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

Radon concentrations were measured in water of 4 wells on the Akşehir-Simav Fault System (ASFS) in Afyonkarahisar province from August 2009 to September 2010 and the relationship between radon anomalies and earthquake magnitudes was examined. Anomalous decreases in radon concentrations in the wells were observed to precede the earthquakes of magnitudes ranging from 2.6 M to 3.9 M. The correlation coefficients (R2) were 0.79, 0.93, 0.98 and 0.90 for the wells from 1 to 4, respectively, indicating that radon minima and earthquake magnitude were well correlated and suggesting that the groundwater radon, when observed at suitable sites, can be a sensitive tracer for strain changes in crust associated with earthquake occurrences. The relationship between the two parameters can be further improved as additional radon anomalies precursor to possible large earthquakes are recorded in the wells located on the ASFS in the future. This study strongly suggests that the continuous observations of radon concentrations in well water, especially at well 3, should be carried forward. ► Radon concentrations of 4 wells on the ASFS are reported for one-year period. ► Anomalous decreases were observed in radon concentrations in the wells. ► Radon minima are well correlated to the earthquake magnitude for each well. ► Groundwater radon minima may provide a forecasting for local disastrous earthquakes. ► The study suggests carrying on the continuous observations in this province.