Emission of soil gas radon concentration around main central thrust in Ukhimath (Rudraprayag) region of Garhwal Himalaya

In this paper, the result of systematic measurement of the soil gas radon concentrations is discussed and the background values are defined along and around the Main Central Thrust (MCT) in Ukhimath region of Garhwal Himalaya, India. The Ukhimath region is being subjected to intense neotectonic activities like earthquake and landslide. For the systematic study, the measurement has been done in grid pattern form along and across the MCT. The soil gas radon concentrations were measured using RAD7 with appropriate accessories and followed proper protocol proposed by the manufacturer. The soil gas concentration was measured at different depths 10, 30 and 50 cm with a wide range of different points from the MCT. At 10 cm depth, the soil gas radon concentration was found to vary from 125 to 800 Bq m^-3 with an average of 433 Bq m^-3; at 30 cm, it was found to vary from 203 to 32 500 Bq m^-3 with an average of 2387 Bq m^-3; and at 50 cm, it was found to vary from 1330 to 46 000 Bq m^-3 with an average of 15 357 Bq m^-3. The data analysis clearly reveals anomalous values along the fault. (authors)