近地表速度的约束层析反演

本文采用程函议程有限差分法计算通过速度模型的初至旅行时射线路径，然后引入先验地质信息和正则约束条件，用约束最小二乘交分解法（CLSQR）进行走时反演，获得近地表速度结构，这种层析反演方法以块体为基本单元，可以模拟和反演复杂速度结构，它不必识别波形，计算速度快，实际数据的反演结果表明，在复杂地表条件区表层速度存在强烈的横向变化，经层析反演获得的叠加剖面成像更加清晰。

Constrained tomographic inversion for near-surface velocity

The near-surface velocity structure can be obtained by first calculating ray path of first break travel-time passing through a velocity model by using finite-difference method for Eikonal equation and then by conducting travel-time inversion using introducing a priori geologic information and orthogonal constrained least square decomposition. The tomographic approach which basic unit is rectangular block can model and inverse the complex velocity structure. It doesn't have to identify waveform and can calculate quickly. Inversion results for real data show that there is strong lateral varation in near-surface velocity when the near-surface condition is complex and that resulted image on stack section is more clear after tomographic inversion.