Abstract:In accordance with the practical issue that the imaging below the shielding high-velocity basalt in Lingbei area of Jiangling sag is difficult, the paper first analyzed the characters of basalt and influence on the rule of wavefield propagation and designed two corresponding theoretical models; using wave-equation wavefield numeric simulation technique and analyzing the characters of deep reflection seismic signal showed the low-frequency signals are characterized by having the strong capacity both penetrating thin shielding high-velocity basalt and reducing diffraction noises produced from rough surface. Application of the idea to practical data processing showed that using low-frequency signals can greatly reduce the influence of shielding high-velocity basalt, improving the imaging quality of deep beds below the shielding layer.