1�� College of Geo-exploration Science and Technology��Jilin University��Changchun 130026��China; 2�� The Tenth Institute of Geology and Mineral Exploration and Development��Chifeng��Inner Mongolia 024005��China

When the conventional seismic data processing methods failed to acquire the satisfactory imaging results of subsurface steep structure��the virtual source method should be applied to convert the traditional vertical seismic profile ( VSP��vertical seismic prodile) gathers into virtual single well profile ( SWP��single well profile) gathers�� After that��geometry was reconstructed closer to the structure targets near wells to get the better image resolution of subsurface geological body��and the seismic source and geophone under complex overburden to avoid the effect by unknown velocity information between wells and surface�� Especially��when the steep structure such as faults present in the subsurface��the virtual source method can produce better image results�� The authors modeled acoustic and elastic data��set the faults as steep structures��and tested the ability of virtual source method to detect the steep structure in the subsurface��which obtained the satisfactory imaging results of acoustic and elastic medium�� This method still gets the good imaging results when sparse geometry was used to survey��