Effect of Errors in the Migration Velocity Model of PS-Waves on Travel Time Accuracy in PSTM in Weak Anisotropic Media

P197 Effect of Errors in the Migration Velocity Model of PS-Waves on Travel Time Accuracy in PSTM in Weak Anisotropic Media H.C. Dai* (British Geological Survey) & X.Y. Li (British Geological Survey) SUMMARY We investigate the effect of errors in the migration velocity model of PS converted waves on the traveltime calculated in prestack time migration (PSTM) in weak anisotropic media. The PSTM operator contains four parameters PS-wave velocity vertical velocity ratio effect velocity ratio and anisotropic parameter. We derive four error factors corresponding to the four parameters respectively. Theoretical and numerical analyses of the error factors show that all