A study of radon and thoron concentration in the soils along the active fault of NW Himalayas in India

The Study has been conducted to analyse the radon and thoron flux in the soil of Mandi district, Himachal Pradesh. The detectors have been rooted at seventy one lithological locations in the north-eastern part of the district. The average values of radon concentration has been observed as 4541 Bq/m(3) with maximum of 19970 Bq/m(3) at location no. 3 (N 32 degrees 00.46': E 76 degrees 51.74') and minimum of 867 Bq/m(3) at location no. 57 (N 31 degrees 45.65': E 76 degrees 51.56') and the thoron variation ranges from 37 to 6970Bq/m(3) with an average value of 1778 Bq/m(3). The radon liberation at different positions has been correlated to the presence of the active fault to reveal the contributory aspects for abnormal release of radon in the soils. The spatial distribution of radon and thoron gas along the lines passing through the fault zones have unveiled the variances connected to the local tectonic structures. Radon exhalation rates, radium contents and porosity of soil samples have been calculated and a correlation factor of 0.64 has been detected for the observed concentrations of thoron and the porosity of the soil.