Study on high-frequency MT method in candidate rock geologic structure detection for high level radioactive waste disposal

This paper present the primary achievement of the project "Geophysical detection to geological structure of pre-selected area for Chinese high level radioactivity waste repository in Beishan area, Gansu province". The study area is Beishan area, Gansu province, NW China-the most potential site for Chinese underground research laboratory and high level radioactivity waste repository. Based the research intention, and according to the geology, terrain and physiognomy conditions, geophysical survey with EH-4 conductivity imaging system was conducted in Xinchang section in order to identify the location of fracture and the interface between the pre-selected granite and peripheral rock body. In view of the longitudinal and transverse electricity features on the section plane, we analyzed the fracture's location, dipping angle and the rock interface position. The results are quite consistent with the geological mapping and the drilling observations. Simultaneity, the results show favorable prospect in the application of high frequency MT method (EH-4) to the deep geologic structure research of high-level radioactivity waste disposal area.