Spatial distribution of radon concentrations in Balakot-Bagh (B–B) Fault Line and adjoining areas, Lesser Himalayas, North Pakistan

Abstract

A study involving soil radon monitoring using RAD-7 instrument was carried out near Balakot-Bagh (B-B) Fault line hit by a 7.6 magnitude earthquake in October 2005. The study aimed to determine the spatial distribution of soil radon gas levels and the relationship between the soil radon gas and fracture density. Eleven soil samples were collected near the fault line, and 56 more samples (fourteen each from the adjoining district/area). Field measurements were made in the summer season of 2013, as a part of continuous measurement for regular monitoring the area for radon emanation and for observing the anomalies with previous values. The study area is located in Lesser Himalayas, North Pakistan, the Balakot–Bagh (B–B) fault in the Hazara–Kashmir Syntaxis. Soil gas radon concentrations were found higher near the Balakot-Bagh Fault line with an average value of 11.9 $${\text{kBq}}\;{{\text{m}}^{ - 3}}$$ compared to other sites of the study area with an average value of around 6.5 $${\text{kBq}}\;{{\text{m}}^{ - 3}}$$ . The radon value near the fault line is 70% higher as compared to the surrounding area.