RESUMO
Earthquakes are one of the major causes of natural disasters and its forecasting is challenging task. Some precursory phenomenon exists in theory in relation to earthquakes occurrence. The emission of radioactive gas named 'radon' before the earthquakes is a potential earthquake precursory candidate. The study aims to monitor and to analyze the radon in relation to seismic activity in Northern Pakistan. For this purpose RTM-2200 has been used to monitor the changes in radon concentration from August 01, 2014 to January 31, 2015 in Northern Pakistan. Significant temporal variations has been observed in radon concentration. The bivariate analysis of radon with other variables manifests its positive relationship with air pressure and relative humidity and negative relationship with temperature. 2σ upper control limit on monthly basis are computed for detection of anomalous trends in the data. Overall increasing trend is detected in radon concentration. Five earthquakes from August 01, 2014 to January 31, 2015 have been selected from earthquake catalogue, depending upon their magnitude and distance from monitoring station and out of which radon concentration can be associated with only two earthquakes correlated with tectonic effect of radon concentration. Both of events have same magnitude 5.5 and occurred on September 13 and October 14, 2014 respectively. Very large variations have been observed in radon for the last two months of the study period, which may be occurred due to some other geological and environmental changes, but are not related to the earthquake activity.
