Spatial mapping of radon: Implication for fault delineation

Abstract

The spatial distribution of radon in soil and ground water is investigated in the proximity of Khairi Murat (KM) fault, Northern Pakistan. The present work is aimed to delineate the concealed segment of KM fault by analyzing the spatial distribution of radon in soil and ground water. Soil radon concentration is measured for 90 sampling points along 15 transverse profiles in the proximity of KM fault zone. A consistent trend of soil radon level for exposed and concealed segment of KM fault manifests the existence of subsurface fault structure. The anomalous radon level (2.40–3.35 kBq/m3) corresponds to sampling points adjacent to fault zone. Conversely, insignificant radon level (1.57–2.35 kBq/m3) corresponds to the distant sampling points from fault zone. Such heterogeneity of soil-radon level along transverse profiles reveals an evident correlation with seismogenic feature. In addition to that, ground water radon level, along (29.41 ± 5.2 Bq/L) and across (12.33 ± 3.2 Bq/L) the KM fault show a congruence with soil radon observations. Inclusively, our results suggest that spatial distribution of soil radon can serve as a useful tool for identification of concealed seismogenic features.