CEA Key Laboratory of Earthquake Prediction (Institute of Earthquake Forecasting), China Earthquake Administration, Beijing, 100036, China.
Hebei Earthquake Agency, Shijiazhuang, 050022, China.
Sci Rep. 2018 Nov 13;8(1):16772. doi: 10.1038/s41598-018-35262-1.
The release of radon in active fault zones is a sustained radioactive pollution source of the atmospheric environment. The species, concentration and flux of radon emitted in soil gas in active fault zones in the Capital of China were investigated by in-situ field measurements. Two main species of radon discharging from soil gas in active fault zones were identified, including radon diffused and dispersed from permeable soil, and upwelling from faults. Higher concentrations and flux of radon from faults were observed in the Bohai Bay Basin due to the accumulated uranium in the sandstone reservoirs and higher permeability of the strata and bed rocks. Increased radon released by strong earthquakes persists, with the max flux of 334.56 mBq m s observed in FN (Fengnan district) located at the epicenter of the 28 July, 1976 Tangshan M 7.8 earthquake. The level of radon released in 8 of 22 locations within the Basin and Range Province (to the west of Taihangshan piedmont fault Zone) reached level 2, and 13 of 14 locations within the Bohai Bay Basin reached levels 2-4, according to the Chinese Code (GB 50325-2001, 2006). Corresponding protective and safety measures should be in place to protect the health of nearby residents, due to their exposure to radon emitted from the faults. Also, the concentration of radon in active fault zones should be investigated to assess the possible risk, before land-use is planned.
活动断裂带中氡的释放是大气环境中持续的放射性污染源。通过现场原位测量，研究了中国首都活动断裂带土壤气体中氡的种类、浓度和通量。确定了从活动断裂带土壤气体中排放的两种主要氡种，包括从可渗透土壤扩散和分散的氡，以及从断层上升的氡。由于砂岩储层中铀的积累以及地层和基岩的渗透率较高，在渤海湾盆地观察到来自断层的氡浓度和通量更高。强烈地震释放的氡持续增加，在 1976 年 7 月 28 日唐山 M7.8 地震震中丰南（FN）地区，最大通量达到 334.56mBq·m·s。根据中国规范（GB50325-2001、2006），在盆地和山脉省（太行山山前断裂带以西）的 22 个地点中的 8 个地点和渤海湾盆地的 14 个地点中的 13 个地点，氡的释放水平达到 2 级，其中 14 个地点中的 13 个地点达到 2-4 级。由于附近居民暴露于来自断层的氡排放，因此应采取相应的保护和安全措施来保护他们的健康。此外，在规划土地用途之前，应调查活动断裂带中氡的浓度，以评估可能的风险。
