Abstract:In order to investigate geometry shape and activity of Luhuatai Fault Zone which locates in the northwest Yinchuan Basin,a 3D seismic exploration was completed whin an area of 550 m×875 m.The results show that it is a buried active fault zone and consisted of two faults,main fault F1 and secondary fault F2.The fault zone moved untill the late stage of Middle Pleistocene. Trend of F1 is SE,and F2 is NW,both of them are normal faults. The activity time of F1 is newer than that of F2,and the fault throw of F1 is larger than that of F2. The buried deepth of the upbreakpoint of F1 has a trend of increasing from North to South. The distance between F1 and F2 increases gradually from North to South on the horisontal plane,reduces gradually with depth increase on the vertical profile,and F2 merges into F1 at the depth of about
780-800 m.