• 责任者：Zhang Zhi (Guangxi Scientific Experiment Center of Mining Metallurgy and Environment ; Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration ; Guilin University of Technology ; Guilin 541004 ; China) ; Liu Youshan
• 刊名：Chinese Journal of Geophysics
• 出版年：2013
• 卷期：56(10)
• 关键词：叠前偏移 ; prestack migration
• 页码：p.3523-3533
• 图表：11 illus., 2 tables, 56 refs.
• 分类号：1600
• issnNo：ISSN0001-5733
• isbnNo：CN11-2074/P

     A stable excitation amplitude （SEA） imaging condition for the elastic wave equation is proposed. In the propagation of the source wavefield extrapolation along a positive time axis, the energy density for total grid points are computed at each time-step, and the traveltime as well as wavefield values corresponding to the maximum energy density are saved as the excitation criterion. While in the propagation of the receiver wavefield extrapolation along a negative time axis, the excitation criterion is applied to obtain the imaging profiles at each grid point that satisfies the image time at each time step. Then the receiver wavefield is normalized by the source wavefield to form the angle-dependent reflection coefficient profiles. Compared to the normalized correlation （NC） imaging condition, the SEA imaging condition can eliminate the need of the harddisk, which saves a large volume of hard disk space （especially for three dimensions） and avoid a lot of I/O tasks. Consequently, the computational efficiency is enhanced significantly due to the application of SEA imaging condition. Compared to the excitation traveltime （ET） imaging condition in elastic media, the polarity reverse of horizontal component at opposite sides of the source will be corrected automatically to enhance the imaging when it involves in the stacking of many shot profiles, which is beneficial from the normalized amplitude （i. e. the angle-dependent reflection coefficients）. Numerical tests validate the feasibility of the SEA imaging condition. When comparing the NC imaging condition with the SEA imaging condition in the numerical tests, the latter has a small computational amount than the former, and the latter can produce less low-frequency artifacts, and also has better imaging capability as well as higher spatial resolution than the former.