Abstract: Jiayu fault has been confirmed as a concealed fault, which is located in the northeast of Jiayu county. The fault is about 40 kilometers long. It stretches nearly EW-NEE, traverses the Yangtze River from the southwest of Honghu Laowan, passing the northern edge of Maan Mountain, and extends eastward to the Futou Lake. Although the eastern end of the fault is clearly exposed, the tail of the fault is not apparent. The lack of small scale geophysical data in the area leads to the lack of relevant evidence for the trend and activity of the fault. In this study, shallow seismic wave combined with refraction tomography was used to receive artificial seismic wave at 2 meters interval. Through the use of multiple coverage technique and dense spot collection refraction records, the data were separately reflected and tomographically imaged, and then the shallow seismic reflection profiles and high-resolution refractive tomography profiles were obtained, and the data is interpreted by referring to the relevant regional seismic safety evaluation drilling data.. The comprehensive research results show that the application of shallow seismic reflection and high resolution refraction can be complementary, especially in the area where the external interference is serious, as the high-resolution seismic refraction tomography can reduce the chances of misjudgment of shallow seismic reflection. In addition, the study confirmed the specific location and its normal fault characteristics of Jiayu fault, which is characterized by the decline of the northern plate and the rise of the south plate, and the fault cut through the Quaternary sedimentary layer.

Key words: Jiayu fault, Quaternary activity, seismic reflection, high resolution refraction, tomography