuit and the generation of atmospheric electric fields. In particular, the observed increase in thunderstorm activity over earthquake preparation areas, provided by air ionization due to radon emanation, yields a clue as to why the global thunderstorm distribution is primarily continental. Another important conclusion is that, in observing the longitudinal distributions of earthquakes against the IP distribution, we automatically observe that all such events occur in local nighttime hours. Considering that the majority of earthquake precursors have their maximums at local night and demonstrating the positive deviation from the undisturbed value, we obtain a clue as to its positive correlation with variations in the ionospheric potential.

Radiometric analysis of micas used in many industries and evaluation of radiological hazards

Mica group minerals have been utilized in various industries such as paint, cement, rubber, plastic, paper, automotive, cosmetics, textile, etc. due to their unique electrical, thermal, and mechanical properties. In this study, the radiometric properties of 58 mica samples collected from three quarries operated commercially in Turkey were investigated using gamma-ray spectroscopy with an HPGe detector. The average activity concentrations of 226Ra, 232Th, and 40K analyzed in mica samples were found as 12, 44, and 2763 Bq kg−1, respectively. The radon emanation coefficient and radon mass exhalation rate of mica samples varied from 4 to 22% with an average of 10% and 0.4–5.9 µBq kg−1 s−1 with an average of 2.6 µBq kg−1 s−1, respectively. The radiological hazard caused by the utilization of mica samples as raw materials in the cement and concrete industry was evaluated for adults by calculating the gamma index and annual effective dose due to external exposure indoor. The study results revealed that there are no significant radiological hazards associated with the utilization of mica samples as building raw materials.

Radon emission fluctuation as a result of biochar application into the soil

The presented research was focused on the analysis of the impact of biochar application into the soil on the radon exhalation process as a new issue of radiation protection in agriculture. Field measurements of the radon exhalation rate utilizing two methods—active and passive as well as laboratory measurements of the radon emanation coefficient were performed. In laboratory a soil samples with sunflower husk biochar were analysed using the accumulation chamber technique. At the final step the assessment of the effective dose for humans coming from radon exhalation from soil depending on biochar dose applied were evaluated. The doses of biochar applied in the analysed experimental fields were 0, 20, 40, 60, 80, and 100 Mg ha−1. The results show that biochar application into the soil contribute to a decrease in the emanation coefficient from a value around 7% to less than 2% with a simultaneous decrease in the radon exhalation rate from 4.4 to 14.8 mBq m−2 s−1 when the biochar dose increase from 0 to 100 Mg ha−1.

Radon and magnetic anomalies in the territory of the city Kyiv: environmental aspect

Magnetic and radon anomalous fields are essential geophysical entities of environment which determine to a considerable degree its ecological state. Revelation of magnetic and radon anomalous zones is an urgent task for the studies of geo-environmental state of the territory and appraisal of its ecological safety. The greatest danger is produced by the areas where the faults are localized with radon anomalies related in the upper part of the Earth crust. For the territory of Kyiv geological characteristics of the studied area has been reviewd, schemes of regional and accompanying faults have been adjusted and completed, maps of module and anomalies of module of geomagnetic field induction as well as a scheme of radon anomalies in water and subsoil air have been elaborated. Connection between radon anomalies with faults and natural magnetic fields has been shown which consisted in correlation of radon anomalies with negative and small positive values of anomalous magnetic field and related to thick zones of fracturing with active fluidal-dynamic activity and the faults of diagonal and orthogonal systems being the zones of radon emanation into atmosphere. Radon anomalies in subsoil air are mainly controlled by Irpin-Borshchagivka, Pushcha-Vodytsya, Kyiv and Darnytsya faults of northwestern-northern strike and Petrivka-Pukhivka and Glevakha-Brovary faults of northwestern strike. For some stations of Kyiv metro the excess of environmental norms of magnetic field and radon anomalies has been determined which can be explained by constructive features of metro compartments and their location in fault zones. It has been shown that radon anomalies are spatially and temporally stabile and magnetic anomalies, especially in metro, are characterized by considerable changes of magnetic field in both low-frequency and high-frequency spectra of their variation. Combined analysis of the fault tectonic scheme, magnetic and radon anomalies will permit to find out environmentally hazardous zones in the territory of Kyiv and out of it more reasonably.

Preparation of multi-purpose radon emanation sources

The aim of this work was to prepare reference radon emanation sources traceable to primary standards to be used for radon-in-air as well as radon-in-water experiments. The feasibility of making stable radon emanation sources by drop deposition and chemisorption was studied. Experimental emanation coefficients for sources made by drop deposition and chemisorption ranged from 0.10 to 0.74 and from 0.18 to 0.25, respectively. These relatively low emanation coefficient values suggest that further method developments would be desirable. Proposals are made to improve chemisorption yield during source preparation and to obtain more accurate measurements on radon emanation coefficient.

An Experimental Apparatus for Monitoring Radon during Compression of Coal/Rock Samples and Its Preliminary Application

Based on the radionuclide distributions in sedimentary coal-bearing strata, this study analyzed the microrelease mechanisms of radon in coal-bearing strata. It was found that the microrelease process includes three stages: emanation, migration, and exhalation. Based on this, an experimental apparatus was independently designed for monitoring radon during compression of coal/rock samples from coal-bearing strata, whose major components include an electrohydraulic servocontrolled rock mechanics testing system, an airtight container, coal/rock samples, radon output device, and a continuous emanometer. The developed apparatus was preliminarily utilized for uniaxial compression tests on mudstone samples taken from the #21105 coalface of the Fourth Coal Mine in Yili Coalfield, China. The test results show that before sample failure under the uniaxial compressive load (UCL), the radon concentration is negatively correlated with the applied UCL and the magnitude of imposed elastic deformation. Increasing the applied load shortens the period of stable deformation, gradually decreasing the porosity of the rock, and as a result of declining the concentration of radon emanation from the rock. Finally, suggestions for future research are proposed, including mathematical equations to express the correlations between different experimental parameters and fractal characteristics of radon release from porous media.