Determination of the relationship between radon anomalies and earthquakes in well waters on the Akşehir-Simav Fault System in Afyonkarahisar province, Turkey

Multiple sclerosis prevalence and its relationship with economic status in Afyonkarahisar, Turkey

BACKGROUND

Over the past decade, the prevalence of Multiple Sclerosis (MS) has increased in Turkey. However, the prevalence of MS in Middle Anatolia, specifically Afyonkarahisar, remains unknown. Additionally, the potential link between economic status and MS has not yet been explored in Turkey.

METHODS

A stratified sampling method was employed to select samples from the population residing in Afyonkarahisar City Center, taking into account demographic factors such as income level, sex, and age. The sample size was calculated using the formula N = p.q.Zα2/d2, where an average prevalence rate of 70/100,000 was considered based on previous studies. The minimum sample size was 29,858. Considering incomplete, inaccurate, and low-reliability data, data were collected from 30,500 individuals and 30,408 individuals were evaluated.

RESULTS

The prevalence of Multiple Sclerosis in the center of Afyonkarahisar was 105.2 per 100,000 individuals. Upon investigating the association between economic status and MS prevalence, the findings revealed rates of 193.6 per 100,000 in individuals with high income, contrasting with 80.2 per 100,000 in those with low income. Notably, a heightened prevalence of MS is evident among individuals with higher income levels.

CONCLUSION

This study revealed a significantly elevated prevalence of MS in Afyonkarahisar, the highest in Turkey. The inverse correlation between the prevalence of MS and socioeconomic status is intriguing. Possible reasons for the high prevalence include the relatively new and specific geologic and environmental conditions in the area.

Radon concentration in spring water as an indicator of seismic activity: a case study of the Muzaffarabad Fault in Pakistan

Radon and its progenies found in water indicate the existence of seismically active faults in the region. However, exposure to high levels of radon can also result in radiation-related health risks. This study focuses on radon-based active tectonic studies along the Muzaffarabad Fault in the core of the Hazara-Kashmir Syntaxis (HKS), NW Himalayas, Pakistan. In this study, spring water samples were collected along roadside of Jhelum Valley and in close proximity to the Muzaffarabad Fault in Pakistan using Radon Thoron Monitor (RTM1688-2). The results of the study showed that the radon concentrations in the water samples ranged from 1.895 to 17.097 Bq/l. The study found that the highest radon concentration was observed in the samples collected closest to the fault, while the lowest concentration was observed in the samples collected further away. The statistical analysis between the radon concentration and the distance from the fault showed a strong inverse relationship (R2=0.73). The study also found that 68% of the sampling sites had radon concentrations that exceeded the maximum contamination level (MCL) set by the US Environmental Protection Agency (EPA). The higher radon concentrations in the springs water suggest the probability of earthquake, which in turn poses potential health risks for the local population. The findings suggest that the measurement of radon concentration in water can be used as a tool for identifying seismically active faults in the region.

Application of radon (222Rn) as an environmental tracer in hydrogeological and geological investigations: An overview

Radon (²²²Rn) is a colourless, odourless, inert, and radioactive noble gas (t_1/2 = 3.8 days) that emanates from rocks and soils as a result of the alpha decay of its parent, radium (²²⁶Ra) in the decay series of uranium-238, is the focus of this study. Radon is produced in the crystal lattice of the minerals and emanates out through alpha recoil. It dissolves in water, and is also found in soil and air. Its distribution in water is more pertinent for scientific investigations. It can be measured by various methods. Certain properties of radon enable it to serve as an ideal tracer, viz., short-half life, inertness, high abundance in groundwater than surface water, preferential partitioning, sensitivity to sudden changes in subsurface conditions, non-invasiveness etc. This paper reviews the state-of-the-art techniques on the measurement of dissolved radon in water and its potential applications as a tracer and precursor in several hydrogeological and geological applications like understanding the surface water - groundwater interactions, hydrograph separation of streams, estimation of Submarine Groundwater Discharge (SGD), study of hydrodynamics and water balance of lakes, earthquake predictions, locating geological structures (faults/lineaments), geochemical explorations, NAPL contamination studies etc. Among the various applications presented, radon based approach is found to be more reliable in water resources domain than seismic precursory studies. The interpretations based on radon study in the above applications will pave the way for the improved understanding of the hydrological processes, and thus, help the planners and water managers for the sustainable development and management of water resources.

ANALYSIS OF RADON TIME SERIES RECORDED IN SLOVAK AND CZECH CAVES FOR THE DETECTION OF ANOMALIES DUE TO SEISMIC PHENOMENA

Anomalies in the radon (222Rn) releases in underground environments are one of the phenomena that can be observed before earthquake occurrence. Continuous measurements of radon activity concentration, and of meteorological parameters that influence the gas emission, were performed in three Slovak and Czech caves during 1-y period (1 July 2016-30 June 2017). The radon activity concentration in caves shows seasonal variations, with maxima reached during summer months. The anomalies in the radon time series are identified using a combination of three mathematical methods: multiple linear regression, empirical mode decomposition and support vector regression. The radon anomaly periods were compared with earthquake occurrences in Europe. Coincidences between both phenomena were found, since all monitored caves reflect contemporaneous local tectonic changes. The results indicate that radon continuous monitoring could assist a better understanding of radon emissions, along active tectonic structures, during seismic events.

Testing of 222Rn application for recognizing tectonic events observed on water-tube tiltmeters in underground Geodynamic Laboratory of Space Research Centre at Książ (the Sudetes, SW Poland)

Research on relationships between variation in ²²²Rn activity concentration and tectonic events recorded using the instruments of the Geodynamic Laboratory of SRC PAS at Książ (the Sudetes, SW Poland) had been conducted since 2014. The performed analyses of variation have demonstrated the spatial character of changes in ²²²Rn activity concentration. Their time-course is comparable in all parts of the underground laboratory. This means that gas exchange between the lithosphere and the atmosphere occurs not only through fault zones but also through all surfaces of the underground workings: the floors, the sidewalls and the roofs. Further, some relationships between ²²²Rn activity concentration and tectonic activity of the orogen have been demonstrated with the use of Pearson's linear correlation coefficient. The comparison between temporal distribution (times series) of radon activity concentration and water-tube tiltmeters (WTs) demonstrated that radon data have regular oscillations which can be approximated using the sine function with a 12 month cycle (seasonal changes) and amplitude in the range of 1000-1500 Bq/m³. To compare the collected radon signal data and tectonic activity, we used linear function as the simplest method of trend assessment. Pearson's correlation coefficient r cannot be accepted as appropriate for assessing the interdependencies between variables because they do not have a normal distribution, and the relationship between them is not linear. It was noted that each series of data, namely radon activity concentration and tectonic activity determine the series of deviations above and below the trend function. Because of the non-fulfillment of the above assumptions, we used nonparametric equivalents such as Spearman's rank correlation coefficient r_s and Kendall's tau. The obtained results showed that the value of the r_s coefficient ranges from 0.38 to even 0.43. The best relationship at the level of r_s = 0.43 was determined between the radon activity concentration recorded by detector no. 3 and the tectonic activity of the rock mass registered on the WT-2 channel. Similar at the r_s level of 0.37-0.38 between detector no. 5 and 4 and the WT-2 channel. A bit higher than r_s = 0.39 between detector no. 3 and the WT-2 channel. In each case, these were positive correlations. The obtained Spearman's r_s coefficients indicate the correlation between ²²²Rn activity concentration and tectonic activity of the rock mass. The t-statistic, which analyzes the significance of Spearman's coefficient r_s is a descriptive measure of the accuracy of regression matching to empirical data. It takes values in the range of percentage and provides informations about which part of the total variability of the radon activity concentration (Y) observed in the sample has been explained (determined) by regression in relation to tectonic activity of the rock mass (X). In our case, approximately f 40% to more than 50% of the radon activity concentration (Y) was explained by regression in relation to the tectonic activity of the rock mass. We obtained similar results with the use of Kendall's tau coefficient. Precise description of the character of this relationship requires further, more detailed analyses, such as comparing characteristics of the distributions based on trend variation like Monte Carlo simulation, Multivariate Adaptive Regression Splines or neural networks.

Mathematical and geophysical methods for searching anomalies of the Radon signal related to earthquakes

A detailed analysis of a time-series of the Radon (222Rn) specific activity is carried out to identify anomalies that can be correlated with earthquakes occurrence in the monitored area. New hybrid methods are developed for this purpose and the advantages of each single component method are exploited. These methods are applied to two-years data series recorded continuously in the soils of a site within the seismo-volcanic area of Phlegrean Fields (Naples-Italy). Since the measurement system distinguishes and separately measures the 222Rn and 220Rn, an alternative estimation of the remote fraction of the gas and its anomalies has been also performed using the 220Rn trend. The results of different methods are compared to recognize and to highlight Radon anomalies. Clear relationships have been found between anomalies and earthquakes of local origin and selected according to a specific formula of the earthquake preparation zone. The effectiveness of the methods and the goodness of the results are established by the high values of the cross correlation factors between the anomalies and the occurrence of the earthquakes.

Results of the simultaneous measurements of radon around the Black Sea for seismological applications

Results of measurements of radon around of the Black Sea are shown. Radon stations in zones of active faults were placed. Simultaneous hourly measurements of soil radon in 2005 were carried out in the Sivrice Fault Zone that is a segment of East Anatolian Fault System, in the town of Tbilisi (Georgia) and in the South Russia. In 2008 simultaneously hourly measurements of soil radon were carried out in the Western Caucasus (Russia) and in the Mytilene Island (Greece). In 2013 radon in underground waters simultaneously in midday was measuring in Crete (Greece), in the Pamukkale geothermal region (Southwest Turkey) and in the Western Caucasus. Measurements of radon concentration in the points located around of the Black Sea have shown identical regularities in changes of the data. Influence of meteorological, tidal and solar factors on changes of water radon concentrations and soil radon concentrations was observed in all researches points. But this influence was insignificant. Seismological application of observed results also was considered. Various mathematical methods of definition of anomaly in the radon data during earthquakes were considered. During researches in the Black Sea region basically earthquakes with M from 2.0 up to 5.0 and in a depth about 10 km were occurred. For these earthquakes method of daily subtraction of the data of the next and previous day was used. This method has allowed solving a problem with a choice of average value. Probability up to 0.69 (number of earthquakes with radon anomalies/total number of earthquakes) of detection of radon anomalies before earthquakes was achieved applying this method. Changes of radon maps before regional earthquakes were also observed. The frequency analysis of variations of the radon data on the basis of the Wavelet analysis was carried out. Occurrence of the short periods (about 2 days) was observed during regional earthquakes.

Measurement of radon in ground waters of the Western Caucasus for seismological application

Results of radon ((222)Rn) concentration measurement in ground waters in the Western Caucasus are described. In 2010-2011 each day at 12:00 Moscow winter time (9:00 GMT) sampling in volume of 0.5 l of waters was carried out in two wells at depth of 30 m and 180 m. In 2012 three times per day (7:00, 12:00, 17:00) this sampling was already carried out. Radon from water was extracting by degassing method with use of bubbler. Measurements of alpha activity of gas in scintillation (ZnS) chambers were done. The water radon data with seismic, meteorological and the Sun-Lunar data were compared. The mathematical method of definition of "splashes" in radon data before regional earthquakes is considered. The greatest probability in 72% of the forecast of regional earthquakes for the data from a well of 30 m depth was received. Correlation between meteo and radon data is absent. Correlation of lunar phases and solar activity with radon data is discussed. In July-December, 2012 sampling of water from 15 wells and measurements of radon were carried out. The distance between wells was near 50 km. Changes of radon maps in territory of South Russia during earthquakes are shown.

Application of spectral decomposition of ²²²Rn activity concentration signal series measured in Niedźwiedzia Cave to identification of mechanisms responsible for different time-period variations

The authors present an application of spectral decomposition of (222)Rn activity concentration signal series as a mathematical tool used for distinguishing processes determining temporal changes of radon concentration in cave air. The authors demonstrate that decomposition of monitored signal such as (222)Rn activity concentration in cave air facilitates characterizing the processes affecting changes in the measured concentration of this gas. Thanks to this, one can better correlate and characterize the influence of various processes on radon behaviour in cave air. Distinguishing and characterising these processes enables the understanding of radon behaviour in cave environment and it may also enable and facilitate using radon as a precursor of geodynamic phenomena in the lithosphere. Thanks to the conducted analyses, the authors confirmed the unquestionable influence of convective air exchange between the cave and the atmosphere on seasonal and short-term (diurnal) changes in (222)Rn activity concentration in cave air. Thanks to the applied methodology of signal analysis and decomposition, the authors also identified a third process affecting (222)Rn activity concentration changes in cave air. This is a deterministic process causing changes in radon concentration, with a distribution different from the Gaussian one. The authors consider these changes to be the effect of turbulent air movements caused by the movement of visitors in caves. This movement is heterogeneous in terms of the number of visitors per group and the number of groups visiting a cave per day and per year. Such a process perfectly elucidates the observed character of the registered changes in (222)Rn activity concentration in one of the decomposed components of the analysed signal. The obtained results encourage further research into precise relationships between the registered (222)Rn activity concentration changes and factors causing them, as well as into using radon as a precursor of geodynamic phenomena in the lithosphere.

Measurements of radon concentrations in spa waters in Amasya, Turkey

Radon concentration measurements were performed in four spas used for therapy, drinking and irrigation purposes in the Amasya basin in Turkey, during a period of time between January 2009 and May 2010. The measurements were done using commercially available WG-1001 Vacuum Water Degassing System and the AB-5R Radiation Monitor manufactured by Pylon Electronics. The observed radon concentration values ranged from 0.11 to 0.71 Bq L⁻¹. Effective doses from inhalation of radon released from spa waters have been estimated between 0.28 and 1.78 μSv y⁻¹ .