地震波旅行时非线性/线性联合插值法

Nonlinear/linear interpolation of seismic traveltime

地震波旅行时计算是射线追踪方法的核心问题,其精度直接影响着路径的精度和正演模拟的准确程度。为了提高地震波旅行时的计算精度,基于Asakawa的旅行时线性插值法(LTI)提出了一种改进的射线追踪法——非线性/线性联合插值法,即在震源的近场采用非线性插值计算旅行时,在远场仍用LTI算法。非线性/线性联合插值法提高了近场旅行时的计算精度,进而提高了全场(尤其是远场)旅行时的计算精度。数值模拟和模型试算的结果表明,本文提出的非线性/线性联合插值法较传统的LTI算法更为精确。

The computation of seismic traveltime is a core matter of ray-tracing method, and its accuracy affects the accuracy of the path and the accurate degree of the forward of seismic ray simulation. This paper develops an improved ray-tracing method called nonlinear/linear traveltime interpolation based on the linear traveltime interpolation (LTI) method given by Asakawa to increase seismic traveltime computation accuracy. In the field near the source point, the traveltime of the interpolation point is calculated using nonlinear traveltime interpolation, while LTI is used to calculate the traveltime far from the source. The method improves the traveltime computation accuracy in the field near the source point, and thus, increases the traveltime computation accuracy in the full field (especially in the far field). A comparison of numerical and experimental results shows that the present algorithm is more accurate than the conventional LTI method.