【摘要】 根据地震波传播的有限频理论,对于某个特定震相的观测信息,不仅射线路径上的点对该信息具有影响,射线领域上的其他点对接收信息也具有影响,这种影响可以用核函数来表达.本文基于波动方程的Born近似与Rytov近似,给出了非均匀介质情况下初至地震波振幅与走时菲涅尔体层析成像单频、带限层析核函数的计算方法.通过对均匀介质情况下初至地震波菲涅尔体层析成像核函数解析表达式的理论模型实验与分析,给出了不同维度振幅、走时单频菲涅尔体的空间分布范围,进而给出了带限菲涅尔体边界的确定方法.将本文的走时非涅尔体层析成像理论应用于表层速度结构反演中,理论模型试验与实际资料处理结果表明,初至波菲涅尔体地震层析成像方法比传统的初至波射线层析成像理沦具有更高的反演精度.更多还原

【Abstract】 According to the finite-frequency theory, for a single source-receiver pair, not only the points on the raypath but also those outside the ray affect the wave propagation. This kind of effect can be described by sensitivity kernel. On the basis of the Born and Rytov approximations, we derive the amplitude and traveltime sensitivity kernels for Fresnel volume tomography corresponding to different dimensions in heterogeneous medium. The analytical expressions of the sensitivity kernels in homogeneous media are presented, through which we give the distribution ranges of the amplitude and traveltime sensivitity kernels under different dimensions. Furthermore, we present the calculation methods of band-limited sensitivity kernels and the corresponding distribution ranges. According to the first arrival information of the seismic wave, we apply Fresnel volume tomography to the inversion of the near surface velocity of the earth. The inversion results of the theoretical model and practical data indicate that first arrival Fresnel volume tomography has the advantage of higher accuracy than the conventional raypath tomography.更多还原