连续速度模型反演静校正技术的改进

Improvement of static corrections technique using continuous velocity model for inversion.

我国西部存在巨厚黄土区、无稳定潜水面的沙漠区及巨厚砾石堆积的山前带,其表层速度具有连续性特点,采用常规表层调查控制点法和初至折射法难以控制表层速度和厚度分布规律。为此,本文在以往的“连续速度模型反演静校正技术”的基础上,通过在反演过程中充分、合理地利用表层调查资料,结合大炮初至的回折波和折射波信息,进行连续速度模型反演,可精确地求出表层结构参数,再通过积分的方式计算出最终的静校正量。实例分析表明,文中所述方法较好地解决了表层速度在垂向上连续变化的西部地区的静校正问题。

In the west of China,there are areas of giant-thick loess, deserts with unstable water table and giant-thick-gravel-piled piedmont ,which is characterized by continuous near-surface velocity that using common method of controlling points of near-surface survey and first breaks refraction method to control the distributed regularity of near-surface velocity and density is very difficult. For that reason,on the basis of former 'static corrections technique using continuous velocity model for inversion',the paper conducts inversion using continuous velocity model through fully and reasonably using near-surface survey data during the inversion and in combining with inflexion wave and refractions of first breaks on the shot records, which can accurately solve the structural parameters of near-surface and then compute final statics by integration. The analysis of real cases showed that the method described in the paper can better solve the static corrections in the west of China where the near-surface velocity continuously changed vertically.