基于相速度预测的FMM弹性TTI介质qP波射线追踪  

qP wave ray tracing in FMM elastic TTI media based on phase velocity prediction

作　　者：张志禹[1] 董雪 赵亦群 Zhang Zhiyu;Dong Xue;Zhao Yiqun(School of Electrical Engineering,Xi’an University of Technology,Xi’an 710048,China;School of Automation and Information Engineering,Xi’an University of Technology,Xi’an 710048,China)

机构地区：[1]西安理工大学电气工程学院,西安710048 [2]西安理工大学自动化与信息工程学院,西安710048

出　　处：《地震学报》2025年第2期153-168,共16页Acta Seismologica Sinica

基　　金：国家自然科学基金联合基金(U21A20485)资助。

摘　　要：快速准确地计算走时和射线路径是实现地震成像和反演的关键。在各向异性介质中,地震波的传播速度会随传播方向的变化而变化,这使得求解各向异性条件程函方程时,相速度的精确估计和计算变得非常复杂和困难,进而影响各向异性介质中走时和射线路径的计算精度和效率。为此,提出了一种基于相速度预测的射线追踪方法,该方法根据波的传播规律以及斯奈尔方程,推导出一种相速度预测公式,解决了各向异性条件程函方程中相速度求解困难的问题,实现了快速稳定的射线追踪。数值算例表明,本文所提出的改进算法明显提高了走时计算精度,耗时也仅比各向同性快速推进增加了14%,在复杂模型的应用中也表现出较强的适应性和稳定性。Fast and accurate calculation of travel time and ray path of seismic waves are two key problems in the field of seismic imaging and inversion.Solving these two problems plays a key role in the in-depth study of the fine structure of the Earth’s interior,the efficient exploration of the distribution of different types of resources underground,and even the scientific prediction of possible natural disasters.However,the situation becomes more complex when anisotropic media are involved.In such media,the velocity of seismic waves does not remain constant as in isotropic media,but varies with the propagation direction of seismic waves.This characteristic makes it a challenging task to calculate the propagation time of seismic waves and to determine the ray paths in anisotropic media.The conventional isotropic fast marching method(FMM)shows excellent performance advantages in solving the travel time problem in isotropic media.It is able to produce results relatively quickly and accurately due to its efficient algorithm and stable computational process.However,when we try to apply the method to solve the Eikonal equation under anisotropic conditions,we are faced with a critical aspect:the need for an accurate estimation of the phase velocity.This is because in an anisotropic medium,the velocity,anisotropy parameter and stratigraphic dip are not constant,and their dynamic changes make the calculation of the propagation direction complicated.The complex calculation of the propagation direction further increases the difficulty of phase velocity estimation.As a key parameter describing the velocity of seismic waves in a given direction,the accuracy of the phase velocity estimation is like the first domino in the chain,which directly affects the subsequent propagation time and the final accuracy of the ray path calculation.Any small deviation in the phase velocity estimate can be amplified in the subsequent calculations,leading to a large deviation of the final results from the actual situation.In this paper,the fast march

关 键 词：各向异性 快速推进方法 射线追踪 相速度 

分 类 号：P315.31[天文地球—地震学]